Radiology Review Manual (Dahnert, Radiology Review Manual)
Authors: Dahnert, Wolfgang
Title: Radiology Review Manual, 6th Edition
Copyright 2007 Lippincott Williams & Wilkins
> Table of Contents > Musculoskeletal System
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Musculoskeletal System
Differential Diagnosis of Musculoskeletal Disorders
Differential-Diagnostic Gamut of Bone Disorders
Conditions to be considered = dissect bone disease with a DIATTOM
Dysplasia + Dystrophy
Infection
Anomalies of development
Tumor + tumorlike conditions
Trauma
Osteochondritis + ischemic necrosis
Metabolic disease
DYSPLASIA | = disturbance of bone growth |
DYSTROPHY | = disturbance of nutrition |
Limping child
1 4 Years
CONGENITAL
Developmental dysplasia of hip
TRAUMATIC
Toddler's fracture
Nonaccidental trauma
Other fractures
Foreign body
INFLAMMATORY
Diskitis
Septic arthritis
Osteomyelitis
Transient synovitis of hip
4 10 Years
TRAUMATIC
INFLAMMATORY
Septic arthritis
Osteomyelitis
Transient synovitis of hip
Diskitis
Juvenile rheumatoid arthritis
VASCULAR
Legg-Perthes disease
10 15 Years
TRAUMATIC
Stress fracture
Osteochondritis dissecans
Osgood-Schlatter disease
INFLAMMATORY
Juvenile rheumatoid arthritis
Ankylosing spondylitis
Septic arthritis
Osteomyelitis
HORMONAL
Epiphyseolysis of femoral head
Delayed bone age
CONSTITUTIONAL
Familial
IUGR
METABOLIC
Hypopituitarism
Hypothyroidism
Hypogonadism (Turner syndrome)
Cushing disease, steroid therapy
Diabetes mellitus
Rickets
Malnutrition
Irradiation of brain (for cerebral tumor / ALL)
SYSTEMIC DISEASE
Congenital heart disease
Renal disease
GI disease: celiac disease, Crohn disease, ulcerative colitis
Anemia
Bone marrow transplantation (<5 years of age)
SYNDROMES
Trisomies
Noonan disease
Cornelia de Lange syndrome
Cleidocranial dysplasia
Lesch-Nyhan disease
Metatrophic dwarfism
Bone sclerosis
Diffuse Osteosclerosis
mnemonic: | 5 M'S To PROoF |
Metastases
Myelofibrosis
Mastocytosis
Melorheostosis
Metabolic: hypervitaminosis D, fluorosis, hypothyroidism, phosphorus poisoning Sickle cell disease
Tuberous sclerosis
Pyknodysostosis, Paget disease
Renal osteodystrophy
Osteopetrosis
Fluorosis
Constitutional Sclerosing Bone Disease
Engelmann-Camurati disease
Infantile cortical hyperostosis
Melorheostosis
Osteopathia striata
Osteopetrosis
Osteopoikilosis
Pachydermoperiostosis
Pyknodysostosis
Van Buchem disease
Williams syndrome
P.2
Sclerosing Bone Dysplasia
Dysplasias of ENDOCHONDRAL OSSIFICATION (PRIMARY SPONGIOSA)
= failure in resorption + remodeling of primary immature spongiosa by osteoclasts
accumulation of calcified cartilage matrix packing the medullary cavit
Target sites: tubular + flat bones, vertebrae, skull base, ethmoids, ends of clavicle Osteopetrosis
Pyknodysostosis
Dysplasias of ENDOCHONDRAL OSSIFICATION (SECONDARY SPONGIOSA)
= errors in resorption + remodeling of secondary spongiosa
focal densities / striations
Enostosis
Osteopoikilosis
Osteopathia striata
Dysplasias of INTRAMEMBRANOUS OSSIFICATION
= disequilibrium between periosteal bone formation + endosteal bone resorption
Target sites: cortex of tubular + flat bones, calvaria, bones of upper face, tympanic parts of temporal bone, vomer, medial pterygoid
Progressive diaphyseal dysplasia
Hereditary multiple diaphyseal sclerosis (Ribbing disease)
Hyperostosis corticalis generalisata
Van Buchem disease
Sclerosteosis (Truswell-Hansen disease)
Worth disease
Nakamura disease
Diaphyseal dysplasia with anemia
Oculodento-osseous dysplasia
Trichodento-osseous dysplasia
Kenny-Caffey syndrome
MIXED SCLEROSING DYSPLASIAS
predominantly endochondral disturbance
Dysosteosclerosis
Metaphyseal dysplasia (Pyle disease)
Craniometaphyseal dysplasia
Frontometaphyseal dysplasia
predominantly intramembranous defects
Melorheostosis
Craniodiaphyseal dysplasia
Lenz-Majewski hyperostotic dwarfism
Progressive diaphyseal dysplasia
Solitary Osteosclerotic Lesion
DEVELOPMENTAL
Bone island
VASCULAR
Old bone infarct
Aseptic / ischemic / avascular necrosis
HEALING BONE LESION
trauma: callus formation in stress fracture
benign tumor: fibrous cortical defect / nonossifying fibroma, brown tumor; bone cyst
malignant tumor: lytic metastasis after radiation, chemo-, hormone therapy
INFECTION / INFLAMMATION
(low-grade chronic infection / healing infection)
Osteoid osteoma
Chronic / healed osteomyelitis: bacterial, tuberculous, fungal
Sclerosing osteomyelitis of Garr
Granuloma
Brodie abscess
BENIGN TUMOR
Osteoma
Osteoblastoma
Ossifying fibroma
Healed fibrous cortical defect
Enchondroma / osteochondroma
MALIGNANT TUMOR
Osteoblastic metastasis (prostate, breast)
Lymphoma
Sarcoma: osteo-, chondro-, Ewing sarcoma
OTHERS
Sclerotic phase of Paget disease
Fibrous dysplasia
Cortical Sclerotic Lesion in Child
Osteoid osteoma
Stress fracture
Chronic osteomyelitis
Healed fibrous cortical defect
Multiple Osteosclerotic Lesions
FAMILIAL
Osteopoikilosis
Enchondromatosis = Ollier disease
Melorheostosis
Multiple osteomas: associated with Gardner syndrome
Osteopetrosis
Pyknodysostosis
Osteopathia striata
Chondrodystrophia calcificans congenita= congenital stippled epiphyses
Multiple epiphyseal dysplasia = Fairbank disease
SYSTEMIC DISEASE
Mastocytosis = urticaria pigmentosa
Tuberous sclerosis
Bone-within-bone Appearance
= endosteal new bone formation
Normal
thoracic + lumbar vertebrae (in infants)
growth recovery lines (after infancy)
Infantile cortical hyperostosis (Caffey)
Sickle cell disease / thalassemia
Congenital syphilis
Osteopetrosis / oxalosis
Radiation
Acromegaly
Paget disease
Gaucher disease
P.3
mnemonic: | BLT PLT RSD RSD |
Bismuth ingestion
Lead ingestion
Thorium ingestion
Petrosis (osteopetrosis)
Leukemia
Tuberculosis
Rickets
Scurvy
Dtoxicity (vitamin D)
RSD (reflex sympathetic dystrophy)
Dense Metaphyseal Bands
mnemonic: | DENSE LINES |
D-vitamin intoxication
Elemental arsenic and heavy metals (lead, bismuth, phosphorus)
Normal variant
Systemic illness
Estrogen to mother during pregnancy
Leukemia
Infection (TORCH), Idiopathic hypercalcemia
Never forget healed rickets
Early hypothyroidism (cretinism)
Scurvy, congenital Syphilis, Sickle cell disease
also: methotrexate therapy
Osteopenia
= decrease in bone quantity maintaining normal quality
increased radiolucency of bone: vertical striations in vertebral bodies accentuation of tensile + compressive trabeculae of proximal femur reinforcement lines (= bone bars) crossing marrow cavity about knee cortical resorption of 2nd metacarpal: measuring outer cortical diameter (W) and width of medullary cavity (m) at midportion of bone and reporting combined cortical thickness (CCT)
subperiosteal tunneling
Categories:
DIFFUSE OSTEOPENIA
Osteoporosis = decreased osteoid production
Osteomalacia = undermineralization of osteoid
Hyperparathyroidism
Multiple myeloma / diffuse metastases
Drugs
Mastocytosis
Osteogenesis imperfecta
REGIONAL OSTEOPENIA
Osteoporosis
= reduced bone mass of normal composition secondary to
osteoclastic resorption (85%) (trabecular, endosteal, intracortical, subperiosteal)
osteocytic resorption (15%)
Incidence: | 7% of all women aged 35 40 years; 1 in 3 women > age 65 years |
Etiology:
CONGENITAL DISORDERS
Osteogenesis imperfecta
The only osteoporosis with bending!
Homocystinuria
IDIOPATHIC (bone loss begins earlier + proceeds more rapidly in women)
1. Juvenile osteoporosis: <20 years 2. Adult osteoporosis: 20 40 years 3. Postmenopausal osteoporosis: >50 years (40 50% lower trabecular bone mineral density in elderly than in young women) 4. Senile osteoporosis: >60 years progressively decreasing bone density at a rate of 8% in females; 3% in males NUTRITIONAL DISTURBANCES
scurvy; protein deficiency (malnutrition, nephrosis, chronic liver disease, alcoholism, anorexia nervosa, kwashiorkor, starvation), calcium deficiency
ENDOCRINOPATHY
Cushing disease, hypogonadism (Turner syndrome, eunuchoidism), hyperthyroidism, hyperparathyroidism, acromegaly, Addison disease, diabetes mellitus, pregnancy, paraneoplastic phenomenon in liver tumors
RENAL OSTEODYSTROPHY
decrease / same / increase in spinal trabecular bone; rapid loss in appendicular skeleton
IMMOBILIZATION = disuse osteoporosis
COLLAGEN DISEASE, RHEUMATOID ARTHRITIS
BONE MARROW REPLACEMENT
infiltration by lymphoma / leukemia (ALL), multiple myeloma, diffuse metastases, marrow hyperplasia secondary to hemolytic anemia
DRUG THERAPY
heparin (15,000 30,000 U for >6 months), methotrexate, corticosteroids, excessive alcohol consumption, smoking, Dilantin
RADIATION THERAPY
LOCALIZED OSTEOPOROSIS
Sudeck dystrophy, transient osteoporosis of hip, regional migratory osteoporosis of lower extremities
serum calcium, phosphorus, alkaline phosphatase frequently normal
hydroxyproline may be elevated during acute stage
Technique:
SINGLE-PHOTON ABSORPTIOMETRY
measures primarily cortical bone of appendicular bones, single-energy I-125 radioisotope source
Site: distal radius (= wrist bone density), os calcis Dose: 2 3 mrem Precision: 1 3%
DUAL-PHOTON ABSORPTIOMETRY
radioactive energy source with two photon peaks; should be reserved for patients <65 years of age because of interference from osteophytosis + vascular calcifications
Site: vertebrae, femoral neck Dose: 5 10 mrem Precision: 2 4%
SINGLE X-RAY ABSORPTIOMETRY
= area projectional technique for quantitative bone density measurement
P.4
Site: distal radius, calcaneus Dose: low Precision: 0.5 2%
DUAL ENERGY X-RAY ABSORPTIOMETRY (DEXA)
Most widely used & most precise technique! = quantitative digital radiography
= beams with two distinct energy levels allow identification of trabecular from cortical bone
has replaced dual-photon absorptiometry and is produced by x-ray tube with higher radiation flux than radioisotope source
Site: lumbar spine, femoral neck, whole body, forearm Dose: <3 mrem; Precision: 1 2% Data collected:
BMD (bone marrow density) value (g/cm2)
%BMD compared to young adults
%BMD compared to age-matched adults
T-score (SD of young-adult mean)
Z-score (SD of age-matched mean)
QUANTITATIVE COMPUTED TOMOGRAPHY
= determines true volumetric density (mg/cm3)
high-turnover cancellous bone is important for vertebral strength and has high responsiveness
trabecular bone + low-turnover compact bone can be measured separately
compared to external bone mineral reference phantom scanned simultaneously with patient to calibrate CT attenuation measurements 10-mm thick section with gantry angle correction through center of vertebral body Site: vertebrae L1 L3, other sites Use: assessment of vertebral fracture risk; measurement of age-related bone loss; follow-up of osteoporosis + metabolic bone disease (a) single energy: 300 500 mrem; 6 25% precision (b) dual energy: 750 800 mrem;5 10% precision Most sensitive technique!
PERIPHERAL QUANTITATIVE CT
= exact 3-dimensional localization of target volumes with multisection data acquisition capability covering a large volume of bone
Site: distal radius Location: axial skeleton (lower dorsal + lumbar spine), proximal humerus, neck of femur, wrist, ribs Radiographs are insensitive prior to bone loss of 25 30% Bone scans do NOT show a diffuse increase in activity DEXA Interpretation
Diagnosis T-score Management Follow-up Normal >1 prevention 3 years Osteopenia <-1 and >-2.5 prevention or therapy 2 years Osteopororis <-2.5 therapy 1 year decreased number + thickness of trabeculae cortical thinning (endosteal + intracortical resorption) juxtaarticular osteopenia with trabecular bone predominance delayed fracture healing with poor callus formation (DDx: abundant callus formation in osteogenesis imperfecta + Cushing syndrome)
Cx: (1) Fractures at sites rich in labile trabecular bone (eg, vertebrae, wrist) in postmenopausal osteoporosis (2) Fractures at sites containing cortical + trabecular bone (eg, hip) in senile osteoporosis
Rx: calcitonin, sodium fluoride, diphosphonates, parathyroid hormone supplements, estrogen replacement
Osteoporosis of Spine
diminished radiographic density vertical striations (= marked thinning of transverse trabeculae with relative accentuation of vertical trabeculae along lines of stress) accentuation of endplates picture framing (= accentuation of cortical outline with preservation of external dimensions secondary to endosteal + intracortical resorption) compression deformities with protrusion of intervertebral disks: biconcave vertebrae Schmorl nodes wedging decreased height of vertebrae
absence of osteophytes
Osteomalacia
= accumulation of excessive amounts of uncalcified osteoid with bone softening + insufficient mineralization of osteoid due to
high remodeling rate: excessive osteoid formation + normal / little mineralization
low remodeling rate: normal osteoid production + diminished mineralization
Etiology:
dietary deficiency of vitamin D3 + lack of solar irradiation
deficiency of metabolism of vitamin D:
chronic renal tubular disease
chronic administration of phenobarbital (alternate liver pathway)
diphenylhydantoin (interferes with vitamin D action on bowel)
decreased absorption of vitamin D:
malabsorption syndromes (most common)
partial gastrectomy (self-restriction of fatty foods)
decreased deposition of calcium in bone
diphosphonates (for treatment of Paget disease)
Histo: | excess of osteoid seams + decreased appositional rate |
bone pain / tenderness; muscular weakness
serum calcium slightly low / normal
decreased serum phosphorus
elevated serum alkaline phosphatase
P.5
uniform osteopenia fuzzy indistinct trabecular detail of endosteal surface coarsened frayed trabeculae decreased in number + size thin cortices of long bone bone deformity from softening: hourglass thorax bowing of long bones acetabular protrusion buckled / compressed pelvis biconcave vertebral bodies
increased incidence of insufficiency fractures pseudofractures = Looser zones mottled skull
Localized / Regional Osteopenia
Disuse osteoporosis / atrophy
Etiology: local immobilization secondary to fracture (more pronounced distal to fracture site)
neural paralysis
muscular paralysis
Reflex sympathetic dystrophy = Sudeck dystrophy
Regional migratory osteoporosis, transient regional osteoporosis of hip
Rheumatologic disorders
Infection: osteomyelitis, tuberculosis
Osteolytic tumor
Lytic phase of Paget disease
Early phase of bone infarct and hemorrhage
Burns + frostbite
Bone Marrow Edema
= hypointense on T1WI + hyperintense on T2WI relative to fatty marrow
Trauma
bone bruise
radiographically occult acute fracture
recent surgery
Infection = osteomyelitis
Aseptic arthritis
Osteonecrosis = early stage of AVN
Neuropathic osteoarthropathy
Reflex sympathetic dystrophy (some cases)
Transient osteoporosis of hip
Infiltrative neoplasm
Transverse Lucent Metaphyseal Lines
mnemonic: | LINING |
Leukemia
Illness, systemic (rickets, scurvy)
Normal variant
Infection, transplacental (congenital syphilis)
Neuroblastoma metastases
Growth lines
Frayed Metaphyses
mnemonic: | CHARMS |
Congenital infections (rubella, syphilis)
Hypophosphatasia
Achondroplasia
Rickets
Metaphyseal dysostosis
Scurvy
Bone tumor
Role of Radiologist
Is there a lesion?
Is it a bone tumor?
Is the tumor benign or malignant?
Is a biopsy necessary?
Is the histologic diagnosis consistent with the radiographic image?
Assessment of Aggressiveness
BENIGN
Diagnosis certain: no further work-up necessary
Asymptomatic lesion with highly probable benign diagnosis may be followed clinically
Symptomatic lesion with highly probable benign diagnosis may be treated without further work-up
CONFUSING LESION
not clearly categorized as benign or malignant; needs staging work-up
MALIGNANT: needs staging work-up
Staging work-up: Bone scan: identifies polyostotic lesions (eg, multiple myeloma, metastatic disease, primary osteosarcoma with bone-forming metastases, histiocytosis, Paget disease) Chest CT: identifies metastatic deposits + changes further work-up and therapy
Local staging with MR imaging:
Margins: encapsulated / infiltrating
Compartment: intra- / extracompartmental
Intraosseous extent + skip lesions
Soft-tissue extent (DDx: hematoma, edema)
Joint involvement
Neurovascular involvement
Local assessment with CT imaging:
matrix / rim calcifications
Tumorlike Conditions
Solitary bone cyst
Juxtaarticular ( synovial ) cyst
Aneurysmal bone cyst
Nonossifying fibroma; cortical defect; cortical desmoid
Eosinophilic granuloma
Reparative giant cell granuloma
Fibrous dysplasia (monostotic; polyostotic)
Myositis ossificans
Brown tumor of hyperparathyroidism
Massive osteolysis
Pseudomalignant Appearance
Osteomyelitis
Aggressive osteoporosis
Pattern of Bone Destruction
GEOGRAPHIC BONE DESTRUCTION
P.6
Cause: (a) slow-growing usually benign tumor (b)rarely malignant: plasma cell myeloma, metastasis
(c) infection: granulomatous osteomyelitis
well-defined smooth / irregular margin short zone of transition
MOTH-EATEN BONE DESTRUCTION
Cause: (a) rapidly growing malignant bone tumor (b) osteomyelitis
less well defined / demarcated lesional margin longer zone of transition
mnemonic: H LEMMON Histiocytosis X
Lymphoma
Ewing sarcoma
Metastasis
Multiple myeloma
Osteomyelitis
Neuroblastoma
PERMEATIVE BONE DESTRUCTION
Cause: aggressive bone tumor with rapid growth potential (eg, Ewing sarcoma) poorly demarcated lesion imperceptibly merging with uninvolved bone long zone of transition
Size, Shape, and Margin of Bone Lesion
Primary malignant tumors are larger than benign tumors elongated lesion (= greatest diameter of >1.5 times the least diameter): Ewing sarcoma, histiocytic lymphoma, chondrosarcoma, angiosarcoma sclerotic margin (= reaction of host tissue to tumor)
Tumor Position in Transverse Plane
CENTRAL MEDULLARY LESION
Enchondroma
Solitary bone cyst
ECCENTRIC MEDULLARY LESION
Giant cell tumor
Osteogenic sarcoma, chondrosarcoma, fibrosarcoma
Chondromyxoid fibroma
CORTICAL LESION
Nonossifying fibroma
Osteoid osteoma
PERIOSTEAL / JUXTACORTICAL LESION
Juxtacortical chondroma / osteosarcoma
Osteochondroma
Parosteal osteogenic sarcoma
Tumor Position in Longitudinal Plane
EPIPHYSEAL LESION
Chondroblastoma (prior to closure of growth plate)
Intraosseous ganglion, subchondral cyst
Giant cell tumor (originating in metaphysis)
Clear cell chondrosarcoma
Fibrous dysplasia
Abscess
mnemonic: CAGGIE Chondroblastoma
Aneurysmal bone cyst
Giant cell tumor
Geode
Infection
Eosinophilic granuloma
[after 40 years of age throw out CEA and insert metastases / myeloma]
METAPHYSEAL LESION
Nonossifying fibroma (close to growth plate)
Chondromyxoid fibroma (abutting growth plate)
Solitary bone cyst
Osteochondroma
Brodie abscess
Osteogenic sarcoma, chondrosarcoma
DIAPHYSEAL LESION
Round cell tumor (eg, Ewing sarcoma)
Nonossifying fibroma
Solitary bone cyst
Aneurysmal bone cyst
Enchondroma
Osteoblastoma
Fibrous dysplasia
mnemonic: FEMALE Fibrous dysplasia
Eosinophilic granuloma
Metastasis
Adamantinoma
Leukemia, Lymphoma
Ewing sarcoma
Tumors Localizing to Hematopoietic Marrow
Metastases
Plasma cell myeloma
Ewing sarcoma
Histiocytic lymphoma
Diffuse Bone Marrow Abnormalities in Childhood
REPLACED BY TUMOR CELLS
metastatic disease
Neuroblastoma (in young child)
Lymphoma (in older child)
Rhabdomyosarcoma (in older child)
primary neoplasm
Leukemia
REPLACED BY RED CELLS
= Red cell hyperplasia = reconversion
severe anemia: sickle cell disease, thalassemia, hereditary spherocytosis
chronic severe blood loss
marrow replacement by neoplasia
treatment with granulocyte-macrophage colony stimulating factor
REPLACED BY FAT
Myeloid depletion = aplastic anemia
REPLACED BY FIBROUS TISSUE
Myelofibrosis
Age Incidence of Malignant Bone Tumors
80% of bone tumors are correctly determined on the basis of age alone!
P.7
Sarcomas by Age
mnemonic: | Every Other Runner Feels Crampy Pain On Moving |
Ewing sarcoma | 0 10 years |
Osteogenic sarcoma | 10 30 years |
Reticulum cell sarcoma | 20 40 years |
Fibrosarcoma | 20 40 years |
Chondrosarcoma | 40 50 years |
Parosteal sarcoma | 40 50 years |
Osteosarcoma | 60 70 years |
Metastases | 60 70 years |
Age Incidence of Malignant Bone Tumors
Age [years] | Tumor |
---|---|
0.1 | Neuroblastoma |
0.1 10 | Ewing tumor in tubular bones (diaphysis) |
10 30 | Osteosarcoma (metaphysis); Ewing tumor in flat bones |
30 40 | Reticulum cell sarcoma (similar histology to Ewing tumor); fibrosarcoma; malignant giant cell tumor (similar histology to fibrosarcoma); parosteal sarcoma; lymphoma |
>40 | Metastatic carcinoma; multiple myeloma; chondrosarcoma |
Round Cell Tumors
arise in midshaft osteolytic lesion reactive new bone formation no tumor new bone
mnemonic: | LEMON |
Leukemia, Lymphoma
Ewing sarcoma, Eosinophilic granuloma
Multiple myeloma
Osteomyelitis
Neuroblastoma
Malignancy with Soft-tissue Involvement
mnemonic: | My Mother Eats Chocolate Fudge Often |
Metastasis
Myeloma
Ewing sarcoma
Chondrosarcoma
Fibrosarcoma
Osteosarcoma
Tumor Matrix of Bone Tumors
Cartilage-forming Bone Tumors
centrally located ringlike / flocculent / flecklike radiodensities
BENIGN
Enchondroma
Parosteal chondroma
Chondroblastoma
Average Age for Occurrence of Benign and Malignant Bone Tumors
Chondromyxoid fibroma
Osteochondroma
P.8
MALIGNANT
Chondrosarcoma
Chondroblastic osteosarcoma
Bone-forming Tumors
inhomogeneous / homogeneous radiodense collections of variable size + extent
BENIGN
Osteoma
Osteoid osteoma
Osteoblastoma
Ossifying fibroma
MALIGNANT
Osteogenic sarcoma
Fibrous Connective Tissue Tumors
BENIGN FIBROUS BONE LESIONS
cortical
Benign cortical defect
Avulsion cortical irregularity
medullary
Herniation pit
Nonossifying fibroma
Ossifying fibroma
Congenital generalized fibromatosis
corticomedullary
Nonossifying fibroma
Ossifying fibroma
Fibrous dysplasia
Cherubism
Desmoplastic fibroma
Fibromyxoma
MALIGNANT
Fibrosarcoma
Tumors of Histiocytic Origin
LOCALLY AGGRESSIVE
Giant cell tumor
Benign fibrous histiocytoma
MALIGNANT
Malignant fibrous histiocytoma
Tumors of Fatty Tissue Origin
BENIGN
Intraosseous lipoma
Parosteal lipoma
MALIGNANT
Intraosseous liposarcoma
Lipomas follow the signal intensity of subcutaneous fat in all sequences!
Tumors of Vascular Origin
<1% of all bone tumors
BENIGN
Hemangioma
Glomus tumor
Lymphangioma
Cystic angiomatosis
Hemangiopericytoma
MALIGNANT
Malignant hemangiopericytoma
Angiosarcoma = hemangioendothelioma
Metastatic sites: | lung, brain, lymph nodes, other bones |
Tumors of Neural Origin
BENIGN
Solitary neurofibroma
Neurilemoma
MALIGNANT
Neurogenic sarcoma = malignant schwannoma
Intraosseous lesion
Bubbly Bone Lesion
mnemonic: | FOGMACHINES |
Fibrous dysplasia, Fibrous cortical defect
Osteoblastoma
Giant cell tumor
Myeloma (plasmacytoma), Metastases from kidney, thyroid, breast
Aneurysmal bone cyst / Angioma
Chondromyxoid fibroma, Chondroblastoma
Histiocytosis X, Hyperparathyroid brown tumor, Hemophilia
Infection (Brodie abscess, Echinococcus, coccidioidomycosis)
Nonossifying fibroma
Enchondroma, Epithelial inclusion cyst
Simple unilocular bone cyst
Infectious Bubbly Lesion
Brodie abscess (Staph. aureus)
Coccidioidomycosis
Echinococcus
Atypical mycobacterium
Cystic tuberculosis
Blowout Lesion
METASTASES
Carcinoma of thyroid, kidney, breast
PRIMARY BONE TUMOR
Fibrosarcoma
Multiple myeloma (sometimes)
Aneurysmal bone cyst
Hemophilic pseudotumor
Nonexpansile Unilocular Well-demarcated Bone Defect
Fibrous cortical defect
Nonossifying fibroma
Simple unicameral bone cyst
Giant cell tumor
Brown tumor of HPT
Eosinophilic granuloma
Enchondroma
Epidermoid inclusion cyst
Posttraumatic / degenerative cyst
Pseudotumor of hemophilia
Intraosseous ganglion
Histiocytoma
Arthritic lesion
Endosteal pigmented villonodular synovitis
Fibrous dysplasia
Infectious lesion
P.9
Nonexpansile Multilocular Well-demarcated Bone Defect
Aneurysmal bone cyst
Giant cell tumor
Fibrous dysplasia
Simple bone cyst
Expansile Unilocular Well-demarcated Osteolysis
Simple unicameral bone cyst
Enchondroma
Aneurysmal bone cyst
Juxtacortical chondroma
Nonossifying fibroma
Eosinophilic granuloma
Brown tumor of HPT
Poorly Demarcated Osteolytic Lesion without Periosteal Reaction
NONEXPANSILE
Metastases from any primary neoplasm
Multiple myeloma
Hemangioma
EXPANSILE
Chondrosarcoma
Giant cell tumor
Metastasis from kidney / thyroid
Poorly Demarcated Osteolytic Lesion with Periosteal Reaction
Osteomyelitis
Ewing sarcoma
Osteosarcoma
Mixed Sclerotic and Lytic Lesion
Mixed Bone Lesion with Button Sequestrum
bone opacity surrounded by a well-defined lucent area common:
Osteomyelitis
Eosinophilic granuloma
Fibrosarcoma, desmoplastic fibroma, MFH
Lymphoma
uncommon:
partially calcified intraosseous lipoma, tuberculous osteitis, radiation necrosis, metastatic carcinoma, fibrous dysplasia, dermoid & epidermoid cyst, hemangioma, meningioma
Mixed Bone Lesion without Sequestrum
Osteomyelitis
Tuberculosis
Ewing sarcoma
Metastasis
Osteosarcoma
Trabeculated Bone Lesion
1. Giant cell tumor: | delicate thin trabeculae |
2. Chondromyxoid fibroma: | coarse thick trabeculae |
3. Nonossifying fibroma: | lobulated |
4. Aneurysmal bone cyst: | delicate, horizontally oriented trabeculae |
5. Hemangioma: | striated radiating trabeculae |
Lytic Bone Lesion Surrounded by Marked Sclerosis
mnemonic: | BOOST |
Brodie abscess
Osteoblastoma
Osteoid osteoma
Stress fracture
Tuberculosis
Multiple Lytic Lesions
mnemonic: | FEEHMI |
Fibrous dysplasia
Enchondromas
Eosinophilic granuloma
Hyperparathyroidism (brown tumors), Hemangiomas
Metastases, Multiple myeloma
Infection
Multiple Lytic Lesions in Child
Histiocytosis X
Metastatic neuroblastoma / leukemia
Fibrous dysplasia
Enchondromatosis
Rare: cystic angiomatosis, multifocal osteomyelitis
Lytic Bone Lesion in Patient <30 Years of Age
mnemonic: | CAINES |
Chondroblastoma
Aneurysmal bone cyst
Infection
Nonossifying fibroma
Eosinophilic granuloma
Solitary bone cyst
Lytic Bone Lesion on Both Sides of Joint
mnemonic: | SAC |
Synovioma
Angioma
Chondroid lesion
Multiple Bone Lesions & Soft-tissue Tumor
Neurofibromatosis & fibroxanthomas
Maffucci syndrome = enchondromatosis & hemangioma
Mazabraud syndrome = fibrous dysplasia & myxoma
Metastases
Multiple myeloma
Malignant melanoma
Lymphoma
Osteoblastic Bone Lesion
BENIGN
Bone island
Osteoma
Osteoid osteoma
MALIGNANT
Osteosarcoma
Parosteal sarcoma
P.10
Widespread Osteosclerotic Lesions
Metastases: prostate, breast, lung, bladder, pancreas, stomach, colon, carcinoid, brain
Paget disease
Sarcoma
Myelofibrosis
Mastocytosis
Dwarfism
Classification:
OSTEOCHONDRODYSPLASIA
= abnormalities of cartilage / bone growth and development
identifiable at birth:
usually lethal: achondrogenesis, fibrochondrogenesis, thanatophoric dysplasia, short rib syndrome
usually nonlethal: chondrodysplasia punctata, camptomelic dysplasia, achondroplasia, diastrophic dysplasia, chondroectodermal dysplasia, Jeune syndrome, spondyloepiphyseal dysplasia congenita, mesomelic dysplasia, cleidocranial dysplasia, oto-palato-digital syndrome
identifiable in later life: hypochondroplasia, dyschondrosteosis, spondylometaphyseal dysplasia, acromicric dysplasia
abnormal bone density: osteopetrosis, pyknodysostosis, Melnick-Needles syndrome
DYSOSTOSIS
= malformation of individual bones singly / in combination
with cranial + facial involvement:craniosynostosis, craniofacial dysostosis (Crouzon), acrocephalosyndactyly, acrocephalopolysyndactyly, branchial arch syndromes (Treacher-Collins, Franceschetti, acrofacial dysostosis, oculo-auriculo-vertebral dysostosis, hemifacial microsomia, oculo-mandibulo-facial syndrome
with predominant axial involvement:vertebral segmentation defects (Klippel-Feil), Sprengel anomaly, spondylocostal dysostosis, oculovertebral syndrome
with predominant involvement of extremities:acheiria (= absence of hands), apodia (= absence of feet), polydactyly, syndactyly, camptodactyly, Rubinstein-Taybi syndrome, pancytopenia-dysmelia syndrome (Fanconi), Blackfan-Diamond anemia with thumb anomaly, thrombocytopenia-radial aplasia syndrome, cardiomelic syndromes (Holt-Oram), focal femoral deficiency, multiple synostoses
IDIOPATHIC OSTEOLYSIS
= disorders with multifocal resorption of bone
CHROMOSOMAL ABERRATION
PRIMARY METABOLIC DISORDER
(a) calcium / phosphorus: hypophosphatasia (b) complex carbohydrates: mucopolysaccharidosis
Terminology:
Micromelia | = | shortening involves entire limb (eg, humerus, radius + ulna, hand) |
Rhizomelia | = | shortening involves proximal segment (eg, humerus) |
Mesomelia | = | shortening involves intermediate segment (eg, radius + ulna) |
Acromelia | = | shortening involves distal segment (eg, hand) |
Micromelic Dwarfism
= disproportionate shortening of entire leg
Mild micromelic dwarfism
Jeune syndrome
Ellis-van Creveld syndrome= chondroectodermal dysplasia
Diastrophic dwarfism
Mild bowed micromelic dwarfism
Camptomelic dysplasia
Osteogenesis imperfecta, type III
Severe micromelic dwarfism
Thanatophoric dysplasia
Osteogenesis imperfecta, type II
Homozygous achondroplasia
Hypophosphatasia
Short-rib polydactyly syndrome
Fibrochondrogenesis
Acromelic Dwarfism
= distal shortening (hands, feet)
Asphyxiating thoracic dysplasia
Rhizomelic Dwarfism
= shortening of proximal segments (humerus, femur)
mnemonic: | MA CAT |
Metatrophic dwarfism
Achondrogenesis (most severe shortening)
Chondrodysplasia punctata (autosomal recessive)
Achondroplasia, heterozygous
Thanatophoric dysplasia
Osteochondrodysplasia
Failure of
articular cartilage: spondyloepiphyseal dysplasia
ossification center: multiple epiphyseal dysplasia
proliferating cartilage: achondroplasia
spongiosa formation: hypophosphatasia
spongiosa absorption: osteopetrosis
periosteal bone: osteogenesis imperfecta
endosteal bone: idiopathic osteoporosis
Excess of
articular cartilage: dysplasia epiphysealis hemimelica
hypertrophic cartilage: enchondromatosis
spongiosa: multiple exostosis
periosteal bone: progressive diaphyseal dysplasia
endosteal bone: hyperphosphatemia
Lethal Bone Dysplasia
in order of frequency:
Thanatophoric dysplasia
Osteogenesis imperfecta type II
Achondrogenesis type I + II
Jeune syndrome (may be nonlethal)
Hypophosphatasia, congenital lethal form
Chondroectodermal dysplasia (usually nonlethal)
Chondrodysplasia punctata, rhizomelic type
Camptomelic dysplasia
Short-rib polydactyly syndrome
Homozygous achondroplasia
Lethal short-limbed dysplasias typically are manifest on sonograms before 24 weeks MA!
P.11
Nonlethal Dwarfism
Achondroplasia (heterozygous)
Asphyxiating thoracic dysplasia
Chondroectodermal dysplasia
Chondrodysplasia punctata
Spondyloepiphyseal dysplasia (congenital)
Diastrophic dwarfism
Metatrophic dwarfism
Hypochondroplasia
Late-onset Dwarfism
Spondyloepiphyseal dysplasia tarda
Multiple epiphyseal dysplasia
Pseudoachondroplasia
Metaphyseal chondrodysplasia
Dyschondrosteosis
Cleidocranial dysostosis
Progressive diaphyseal dysplasia
Hypomineralization in Fetus
DIFFUSE
Osteogenesis imperfecta
Hypophosphatasia
SPINE
Achondrogenesis
Large Head in Fetus
Achondroplasia
Thanatophoric dysplasia
Narrow Chest in Fetus
Short-rib polydactyly syndrome
Asphyxiating thoracic dysplasia
Chondroectodermal dysplasia
Camptomelic dysplasia
Thanatophoric dwarfism
Homozygous achondroplasia
Achondrogenesis
Hypophosphatasia
Platyspondyly
Thanatophoric dysplasia
Osteogenesis imperfecta type II
Achondroplasia
Morquio syndrome
Bowed Long Bones in Fetus
Camptomelic syndrome
Osteogenesis imperfecta
Thanatophoric dysplasia
Hypophosphatasia
Bone Fractures in Fetus
Osteogenesis imperfecta
Hypophosphatasia
Achondrogenesis
Limb reduction anomalies
Amelia | = | absence of limb |
Hemimelia | = | absence of distal parts |
Phocomelia | = | proximal reduction with distal parts attached to trunk |
Aplasia / Hypoplasia of Radius
mnemonic: | The Furry Cat Hit My Dog |
Thrombocytopenia absent radius syndrome
Fanconi anemia
Cornelia de Lange syndrome
Holt-Oram syndrome
Myositis ossificans progressiva (thumb only)
Diastrophic dwarfism ( hitchhiker's thumb )
Pubic Bone Maldevelopment
mnemonic: | CHIEF |
Cleidocranial dysostosis
Hypospadia, epispadia
Idiopathic
Exstrophy of bladder
F for syringomyelia
Bone overgrowth
Bone Overdevelopment
Marfan syndrome
Klippel-Trenaunay syndrome
Nerve territory-oriented macrodactyly
Macrodystrophia lipomatosa
Fibrolipomatous hamartoma with macrodactyly
Erlenmeyer Flask Deformity
= expansion of distal end of long bones, usually femur
Gaucher disease, Niemann-Pick disease
Hemolytic anemia: thalassemia, sickle cell
Osteopetrosis
Heavy metal poisoning
Metaphyseal dysplasia = Pyle disease
Rickets
Fibrous dysplasia
Down syndrome
Achondroplasia
Rheumatoid arthritis
Hypophosphatasia
Leukemia
mnemonic: | TOP DOG |
Thalassemia
Osteopetrosis
Pyle disease
Diaphyseal aclasis
Ollier disease
Gaucher disease
P.12
Periosteal reaction / periostitis
1. Trauma, hemophilia | |
2. Infection | |
3. Inflammatory: | arthritis |
4. Neoplasm | |
5. Congenital: | physiologic in newborn |
6. Metabolic: | hypertrophic osteoarthropathy, thyroid acropachy, hypervitaminosis A |
7. Vascular: | venous stasis |
Solid Periosteal Reaction
= reaction to periosteal irritant
even + uniform thickness >1 mm persistent + unchanged for weeks
Patterns:
thin: eosinophilic granuloma, osteoid osteoma
dense undulating: vascular disease
thin undulating: pulmonary osteoarthropathy
dense elliptical: osteoid osteoma; long-standing malignant disease (with destruction)
cloaking: storage disease; chronic infection
Interrupted Periosteal Reaction
= pleomorphic, rapidly progressing process undergoing constant change
buttressing = periosteal bone formation merges with underlying cortex: eosinophilic granuloma
laminated = onion skin : acute osteomyelitis; malignant tumor (osteosarcoma, Ewing sarcoma)
radiating spicules = sunburst : osteosarcoma; Ewing sarcoma; chondrosarcoma; fibrosarcoma; leukemia; metastasis; acute osteomyelitis
perpendicular spicules = hair-on-end : Ewing sarcoma
amorphous: malignancy (deposits may represent extension of tumor / periosteal response); osteosarcoma
Codman triangle: hemorrhage; malignancy (osteosarcoma, Ewing sarcoma); acute osteomyelitis; fracture
Symmetric Periosteal Reaction in Adulthood
Venous stasis (lower extremity)
Hypertrophic osteoarthropathy
Pachydermoperiostosis
Thyroid acropachy
Fluorosis
Rheumatoid arthritis
Psoriatic arthritis
Reiter syndrome
Idiopathic-degenerative
Periosteal Reaction in Childhood
benign
Physiologic (up to 35%): symmetric involvement of diaphyses during first 1 6 months of life
Nonaccidental trauma = battered child syndrome
Infantile cortical hyperostosis: <6 months of age
Hypervitaminosis A
Scurvy
Osteogenesis imperfecta
Congenital syphilis
malignant
Multicentric osteosarcoma
Metastases from neuroblastoma + retinoblastoma
Acute leukemia
mnemonic: | PERIOSTEAL SOCKS |
Physiologic, Prostaglandin
Eosinophilic granuloma
Rickets
Infantile cortical hyperostosis
Osteomyelitis
Scurvy
Trauma
Ewing sarcoma
A-hypervitaminosis
Leukemia + neuroblastoma
Syphilis
Osteosarcoma
Child abuse
Kinky hair syndrome
Sickle cell disease
Periosteal Reaction in Infant
before 6 months of age
Infantile cortical hyperostosis
Physiologic
Extracorporeal membrane oxygenation
after 6 months of age
Hypervitaminosis A
Scurvy
Rickets
anytime during infancy
Nonaccidental trauma
Syphilis
Metastatic neuroblastoma / leukemia
Prostaglandin therapy: within 40 days
Sickle cell dactylitis
DDx: | motion artifact |
Enthesopathy
[en, Greek = in; thesis, Greek = position]
Enthesis = osseous attachment of tendon composed of 4 zones, ie, tendon itself + unmineralized fibrocartilage + mineralized fibrocartilage + bone
Cause:
Degenerative disorder
Seronegative arthropathies: ankylosing spondylitis, Reiter disease, psoriatic arthritis
Diffuse idiopathic skeletal hyperostosis
Acromegaly
Rheumatoid arthritis (occasionally)
Location: | at site of tendon + ligament attachment |
bone proliferation (enthesophyte) calcification of tendon + ligament erosion
Bone trauma
Childhood Fractures
Greenstick fracture
Bowing fracture
Traumatic epiphyseolysis
Battered child syndrome
Epiphyseal plate injury
P.13
Pseudarthrosis in Long Bones
Nonunion of fracture
Fibrous dysplasia
Neurofibromatosis
Osteogenesis imperfecta
Congenital: clavicular pseudarthrosis
Exuberant Callus Formation
Steroid therapy / Cushing syndrome
Neuropathic arthropathy
Osteogenesis imperfecta
Congenital insensitivity to pain
Paralysis
Renal osteodystrophy
Multiple myeloma
Battered child syndrome
Epiphysis
Premature Epiphyseal Ossification
@ Proximal femoral and humeral epiphyses
Jeune asphyxiating thoracic dysplasia
Ellis-van Creveld chondroectodermal dysplasia
Epiphyseal / Apophyseal Lesion
Chondroblastoma
Brodie abscess
Fungal / tuberculous infection
Langerhans cell histiocytosis
Osteoid osteoma
Chondromyxoid fibroma
Enchondroma
Bone cyst
Foreign-body granuloma
Subarticular Lesion
Giant cell tumor
Solitary subchondral cyst
Intraosseous ganglion
Brodie abscess
Clear cell chondrosarcoma
Stippled Epiphyses
Normal variant
Avascular necrosis
Hypothyroidism
Chondrodysplasia punctata
Multiple epiphyseal dysplasia
Spondyloepiphyseal dysplasia
Hypoparathyroidism
Down syndrome
Trisomy 18
Fetal warfarin syndrome
Homocystinuria (distal radial + ulnar epiphyses = pathognomonic)
Zellweger cerebrohepatorenal syndrome
Physeal / Metaphyseal Widening & Irregularity
Rickets
Hypophosphatasia
Metaphyseal chondroplasia
Epiphyseal Overgrowth
Juvenile rheumatoid arthritis
Hemophilia
Healed Legg-Perthes disease
Tuberculous arthritis
Pyogenic arthritis (chronic)
Fungal arthritis
Epiphyseal dysplasia hemimelica
Fibrous dysplasia of epiphysis
Winchester syndrome
Epiphyseolysis
= SLIPPED EPIPHYSIS(zone of maturing hypertrophic cartilage affected, not zone of proliferation)
Idiopathic / juvenile epiphyseolysis
Age: 12 15 years (? puberty-related hormonal dysregulation) adiposogenital type; tall stature
Renal osteodystrophy
Hyperparathyroidism in chronic renal disease
Hypothyroidism
Radiotherapy
Joints
Approach to Arthritis
mnemonic: | ABCDE'S |
Alignment
Bone mineralization
Cartilage loss
Distribution
Erosion
Soft tissues
Signs of Arthritis
Prevalence of arthritis: | 15% of population in USA |
Conventional x-ray:
narrowing of radiologic joint space: uniform = inflammatory arthritis
nonuniform = degenerative arthritis
evidence of disease on both sides of joint: osteopenia subchondral sclerosis erosion subchondral cyst formation malalignment
joint effusion joint bodies
NUC:
increase in regional blood flow (active disease) distribution of disease
MR:
irregularity + narrowing of articular cartilage Gd-DTPA enhancement of synovium (active disease)
P.14
Classification of Arthritides
SEPTIC ARTHRITIS
Tuberculous
Pyogenic
Lyme arthritis
Fungal arthritis: Candida, Coccidioides immitis, Blastomyces dermatitidis, Histoplasma capsulatum, Sporothrix schenckii, Cryptococcus neoformans, Aspergillus fumigatus
N.B.: Tuberculous + fungal arthritis shows prominent osteoporosis + slower rate of destruction + less joint narrowing than a pyogenic infection (Phemister triad)
COLLAGEN / COLLAGEN-LIKE DISEASE
Rheumatoid arthritis
Ankylosing spondylitis
Psoriatic arthritis
Rheumatic fever
Sarcoidosis
BIOCHEMICAL ARTHRITIS
Gout
Chondrocalcinosis
Ochronosis
Hemophilic arthritis
DEGENERATIVE JOINT DISEASE = Osteoarthritis
TRAUMATIC
Secondary osteoarthritis
Neurotrophic arthritis
Pigmented villonodular synovitis
ENTEROPATHIC ARTHROPATHY
INFLAMMATORY BOWEL DISEASE
Ulcerative colitis (in 10 20%)
Crohn disease (in 5%): peripheral arthritis increases with colonic disease
Whipple disease (in 60 90% transient intermittent polyarthritis: sacroiliitis, spondylitis)
Resection of diseased bowel is associated with regression of arthritic symptomatology!
INFECTIOUS BOWEL DISEASE
Infectious agents: Salmonella, Shigella, Yersinia
after intestinal bypass surgery
Spondyloarthritis and Positive HLA-B 27 Histocompatibility Complex
1. Ankylosing spondylitis | 95% |
2. Reiter disease | 80% |
3. Arthropathy of inflammatory bowel disease | 75% |
4. Psoriatic spondylitis | 70% |
5. Normal population | 10% |
Monoarthritis
Destructive Monoarthritis
Any destructive monoarthritis should be regarded as infection until proved otherwise!
Septic arthritis
Monoarticular presentation of a systemic arthritis
Rheumatoid arthritis
Gout
Amyloidosis
Seronegative arthritis
Joint tumor
PVNS
Synovial chondromatosis
Articular hemangioma
Nonseptic Monoarthritis
Gout
Milwaukee shoulder
Rapidly destructive articular disease
Amyloid arthropathy
Hemophilic arthropathy
Primary synovial osteochondromatosis
Pigmented villonodular synovitis
Neuropathic arthropathy
Foreign-body synovitis
Arthritis without Demineralization
Gout
Neuropathic arthropathy
Psoriasis
Reiter disease
Pigmented villonodular synovitis
mnemonic: | PONGS |
Psoriatic arthritis
Osteoarthritis
Neuropathic joint
Gout
Sarcoidosis
Arthritis with Demineralization
mnemonic: | HORSE |
Hemophilia
Osteomyelitis
Rheumatoid arthritis, Reiter disease
Scleroderma
Erythematosus, systemic lupus
Deforming Nonerosive Arthropathy
Collagen-vascular disease, especially SLE
Rheumatoid arthritis (rare)
Rheumatic fever (Jaccoud arthritis) (rare)
Arthritis with Periostitis
Juvenile rheumatoid arthritis
Psoriatic arthritis
Reiter syndrome
Infectious arthritis
Premature Osteoarthritis
mnemonic: | COME CHAT |
Calcium pyrophosphate dihydrate arthropathy
Ochronosis
Marfan syndrome
Epiphyseal dysplasia
Charcot joint = neuroarthropathy
Hemophilic arthropathy
Acromegaly
Trauma
Synovial Disease with Decreased Signal Intensity
= hemosiderin deposition
P.15
Pigmented villonodular synovitis
Rheumatoid arthritis
Hemophilia
Chondrocalcinosis
mnemonic: | WHIP A DOG |
Wilson disease
Hemochromatosis, Hemophilia, Hypothyroidism, 1 Hyperparathyroidism (15%), Hypophosphatasia, Familial Hypomagnesemia
Idiopathic (aging)
Pseudogout (CPPD)
Arthritis (rheumatoid, postinfectious, traumatic, degenerative), Amyloidosis, Acromegaly
Diabetes mellitus
Ochronosis
Gout
mnemonic: | 3 C's |
Crystals | CPPD, sodium urate (gout) |
Cations | calcium (any cause of hypercalcemia), copper, iron |
Cartilage degeneration | osteoarthritis, acromegaly, ochronosis |
Subchondral Cyst
= SYNOVIAL CYST = SUBARTICULAR PSEUDOCYST
= NECROTIC PSEUDOCYST = GEODES
Etiology: bone necrosis allows pressure-induced intrusion of synovial fluid into subchondral bone; in conditions with synovial inflammation Cause: 1. Osteoarthritis 2. Rheumatoid arthritis
3. Osteonecrosis
4. CPPD
size of cyst usually 2 35 mm may be large + expansile (especially in CPPD) DDx: (1) Giant cell tumor (2) Pigmented villonodular synovitis
(3)Metastasis
(4) Intraosseous ganglion
5) Hemophilia
Loose Intraarticular Bodies
Osteochondrosis dissecans
Synovial osteochondromatosis
Chip fracture from trauma
Severe degenerative joint disease
Neuropathic arthropathy
Intraarticular Process with Cortical Erosion
Pigmented villonodular synovitis
Synovial osteochondromatosis
Rheumatoid arthritis
Gout
Synovial hemangioma
Lipoma arborescens
Erosions of DIP Joints
Inflammatory osteoarthritis
Psoriatic arthritis
Gout
Multicentric reticulohistiocytosis
Hyperparathyroidism
Frostbite
Septic arthritis
Articular Disorders of Hand and Wrist
Osteoarthritis = degenerative joint disease
= abnormal stress with minor + major traumatic episodes
Target areas: DIP, PIP, 1st CMC, trapezioscaphoid; bilateral symmetric / asymmetric joint space narrowing subchondral eburnation marginal osteophytes + small ossicles radial subluxation of 1st metacarpal base Radiocarpal joint normal unless history of trauma
Erosive osteoarthritis = inflammatory osteoarthritis
Age: predominantly middle-aged / postmenopausal women acute inflammatory episodes
Target areas: DIP, PIP, 1st CMC, trapezioscaphoid; bilateral symmetric / asymmetric central erosions combined with osteophytes= subchondral gull wing erosions joint space narrowing + sclerosis rare ankylosis
Psoriatic arthritis
= rheumatoid variant / seronegative spondyloarthropathy; peripheral manifestation in monarthritis / asymmetric oligoarthritis / symmetric polyarthritis
Target areas: all hand + wrist joints (commonly distal); bi- / unilateral asymmetric polyarticular changes mouse ears marginal erosions intraarticular osseous excrescences new bone formation fusion osteoporosis may be absent
Rheumatoid arthritis
= synovial proliferative granulation tissue = pannus
Target areas: PIP (early in 3rd), MCP (earliest changes in 2nd + 3rd), all wrist joints (early in RC, IRU), ulnar styloid; both hands in relative symmetric fashion fusiform soft-tissue swelling regional periarticular osteoporosis diffuse loss of joint space marginal + central poorly defined erosions joint deformities
Gouty arthritis
monosodium urate crystals in synovial fluid
asymptomatic periods from months to years
Target areas: commonly CCMC + all hand joints
development of chronic tophaceous gout= lobulated soft-tissue masses well-defined eccentric erosions with overhanging edge (often periarticular) + sclerotic margins preservation of joint spaces absence of osteoporosis most extensive changes in common carpometacarpal compartment: P.16
scalloped erosions of bases of ulnar metacarpals
Calcium pyrophosphate dihydrate crystal deposition disease = CPPD
Target areas: MCP (2nd, 3rd), radiocarpal; bilateral symmetric / asymmetric changes chondrocalcinosis + periarticular calcifications: calcification of triangular fibrocartilage
degenerative changes in unusual locations: narrowing obliteration of space between distal radius and scaphoid fragmentation of surfaces scapholunate separation destruction of trapezioscaphoid space
no erosions + large osteophytes = hemochromatosis
SLE
= myositis, symmetric polyarthritis, deforming nonerosive arthropathy, osteonecrosis
Target areas: PIP, MCP reversible deformities
Scleroderma = progressive systemic sclerosis (PSS)
Target areas: DIP, PIP, 1st CMC tuft resorption soft-tissue calcifications
Arthritis Involving Distal Interphalangeal Joints
mnemonic: | POEM |
Psoriatic arthritis
Articulations of Hand and Wrist
Osteoarthritis
Erosive osteoarthritis
Multicentric reticulohistiocytosis
Ankylosis of Interphalangeal Joints
mnemonic: | S - Lesions |
Psoriatic arthritis
Ankylosing spondylitis
Erosive osteoarthritis
Still disease
Sacroiliitis
Joint anatomy:
ligamentous portion (superior 2/3 to 1/2 of joint):
formed by interosseous sacroiliac ligament
synovial component (inferior 1/3 to 1/2 of joint):
the sacral surface is lined by 3 5 mm-thick hyaline cartilage; the iliac surface of joint is lined by 1 mm-thick fibrocartilage
2 5 mm normal joint width
Positioning: oblique view + modified Ferguson view = AP projection with 23 cephalad angulation
findings predominate on the iliac side (thinner cartilage)
BILATERAL SYMMETRIC
Ankylosing spondylitis
small regular erosion = loss of definition of white cortical line on iliac side (initially) Distribution Pattern of Arthritic Lesions (adapted from Donald Resnick, M.D.)
subchondral sclerosis + subsequent ankylosis ossification of interosseous ligaments
P.17
Enteropathic arthropathy
same signs as in ankylosing spondylitis
Rheumatoid arthritis (in late stages)
joint space narrowing without reparation osteoporosis ankylosis may occur
Deposition arthropathy: gout, CPPD, ochronosis, acromegaly
slow loss of cartilage subchondral reparative bone + osteophytes
Osteitis condensans ilii
DDx: Hyperparathyroidism (subchondral bone resorption on iliac side resembling erosion + widening of joint) BILATERAL ASYMMETRIC
Psoriatic arthritis
large extensive erosion subchondral sclerosis + occasional ankylosis
Reiter syndrome
Juvenile rheumatoid arthritis
UNILATERAL
Infection
Osteoarthritis from abnormal mechanical stress
no erosions irregular narrowing of joint space with subchondral sclerosis osteophytes at anterosuperior / -inferior aspect of joint (may resemble ankylosis)
DDx: psoriatic arthritis, Reiter syndrome, trauma, gout, pigmented villonodular synovitis, osteitis condensans ilii
Sacroiliac Joint Widening
mnemonic: | CRAP TRAP |
Colitis
Rheumatoid arthritis
Abscess (infection)
Parathyroid disease
Trauma
Reiter syndrome
Ankylosing spondylitis
Psoriasis
Sacroiliac Joint Fusion
mnemonic: | CARPI |
Colitic spondylitis
Ankylosing spondylitis
Reiter syndrome
Psoriatic arthritis
Infection (TB)
Widened Symphysis Pubis
mnemonic: | EPOCH |
Exstrophy of the bladder
Prune belly syndrome
Osteogenesis imperfecta
Cleidocranial dysostosis
Hypothyroidism
Arthritis of Interphalangeal Joint of Great Toe
Psoriatic arthritis
Reiter disease
Gout
Degenerative joint disease
Ribs
Thoracic Deformity
Funnel Chest = Pectus Excavatum
= posterior depression of sternum compressing heart against spine
Most frequently an isolated anomaly!
May be associated with:
prematurity, homocystinuria, Marfan syndrome, Noonan syndrome, fetal alcohol syndrome
depressed position of sternum (LATERAL) indistinct right heart border mimicking right middle lobe process (FRONTAL) decreased heart density (FRONTAL) leftward displacement of heart mimicking cardiomegaly (FRONTAL) horizontal course of posterior portion of ribs accentuated downward course of anterior portions of ribs (FRONTAL)
Barrel Chest
= large sagittal diameter of thorax
Cause: COPD, emphysema lateral segments of ribs elongated + straight pointing vertical (FRONTAL) square shape on cross section (CT)
Congenital Rib Anomalies
Prevalence: | 1.4% |
Cervical rib (0.2 1 8%)
M<F
usually asymptomatic
thoracic outlet syndrome (due to elevation of floor of scalene triangle with decrease of costoclavicular space):
Differential Diagnosis of Sacroiliac Joint Disease
Osteoarthritis Ankylosing spondylitis ilii Osteitis condensans Age older younger younger Sex M, F M > F F > M Distribution bi- / unilateral symmetric bilateral symmetric bilateral Sclerosis iliac mild focal iliac extensive iliac triangular Erosions absent common absent Intraarticular ankylosis rare common absent Ligamentous ossification less common common absent P.18
10 20% of symptomatic patients have a responsible cervical rib 5 10% of complete cervical ribs cause symptoms
May be associated with: Klippel-Feil anomaly
uni- / bilateral may fuse with first ribs anteriorly adjacent transverse process angulated inferiorly Cx: aneurysmal dilatation of subclavian a. DDx: elongated transverse process of 7th cervical vertebra; hypoplastic 1st thoracic rib
Forked / bifid rib (0.6%) = duplication of anterior portion
Location: 4th rib (most often) May be associated with: Gorlin basal cell nevus syndrome A single bifid rib is most commonly a normal incidental finding!
Rib fusion (0.3%)
May be associated with: vertebral segmentation anomalies Location: 1st + 2nd rib / several adjacent ribs Site: posterior / anterior portion Bone bridging = focal joining by bone outgrowth
Cause: congenital / posttraumatic Location: anywhere along one pair of ribs / several adjacent ribs complete bridging / pseudarthrosis
Rudimentary / hypoplastic rib (0.2%)
Location: 1st rib (usually) transverse process angulated superiorly DDx: cervical rib
Pseudarthrosis of 1st rib (0.1%)
radiolucent line through midportion with dense sclerotic borders
Intrathoracic / pelvic rib (rare)
Abnormal number of ribs
supernumerary: trisomy 21, VATER syndrome
11 pairs: normal individuals (5 8%); trisomy 21 (33%); cleidocranial dysplasia; camptomelic dysplasia
Short Ribs
Thanatophoric dysplasia
Jeune asphyxiating thoracic dysplasia
Ellis-van Creveld chondroectodermal dysplasia
Short rib-polydactyly syndromes (Saldino-Noonan, Majewski, Verma-Naumoff)
Achondroplasia
Achondrogenesis
Mesomelic dwarfism
Spondyloepiphyseal dysplasia
Enchondromatosis
Rib Lesions
BENIGN RIB TUMOR
Fibrous dysplasia (most common benign lesion)
predominantly posterior location
Osteochondroma / exostosis: at costochondral / costovertebral junction
Associated with: spontaneous hemothorax Langerhans cell histiocytosis (eosinophilic granuloma)
Benign cortical defect
Hemangioma of bone
Enchondroma: at costochondral / costovertebral junction
Giant cell tumor
Aneurysmal bone cyst
Osteoblastoma
Osteoid osteoma
Chondroblastoma
Enostosis = bone island (0.4%)
Paget disease
Brown tumor of HPT
Xanthogranuloma
PRIMARY MALIGNANT RIB TUMOR
Chondrosarcoma (calcified matrix): most common
Plasmacytoma
Lymphoma
Osteosarcoma (rare)
Fibrosarcoma
Primitive neuroectodermal tumor (= Askin tumor)
SECONDARY MALIGNANT RIB TUMOR
in adult: 1. Metastasis (most common malignant lesion) 2. Multiple myeloma
3. Desmoid tumor
in child: 1. Ewing sarcoma (most common malignant tumor affecting ribs of children + adolescents) 2. Metastatic neuroblastoma
TRAUMATIC RIB DISORDER
Healing fracture
Radiation osteitis
DDx: pulmonary nodule
AGGRESSIVE GRANULOMATOUS INFECTIONS
= osteomyelitis
Expansile Rib Lesion
mnemonic: | O FEEL THE CLAMP |
Osteochondroma (25% of all benign rib tumors)
Fibrous dysplasia
Eosinophilic granuloma
Enchondroma (7% of all benign rib tumors)
Lymphoma / Leukemia
Tuberculosis
Hematopoiesis
Ewing sarcoma
Chondromyxoid fibroma
Lymphangiomatosis
Aneurysmal bone cyst
Metastases
Plasmacytoma
Abnormal Rib Shape
Rib Notching on Inferior Margin
= minimal concave scalloping / deep ridges along the neurovascular groove with reactive sclerosis
Minor undulations in the inferior ribs are normal! The medial third of posterior ribs near transverse process of vertebrae may be notched normally! P.19
ARTERIAL
Cause: intercostal aa. function as collaterals to descending aorta / lung Aorta: coarctation (usually affects ribs 4 8; rare before age 8 years), thrombosis
Subclavian artery: Blalock-Taussig shunt
Pulmonary artery: pulmonary stenosis, tetralogy of Fallot, absent pulmonary artery
VENOUS
Cause: enlargement of intercostal veins AV malformation of chest wall
Superior vena cava obstruction
NEUROGENIC
Intercostal neuroma
Neurofibromatosis type 1
Poliomyelitis / quadriplegia / paraplegia
OSSEOUS
Hyperparathyroidism
Thalassemia
Melnick-Needles syndrome
Unilateral Rib Notching on Inferior Margin
Postoperative Blalock-Taussig shunt(subclavian to pulmonary artery)
Coarctation between origin of innominate a. + L subclavian a.
Coarctation proximal to aberrant subclavian a.
Rib Notching on Superior Margin
Rheumatoid arthritis
Scleroderma
Systemic lupus erythematosus
Hyperparathyroidism
Restrictive lung disease
Marfan syndrome
Dysplastic Twisted Ribbon Ribs
Osteogenesis imperfecta
Neurofibromatosis
Bulbous Enlargement of Costochondral Junction
Rachitic rosary
Scurvy
Achondroplasia
Hypophosphatasia
Metaphyseal chondrodysplasia
Acromegaly
Wide Ribs
Marrow hyperplasia (anemias)
Fibrous dysplasia
Paget disease
Achondroplasia
Mucopolysaccharidoses
Slender Ribs
Trisomy 18 syndrome
Neurofibromatosis
Dense Ribs
Tuberous sclerosis
Osteopetrosis
Mastocytosis
Fluorosis
Fibrous dysplasia
Chronic infection
Trauma
Subperiosteal rib resection
Hyperlucent Ribs
Congenitally Lucent Ribs
Osteogenesis imperfecta
Achondrogenesis
Hypophosphatasia
Camptomelic dysplasia
Acquired Lucent Ribs
Cushing disease
Acromegaly
Scurvy
Clavicle
Absence of Outer End of Clavicle
Rheumatoid arthritis
Hyperparathyroidism
Posttraumatic osteolysis
Metastasis / multiple myeloma
Cleidocranial dysplasia
Gorlin basal cell nevus syndrome
Penciled Distal End of Clavicle
mnemonic: | SHIRT Pocket |
Scleroderma
Hyperparathyroidism
Infection
Rheumatoid arthritis
Trauma
Progeria
Destruction of Medial End of Clavicle
mnemonic: | MILERS |
Metastases
Infection
Lymphoma
Eosinophilic granuloma
Rheumatoid arthritis
Sarcoma
Wrist & hand
Carpal Angle
= angle of 130 formed by tangents to proximal row of carpal bones
DECREASED CARPAL ANGLE (<124 )
Turner syndrome
Hurler syndrome
Morquio syndrome
Madelung deformity
INCREASED CARPAL ANGLE (>139 )
Down syndrome
Arthrogryposis
Bone dysplasia with epiphyseal involvement
P.20
Metacarpal Sign
= relative shortening of 4th + 5th metacarpals
tangential line along heads of 5th + 4th metacarpals intersects 3rd metacarpal Idiopathic
Pseudo- and pseudopseudohypoparathyroidism
Basal cell nevus syndrome
Multiple epiphyseal dysplasia
Beckwith-Wiedemann syndrome
Sickle cell anemia
Juvenile chronic arthritis
Gonadal dysgenesis: Turner syndrome, Klinefelter syndrome
Ectodermal dysplasia = Cornelia de Lange syndrome
Hereditary multiple exostoses
Peripheral dysostosis
Melorheostosis
mnemonic: Ping Pong Is Tough To Teach Pseudohypoparathyroidism
Pseudopseudohypoparathyroidism
Idiopathic
Trauma
Turner syndrome
Trisomy 13 18
Lucent Lesion in Finger
BENIGN TUMOR
Enchondroma
Epidermoid inclusion cyst
Giant cell tumor
Reparative granuloma
Sarcoidosis
Glomus tumor (rare)
others: aneurysmal bone cyst, brown tumor, hemophilic pseudotumor, solitary bone cyst, osteoblastoma
MALIGNANT TUMOR
Osteosarcoma
Fibrosarcoma
Metastasis from lung, breast, malignant melanoma
mnemonic: | GAMES PAGES |
Glomus tumor
Arthritis (gout, rheumatoid)
Metastasis (lung, breast)
Enchondroma
Simple cyst (inclusion)
Pancreatitis
Aneurysmal bone cyst
Giant cell tumor
Epidermoid
Sarcoid
Dactylitis
= expansion of bone with cystic changes
Tuberculous dactylitis (= spina ventosa)
Pyogenic / fungal infection
Syphilitic dactylitis
Sarcoidosis
Hemoglobinopathies
Hyperparathyroidism
Leukemia
Resorption of Terminal Tufts
TRAUMA
Amputation
Burns, electric injury
Frostbite
Vinyl chloride poisoning
NEUROPATHIC
Congenital indifference to pain
Syringomyelia
Myelomeningocele
Diabetes mellitus
Leprosy
COLLAGEN-VASCULAR DISEASE
Scleroderma
Dermatomyositis
Raynaud disease
METABOLIC
Hyperparathyroidism
INHERITED
Familial acroosteolysis
Pyknodysostosis
Progeria = Werner syndrome
Pachydermoperiostosis
OTHERS
Sarcoidosis
Psoriatic arthropathy
Epidermolysis bullosa
Acroosteolysis
Acroosteolysis: (a) acquired, (b) familial
Massive osteolysis
Essential osteolysis
Ainhum disease
Acquired Acroosteolysis
mnemonic: | PETER's DIAPER SPLASH |
Psoriasis, Porphyria
Ehlers-Danlos syndrome
Thrombangitis obliterans
Ergot therapy
Raynaud disease
Diabetes, Dermatomyositis, Dilantin therapy
Injury (thermal + electrical burns, frostbite)
Arteriosclerosis obliterans
PVC (polyvinylchloride) worker
Epidermolysis bullosa
Rheumatoid arthritis, Reiter syndrome
Scleroderma, Sarcoidosis
Progeria, Pyknodysostosis
Leprosy, Lesch-Nyhan syndrome
Absence of pain
Syringomyelia
Hyperparathyroidism
also in: yaws; Kaposi sarcoma; pachydermoperiostosis lytic destructive process involving distal + middle phalanges NO periosteal reaction epiphyses resist osteolysis until late
P.21
Acroosteosclerosis
= focal opaque areas + endosteal thickening
Incidental in middle-aged women
Rheumatoid arthritis
Sarcoidosis
Scleroderma
Systemic lupus erythematosus
Hodgkin disease
Hematologic disorders
Fingertip Calcifications
Scleroderma / CREST syndrome
Raynaud disease
Systemic lupus erythematosus
Dermatomyositis
Calcinosis circumscripta universalis
Hyperparathyroidism
Brachydactyly
= shortening / broadening of metacarpals phalanges
Idiopathic
Trauma
Osteomyelitis
Arthritis
Turner syndrome
Osteochondrodysplasia
Pseudohypoparathyroidism, Pseudopseudohypoparathyroidism
Mucopolysaccharidoses
Cornelia de Lange syndrome
Basal cell nevus syndrome
Hereditary multiple exostoses
Clinodactyly
= curvature of finger in mediolateral plane
Normal variant
Down syndrome
Multiple dysplasia
Trauma, arthritis, contractures
Polydactyly
Frequently associated with:
Carpenter syndrome
Ellis-van Creveld syndrome
Meckel-Gruber syndrome
Polysyndactyly syndrome
Short rib-polydactyly syndrome
Trisomy 13
Syndactyly
= osseous cutaneous fusion of digits
Apert syndrome
Carpenter syndrome
Down syndrome
Neurofibromatosis
Poland syndrome
Others
Shoulder
Shoulder Instability
= recurrent subluxation / dislocation of humeral head out of the glenoid socket during activities causing symptoms
Stabilizer: | inferior glenohumeral ligament-labrum complex (most important); anterior labrum-ligament complex |
Lesions after first anterior dislocation:
traumatic, unidrectional, Bankart, surgical (TUBS)
Age: <40 years fall on outstretched hand (FOOSH)
capsulolabral avulsion (Bankart lesion / its variant) anterior-inferior instability
atraumatic, multidirectional, bilateral inferior (AMBRI)
Age: >40 years tear of supraspinatus tendon (33%) fracture of greater tuberosity (33%) subscapularis avulsion from humerus (33%)
Hip
Snapping Hip Syndrome
INTRAARTICULAR
Osteocartilaginous bodies
EXTRAARTICULAR = tendon slippage
fascia lata / gluteus maximus over greater trochanter
iliopsoas tendon over iliopectineal eminence
long head of biceps femoris over ischial tuberosity
iliofemoral ligament over anterior portion of hip capsule
Increase in Teardrop Width
increase in distance between teardrop + femoral head Cause: hip joint effusion increase in mediolateral size of teardrop Cause: hip dysplasia, chronic hip joint effusion during skeletal maturation
Protrusio Acetabuli
= acetabular floor bulging into pelvis
medial wall of acetabulum projecting medially to ilioischial line by >3 mm (in males) / >6 mm (in females) crossing of medial + lateral components of pelvic teardrop (U-shaped radiodense area medial to hip joint with lateral aspect = acetabular articular surface
medial aspect = anteroinferior margin of quadrilateral surface of ilium)
UNILATERAL
Tuberculous arthritis
Trauma
Fibrous dysplasia
BILATERAL
Rheumatoid arthritis
Paget disease
Osteomalacia
P.22
mnemonic: | PROT |
Paget disease
Rheumatoid arthritis
Osteomalacia (HPT)
Trauma
Pain with Hip Prosthesis
Approximately 120,000 hip arthroplasties per year in USA
Heterotopic ossification
Trochanteric bursitis
Prosthetic fracture / periprosthetic fracture / cement fracture
Dislocation (due to capsular laxity / incorrect component placement)
Aseptic loosening
Incidence: 50% of prostheses after 10 years/utable. Cause:
mechanical wear + tear
small-particle disease (= inflammatory-immune reaction to methylmethacrylate / metallic fragments activates phagocytes with secretion of cytokines + proteolytic enzymes leading to osteolysis)
Rx: 30% require single-stage revision arthroplasty
Infection (= septic loosening)
Incidence: 1 9% Organisms: Staphylococcus epidermidis (31%), Staphylococcus aureus (20%), Streptococcus viridans (11%), Escherichia coli (11%), Enterococcus faecalis (8%), group B streptococcus (5%) Time of onset: 33% within 3 months, 33% within 1 year, 33% >1 year after surgery Rx: excisional arthroplasty + protracted course of antimicrobial therapy + revision arthroplasty
Plain film:
migration of prosthetic components compared to previous film: subsidence of prosthesis (up to 5 mm is normal for noncemented femoral component in first few months)
cement / prosthesis fracture motion of components on stress views / fluoroscopy widening of prosthesis-cement interface lucency at cement-bone interface >2 mm progressive widening of cement-bone lucency after 12 postoperative months focal lytic area (due to particulate debris with foreign body granuloma / abscess) extensive periostitis (in infection, but rare)
NUC (83% sensitive, 88% specific):
increased uptake of bone agent, Gallium-67, Indium-111 labeled leukocytes, complementary technetium-labeled sulfur colloid + combinations
Bone Scintigraphy:
normal = strong evidence against a prosthetic abnormality (= high NPV) diffuse intense uptake around femoral component (= generalized osteolysis associated with aseptic loosening or infection) focal uptake at distal tip of femoral component in >1 year old prosthesis = aseptic loosening
Sequential bone-gallium scintigraphy:
congruent spatial distribution of both tracers with gallium intensity less than bone tracer = no infection spatially incongruent / intensity of gallium exceeds that of bone agent = infection spatially congruent + similar intensity of both tracers = inconclusive
Combined labeled leukocyte marrow scintigraphy:
Accuracy: | >90% |
Concept: | Tc-99m sulfur colloid maps aberrantly located normal bone marrow as a point of reference for leukocyte tracer |
spatially congruent distribution of both radiotracers = no infection labeled leukocyte activity without corresponding sulfur colloid activity = infection
Arthrography:
irregularity of joint pseudocapsule filling of nonbursal spaces / sinus tracts / abscess cavities
Aspiration of fluid under fluoroscopy (12 93% sensitive, 83 92% specific for infection):
injection of contrast material to confirm intraarticular location
Evaluation of total hip arthroplasty
MEASUREMENTS
Reference line: | transischial tuberosity line (R) |
Leg length = vertical position of acetabular component = comparing level of greater / lesser tuberosity (T) with respect to line R
High placement: shorter leg, less effective muscles crossing the hip joint Low placement: longer leg, muscles stretched to point of spasm with risk of dislocation Vertical center of rotation
= distance from center of femoral head (C) to line R
Horizontal center of rotation
= distance from center of femoral head (C) to teardrop / other medial landmark
Lateral position: iliopsoas tendon crosses medial to femoral head center of rotation increasing risk of dislocation Lateral acetabular inclination = horizontal version
= angle of cup in reference to line R (40 10 desirable)
Less angulation: stable hip, limited abduction Greater angulation: risk of hip dislocation Varus / neutral / valgus stem position
Varus position: tip of stem rests against lateral endosteum, increased risk for loosening Valgus position: tip of stem rests against medial endosteum, not a significant problem P.23
Initial Evaluation of Total Hip Arthroplasty
Acetabular anteversion (15 10 desirable)
= lateral radiograph of groin
Retroversion: risk of hip dislocation Femoral neck anteversionworks synergistically with acetabular anteversion, true angle assessed by CT
Radiographic Findings in Total Hip Arthroplasty
NORMAL
irregular cement-bone interface = normal interdigitation of PMMA (polymethyl-methacrylate) with adjacent bone remodeling providing a mechanical interlock
PMMA is not a glue!
thin lucent line along cement-bone interface = 0.1 1.5-mm thin connective tissue membrane ( demarcation ) along cement-bone interface accompanied by thin line of bone sclerosis
ABNORMAL
wide lucent zone at cement-bone interface = 2-mm lucent line along bone-cement interface due to granulomatous membrane
Cause: component loosening reaction to particulate debris (eg, PMMA, polyethylene) lucent zone at metal-cement interface along proximal lateral aspect of femoral stem = suboptimal metal-cement contact at time of surgery / loosening
well-defined area of bone destruction(= histiocytic response, aggressive granulomatous disease) Cause: granulomatous reaction as response to particulate debris / infection / tumor asymmetric positioning of femoral head within acetabular component Cause: acetabular wear / dislocation of femoral head / acetabular disruption / liner displacement / deformity cement fracture Cause: loosening
Knee
Bone Contusion Pattern
edema of midportion of lateral femoral condyle Cause: pivot shift injury = valgus load + external rotation of tibia / external rotation of femurapplied to various states of flexion (noncontact injury) Predisposed: skier, football player Associated with injury of:
anterior cruciate lig. (midsubstance > femoral attachment > tibial attachment site)
posterior joint capsule + arcuate ligament
posterior horn of lateral / medial meniscus
medial collateral ligament
edema of posterior patellar surface Cause: dashboard injury = force upon anterior proximal tibia with knee in flexed position Associated with:
rupture of posterior cruciate lig. (midsubstance > femoral attachment > tibial attachment site)
tear of posterior joint capsule
fracture / osteochondral injury of patella
injury of hip
kissing bone contusion pattern = anterior aspect of tibial plateau + anterior aspect of femoral condyle
Cause: hyperextension injury = direct force upon anterior tibia while foot is planted / indirect force of forceful kicking motion Associated with:
injury to posterior / anterior cruciate lig.
meniscal injury
dislocation of knee
popliteal neurovascular injury
complete disruption of posterolateral complex
edema in lateral aspect of femoral condyle (secondary to direct blow)
small area of edema in medial femoral condyle (due to avulsive stress to medial collateral ligament) Predisposed: football player Cause: clip injury = pure valgus stress with knee in mild flexion Associated with injury of:
medial collateral ligament (at femoral attachment site
anterior cruciate ligament
medial meniscus
combination of all three = O'Donoghue triad
anterolateral aspect of lateral femoral condyle
inferomedial aspect of patella Predisposed: teenaged / young adult athletes with shallow trochlear groove Cause: lateral patellar dislocation = twisting motionwith knee in flexion + quadriceps contraction Associated with injury of:
medial retinaculum
medial patellofemoral ligament (near femoral attachment site) most important stabilizing structure)
medial patellotibial ligament
P.24
Double PCL sign on MRI
Bucket-handle tear of medial / lateral meniscus
Ligament of Humphrey
Torn ACL
Fracture fragments
Osteophyte
Loose body
Absent bow-tie sign
Bucket-handle tear of medial meniscus
Congenitally hypoplastic / ring-shaped meniscus
Small meniscus in child / petite adult
Partial meniscectomy
Arthritic degeneration
Unique Tibial Lesions
Fibrous dysplasia
Ossifying fibroma
Adamantinoma
Tibiotalar Slanting
= downward slanting of medial tibial plafond
Hemophilia
Still disease
Sickle cell disease
Epiphyseal dysplasia
Trauma
Foot
Abnormal Foot Positions
FOREFOOT
Varus = adduction
= axis of 1st metatarsal deviated medially relative to axis of talus
Valgus = abduction
= axis of 1st metatarsal deviated laterally relative to axis of talus
Inversion = supination
= inward turning of sole of foot
Eversion = pronation
= outward turning of sole of foot
HINDFOOT
talipes (talus, pes) = any deformity of the ankle and hindfoot
Equinus
= hindfoot abnormality with reversal of calcaneal pitch so that the heel cannot touch the ground
Calcaneal foot
= very high calcaneal pitch so that forefoot cannot touch the ground
Pes planus = flatfoot
= low calcaneal pitch + (usually) heel valgus + forefoot eversion
Pes cavus
= high calcaneal pitch (fixed high arch)
Clubfoot = Talipes Equinovarus
Common severe congenital deformity characterized by
equinus of heel (reversed calcaneal pitch)
heel varus (talocalcaneal angle of almost zero on AP view with both bones parallel to each other)
metatarsus adductus (axis of 1st metatarsal deviated medially relative to axis of talus)
Arthrogryposis multiplex congenita
Chondrodysplasia punctata
Neurofibromatosis
Spina bifida
Myelomeningocele
Rocker-bottom Foot = Vertical Talus
vertically oriented talus with increased talocalcaneal angle on lateral view dorsal navicular dislocation at talonavicular joint heel equinus rigid deformity
Associated with: Arthrogryposis multiplex congenita; spina bifida; trisomy 13 18 |
Talar Beak = Hypertrophied Talar Ridge
Talocalcaneal type of tarsal coalition
Diffuse idiopathic skeletal hyperostosis (DISH)
Acromegaly
Rheumatoid arthritis
Heel Pad Thickening
= heel pad thickening >25 mm (normal <21 mm)
mnemonic: | MAD COP |
Myxedema
Acromegaly
Dilantin therapy
Callus
Obesity
Peripheral edema
P.25
Soft-tissue Masses of Foot + Ankle
NONTUMORAL
synovial proliferations
Pigmented villonodular synovitis (PVNS)
Giant cell tumor (GCT) of tendon sheath
posttraumatic
Plantar fasciitis
inflammatory
uncertain origin
Ganglion cyst
Epidermoid cyst
Morton neuroma
Florid reactive periostitis
Rheumatoid nodules
BENIGN TUMORS
Plantar fibromatosis
Deep fibromatosis
Infantile digital fibromatosis
Hemangioma
Nerve sheath tumor
Lipoma, angiolipoma
Soft tissues
Categories of Soft-tissue Masses
NEOPLASTIC
Incidence: 300:100,000 annually; benign:malignant = 100:1 benign (most frequent)
Lipoma
Hemangioma
Desmoid tumor
Ganglion cyst
Pigmented villonodular synovitis
Neurofibroma (5%)
malignant (most frequent)
Frequency: 1% of all cancers in adults, increasing with age Malignant fibrous histiocytoma
Liposarcoma
INFLAMMATORY
TRAUMATIC
VASCULAR
Value of Conventional Radiographs
Identification of osseous abnormalities:callus related to fractures, osteocartilaginous mass, myositis ossificans
Identification of a primary bone lesion:osteomyelitis, Ewing sarcoma, osteosarcoma
Histologic Classification of Soft-tissue Lesions
FATTY
Lipoma
Angiolipoma
Liposarcoma
FIBROUS
Fibroma
Nodular fasciitis
Aggressive fibromatosis / desmoid
Fibrosarcoma
MUSCLE
Rhabdomyoma
Leiomyoma
Rhabdomyosarcoma
Leiomyosarcoma
VASCULAR
Hemangioma
Hemangiopericytoma
Hemangiosarcoma
LYMPH
Lymphangioma
Lymphangiosarcoma
Lymphadenopathy in lymphoma / metastasis
SYNOVIAL
Nodular synovitis
Pigmented villonodular synovitis
Synovial sarcoma
NEURAL
Neurofibroma
Neurilemoma
Ganglioneuroma
Malignant neuroblastoma
Neurofibrosarcoma
CARTILAGE AND BONE
Myositis ossificans
Extraskeletal osteoma
Extraskeletal chondroma
Extraskeletal chondrosarcoma
Extraskeletal osteosarcoma
Fat-containing Soft-tissue Masses
BENIGN LIPOMATOUS TUMORS
Lipoma
Intra- / intermuscular lipoma
Synovial lipoma
Lipoma arborescens = diffuse synovial lipoma
Neural fibrolipoma = fibrolipomatous tumor of nerve
Macrodystrophia lipomatosa
LIPOMA VARIANTS
Lipoblastoma (only in infancy + early childhood)
Lipomatosis = diffuse overgrowth of mature adipose tissue infiltrating through the soft tissues of affected extremity / trunk
Hibernoma = rare benign tumor of brown fat; often in peri- / interscapular region, axilla, thigh, chest wall
marked hypervascularity
MALIGNANT LIPOMATOUS TUMOR
Liposarcoma
OTHER FAT-CONTAINING TUMORS
Hemangioma
Elastofibroma
LESIONS MIMICKING FAT-CONTAINING TUMORS
Myxoid tumors: intramuscular myxoma, extraskeletal myxoid chondrosarcoma, myxoid malignant fibrous histiocytoma
Neural tumors: neurofibroma, neurilemoma, malignant schwannoma
73% have tissue attenuation less than muscle
Hemorrhage
P.26
Extraskeletal Osseous + Cartilaginous Tumors
OSSEOUS SOFT-TISSUE TUMORS
cloudlike cumulus type of calcification
Myositis ossificans
Fibrodysplasia ossificans progressiva
Soft-tissue osteoma
Extraskeletal osteosarcoma
Myositis ossificans variants
Panniculitis ossificans
Fasciitis ossificans
Fibroosseous pseudotumor of digits
CARTILAGINOUS SOFT-TISSUE TUMORS
arcs and rings, spicules and floccules of calcification
Synovial osteochondromatosis
Soft-tissue chondroma
Extraskeletal chondrosarcoma
DDx:
Synovial sarcoma
Benign mesenchymoma
= lipoma with chondroid / osseous metaplasia
Malignant mesenchymoma
= 2 or more unrelated sarcomatous components
Calcified / ossified tophus of gout
Ossified soft-tissue masses of melorheostosis
Tumoral calcinosis
Pilomatricoma = calcifying epithelioma of Malherbe
lesion arises from hair matrix cells with slow growth confined to the subcutaneous tissue of the face, neck, upper extremities
central sandlike calcifications (84%) peripheral ossification (20%)
Soft-tissue Calcification
Metastatic / Metabolic Calcification
= deposit of calcium salts in previously normal tissue
as a result of elevation of Ca P product above 60 70
with normal Ca P product after renal transplant
Location: | lung (alveolar septa, bronchial wall, vessel wall), kidney, gastric mucosa, heart, peripheral vessels |
Cause:
Skeletal deossification
1 HPT
Ectopic HPT production (lung / kidney tumor)
Renal osteodystrophy + 2 HPT
Hypoparathyroidism
Prolonged immobilization
Massive bone destruction
Widespread bone metastases
Plasma cell myeloma
Leukemia
Hypercalcemia
Primary hyperparathyroidism
Hypervitaminosis D
Milk-alkali syndrome
Sarcoidosis
Hydroxyapatite deposition disease
IV administration of calcium salts
Idiopathic hypercalcemia
Hyperuricemia
Tophaceous gout
Dystrophic Calcification
= in presence of normal serum Ca + P levels secondary to local electrolyte / enzyme alterations in areas of tissue injury / inflammation
Cause:
Metabolic disorder without hypercalcemia
Renal osteodystrophy with 2 HPT
Hypoparathyroidism
Pseudohypoparathyroidism
Pseudopseudohypoparathyroidism
Gout
Pseudogout = chondrocalcinosis
Ochronosis = alkaptonuria
Diabetes mellitus
Connective tissue disorder
Scleroderma = progressive systemic sclerosis
Dermato- and polymyositis
Systemic lupus erythematosus
Mixed connective tissue disorders
Trauma
Neuropathic calcifications
Frostbite
Myositis ossificans progressiva
Infestation
Cysticercosis
Dracunculosis (guinea worm)
Loiasis
Bancroft filariasis
Hydatid disease
Leprosy
Vascular disease
Atherosclerosis
Media sclerosis (M nckeberg)
Venous calcifications
Tissue infarction (eg, myocardial infarction)
Miscellaneous
Ehlers-Danlos syndrome
Pseudoxanthoma elasticum
Werner syndrome = progeria
Calcinosis (circumscripta, universalis, tumoral calcinosis)
Neoplastic disease
Synovial sarcoma
Osteosarcoma
Chondrosarcoma
Necrotic tumor
Degenerative disease
Calcium pyrophosphate deposition disease
Calcific tendonitis (in 3% of adults)
Location: shoulder > hip > elbow > wrist > knee
Calcific bursitis
Metaplasia
Synovial osteochondromatosis
Generalized Calcinosis
Collagen vascular disorders
Scleroderma
Dermatomyositis
P.27
Idiopathic calcinosis universalis
Idiopathic Calcification
Tumoral calcinosis
normal calcium + elevated phosphate levels
Interstitial Calcinosis
Calcinosis Circumscripta
firm white commonly ulcerating dermal papules / plaques / subcutaneous nodules extruding a chalky white material of hydroxyapatite
Acrosclerosis: granular deposits around joints of fingers + toes, fingertips
Scleroderma + CREST syndrome: acrosclerosis + absorption of ends of distal phalanges
Dermatomyositis: extensive subcutaneous deposits
Varicosities: particularly in calf
1 Hyperparathyroidism: infrequently periarticular calcinosis
Renal osteodystrophy with 2 hyperparathyroidism: extensive vascular deposits even in young individuals
Hypoparathyroidism: occasionally around joints; symmetrical in basal ganglia
Vitamin D intoxication: periarticular in rheumatoid arthritis (puttylike); calcium deposit in tophi
Calcinosis Universalis
Progressive disease of unknown origin
Age: children + young adults Associated with: poly- and dermatomyositis plaque- / sheetlike calcium deposits in skin + subcutis; sometimes in tendons + muscles + fascia NO true bone formation
Soft-tissue Ossification
= formation of trabecular bone
Myositis ossificans progressiva / circumscripta
Paraosteoarthropathy
Soft-tissue osteosarcoma
Parosteal osteosarcoma
Posttraumatic periostitis = periosteoma
Surgical scar
Severely burned patient
Connective Tissue Disease
= CTD = [COLLAGEN VASCULAR DISEASE]
= group of disorders that share a number of clinical + laboratory features
Features:
relatively specific: arthritis, myositis, Raynaud phenomenon with digital ulceration, tethered skin in extremities + trunk, malar rash sparing nasolabial folds, morning stiffness
relatively nonspecific: polyarthralgias (most common initial symptom), myalgias, mottling of extremities, muscle weakness + tenderness
Laboratory findings:
relatively specific: ANA in peripheral rim / nucleolar pattern, anti-DNA, elevated muscle enzyme
relatively nonspecific: ANA in homogeneous pattern, anti-single-stranded DNA, positive rheumatoid factor
Types and most distinctive features:
Rheumatoid arthritispositive rheumatoid factor, prominent morning stiffness, symmetric erosive arthritis
Systemic lupus erythematosusmalar rash, photosensitivity, serositis, renal disorders with hemolytic anemia, leukopenia, lymphopenia, thrombocytopenia, positive ANA
Sj gren syndromedry eyes + mouth, abnormal Schirmer test
SclerodermaRaynaud phenomenon, skin thickening of distal extremities proceeding to include proximal extremities + chest + abdomen, positive ANA in a nucleolar pattern
Polymyositis, dermatomyositisheliotrope rash over eyes, proximal muscle weakness, elevated muscle enzymes, inflammation at muscle biopsy
Mixed Connective Tissue Disease
= disorder that shares distinctive features of 2 different connective tissue diseases in same patient (eg, overlapping features of SLE, PSS, polymyositis)
pulmonary hypertension (due to interstitial pulmonary fibrosis / intimal proliferation of pulmonary arterioles)
Muscle
MR signal intensity of normal muscle:
higher than water + lower than fat on T1WI much lower than water + fat on T2WI
Intramuscular Mass
NEOPLASM
INFECTION / INFLAMMATION
Intramuscular abscess
Focal myositis = benign inflammatory pseudotumor
Necrotizing fasciitis
Sarcoidosis
nodules with central star-shaped area of fibrosis surrounded by granuloma
MYONECROSIS
Sickle cell crisis
Poorly controlled diabetes
Compartment syndrome
Crush injury
Severe ischemia
Intraarterial chemotherapy
Rhabdomyolysis = severe muscle injury with loss of integrity of muscle cell membranes
Cause: trauma, severe exercise, ischemia, burn, toxin, IV heparin therapy, autoimmune inflammation Cx: renal damage from myoglobulinemia, tetany, compartment syndrome
TRAUMA
Intramuscular hematoma (eg, severe muscle strain, laceration, contusion, spontaneous)
Myositis ossificans traumatica
P.28
Muscle Edema
INFLAMMATION
Dermatomyositis
Polymyositis
Radiation therapy: straight sharp margins, involves muscle + subcutaneous fat
Early stage of myositis ossificans
CELLULAR INFILTRATE
Lymphoma
INFECTION
Bacterial / infectious myositis
direct extension from adjacent infection (eg, osteomyelitis, subcutaneous abscess)
hematogenous
Inclusion body myositis (probably due to para-myxovirus infection) resembling polymyositis
RHABDOMYOLYSIS
Sport / electric injury
Diabetic muscular infarction
Focal nodular myositis
Metabolic myopathy: eg, phosphofructokinase deficiency, hypokalemia, alcohol overdose
Viral myositis
TRAUMA
Subacute muscle denervation
Time of onset: 2 4 weeks after denervation Mechanism:
spinal cord injury, poliomyelitis, peripheral nerve injury / compression (ganglion cyst, bone spur), Graves disease, neuritis
Muscle contusion (from direct blow)
Muscle strain (= injury at musculotendinous junction from overly forceful muscle contraction)
Predilection for: hamstring, gastrocnemius m., biceps brachii m.) Delayed-onset muscle soreness
= overuse injury becoming symptomatic hours / days after overuse episode)
Compartment syndrome
= increased pressure within indistensible space of confining fascia leading to venous occlusion, muscle + nerve ischemia, arterial occlusion, tissue necrosis
Cause: trauma, burns, heavy exercise, extrinsic pressure, intramuscular hemorrhage severe pain
dysfunction of sensory + motor nerves passing through affected compartment
Sickle cell crisis
Fatty Infiltration of Muscle
Chronic stage of muscle denervation (eg, poliomyelitis, stroke, peripheral nerve injury)
Chronic disuse (eg, chronic tendon tear, severe osteoarthritis)
Late stage of severe muscle injury
Long-term high-dose corticosteroid medication affecting truncal muscles
Fixation devices
Internal Fixation Devices
Screws
Cortical screw = shallow finely threaded over entire length, blunt tip
Use: fixation of plates Cancellous screw = wide thread diameter with varying length of smooth shank between head + threads
Use: compression across fracture site Malleolar screw = partially threaded
Interference screw = short, fully threaded, cancellous thread pattern, self-tapping tip, recessed head
Use: within tunnel holding bone graft of ACL and PCL reconstruction Cannulated screw = hollow screw inserted over guide pin
Use: fracture of femoral neck Herbert screw = cannulated screw threaded on both ends with different pitches, no screw head
Use: scaphoid fracture Dynamic hip screw = screw free to slide within barrel of side plate allowing impaction of fracture during healing without perforation of subarticular cortex
Use: subcapital, intertrochanteric, subtrochanteric fracture
Washer
Flat washer = increase surface area over which force is distributed
Serrated washer = spiked edges used for affixing avulsed ligaments
Plates
compression plate
Use: compression of stable fractures neutralization plate = protects fracture from bending, rotation + axial-loading forces
buttress plate = support of unstable fractures in compression / axial loading
Straight plate
straight plate with round holes
dynamic compression plate = oval holes
tubular plate = thin pliable plate with concave inner surface
reconstruction plate = thin pliable plate to allow bending, twisting, contouring
Special plates
T-shaped, L-shaped, Y-shaped, cloverleaf, spoon, cobra, condylar blade plate, dynamic compression screw system
Staples
Fixation = bone = epiphyseal = fracture staples with smooth / barbed surface Coventry = stepped osteotomy staple
stone = table staple
Wires
K wire = unthreaded segments of extruded wire of variable thickness
Use: temporary fixation Cerclage wiring = wire placed around bone
P.29
No Caption Available.
P.30
Use: fixation of comminuted patellar fracture, holding bone grafts in position Tension band wiring = figure-of-eight wire placed on tension side of bone
Use: olecranon / patellar fractures
External Fixation Devices
= smooth / threaded pins / wires attached to an external frame
unilateral pin = enters bone only from one side
Steinmann pin = large-caliber wire with pointed tip
Rush pin = smooth intramedullary pin
Schanz screw = pin threaded at one end to engage cortex, smooth at other end to connect to external fixation device
Knowles pin (for femoral neck fracture)
transfixing pin = passes through extremity supported by external fixation device on both ends
Intramedullary Fixation Devices
Use: | diaphyseal long bone fractures |
(a) nail = driven into bone without reaming
(b) rod = solid / hollow device with blunted tip driven into reamed channel (reaming disrupts blood supply and may decrease the rate of fracture healing)
(c) interlocking nail = accessory pins / screws / deployable fins placed to prevent rotation
1. Rush pin = beveled end + hooked end
2. Ender nail = oval in cross section
3. Sampson rod = slightly curved rigid rod with fluted surface
4. K ntscher nail = cloverleaf in cross section with rounded tip
P.31
Anatomy and Metabolism of Bone
Bone minerals
Calcium
99% in bone
serum calcium
protein-bound fraction (albumin)
ionic (pH-dependent) 3% as calcium citrate / phosphate in serum
Absorption: | facilitated by vitamin D |
Excretion: | related to dietary intake; >500 mg/24 hours = hypercalciuria |
Phosphorus
Absorption: | requires sodium; decreased by aluminum hydroxide gel in gut |
Excretion: | increased by estrogen, parathormone decreased by vitamin D, growth hormone, glucocorticoids |
Bone marrow
Red marrow
= hematopoietically active with a rich + extensive vascular supply, composed of erythrocyte + leukocyte + platelet precursors
in adolescence: 40% fat, 40% water, 20% protein at age 70: 60% fat, 30% water, 10% protein Yellow / fatty marrow
with a sparse vascular network; composed of 80% fat, 15% water, 5% protein
Distribution changes throughout life with conversion from red to fatty marrow @ birth: marrow contains primarily hematopoietically active cells @ 1 year: phalanges of feet @ puberty: diaphysis of long bones @ 1st 2 decades: conversion begins in appendicular skeleton progressing to the axial skeleton; conversion in long bones begins in diaphysis > distal metaphysis > proximal metaphysis @ 3rd decade: residual red marrow remains in skull, spine, sternum, flat bones, proximal ends of humerus + femur; acetabulum superiorly + medially > ilium > around sacroiliac joints
Anatomic sites for MRI marrow screening:
spine (SAG images)
pelvis + femora (COR images)
Parathormone Function
PTH Action Net Effect Principal: (1) phosphate diuresis (1) Serum: increase in Ca (2) resorption of Ca + P from bone decrease in P Secondary: (3) resorption of Ca from gut (2) Urine: increase in Ca (4) reabsorption of Ca from renal tubule increase in P Differences in signal intensity are maximized on T1WI but diminished on T2WI red marrow: iso- / slightly hyperintense compared with muscle on T1WI + T2WI (longer T1 relaxation time) hypointense compared with fatty marrow (shorter T2 relaxation time)
yellow marrow: isointense compared with subcutaneous fat on T1WI (relatively short T1 relaxation time compared with water) iso- / hypointense compared with subcutaneous fat on T2WI hyperintense compared with muscle on T2WI (long T2 relaxation time compared with water)
Hormones
Parathormone
Major stimulus: | low levels of serum calcium ions (action requires vitamin D presence) |
Target organs:
(a) BONE: | increase in osteocytic + osteoclastic activity mobilizes calcium + phosphate = bone resorption |
(b) KIDNEY: | (1) increase in tubular reabsorption of Ca2+ (2) decrease in tubular reabsorption of phosphate (+ amino acids) = phosphate diuresis |
(c) GUT: | increased absorption of calcium + phosphorus |
Major function:
increase of serum calcium levels
increase in serum alkaline phosphatase (50%)
Vitamin D Metabolism
required for
adequate calcium absorption from gut
synthesis of calcium-binding protein in intestinal mucosa
parathormone effects (stimulation of osteoclastic + osteocytic resorption of bone)
Biochemistry:
inactive form of vitamin D3 present through diet / exposure to sunlight (photoconversion of 7-dehydrocholesterol in skin to cholecalciferol); vitamin D3 is converted into 25-OH-vitamin D3 by liver and then converted into 1,25-OH vitamin D3 (biologically most active form = hormone) by kidney
P.32
Stimulus for conversion: (1) hypophosphatemia (2) PTH elevation
Action:
(a) BOWEL: | (1) increased absorption of calcium from bowel (2) increased absorption of phosphate from distal small bowel |
(b) BONE: | (1) proper mineralization of osteoid (2) mobilization of calcium + phosphate (potentiates parathormone action) |
(c) KIDNEY: | (1) increased absorption of calcium from renal tubule (2) increased absorption of phosphate from renal tubule |
(d) CELL: | binds to receptor on nucleus which leads to activation of genes involved in calcium homeostasis |
Calcitonin
secreted by parafollicular cells of thyroid
Major stimulus: | increase in serum calcium |
Target organs:
(a) BONE: | (1) inhibits parathormone-induced osteoclasis by reducing number of osteoclasts (2) enhances deposition of calcium phosphate; responsible for sclerosis in renal osteodystrophy |
(b) KIDNEY: | inhibits phosphate reabsorption in renal tubule |
(c) GUT: | increases excretion of sodium + water into gut |
Major function: | decreases serum calcium + phosphate |
Physis = Growth Plate
Four distinct zones of cartilage in longitudinal layers
Germinal zone = small cells
adjacent to epiphyseal ossification center
Zone of proliferation = flattened cells
arranged in columns
Zone of hypertrophy = swollen vacuolated cells
zone of maturation
zone of degeneration
zone of provisional calcification
Zone of primary and secondary spongiosa
Normal shoulder joint anatomy
Glenoid Labrum
= 4-mm wide fibrocartilaginous ring with considerable variation in shape attached to glenoid rim
variations in attachment above epiphyseal line (= junction of upper + middle thirds of glenoid body fossa) labrum continuous with glenoid articular cartilage inferior to epiphyseal line triangular / rounded shape on cross-sectional image blends superiorly with biceps tendon
Superior Sublabral Sulcus / Recess
= variations in depth of sulcus between glenoid rim + labrum
Types of Attachment of the Biceps-Labral Complex |
Location: | 12 o'clock position at the site of biceps tendon attachment (in sagittal plane) |
Types of attachment of biceps-labral complex (BLC):
BLC firmly adherent to superior pole of glenoid without a sulcus / sublabral foramen
small sulcus = BLC attached several mm medially; hyaline cartilage beneath labrum; may be continuous with sublabral foramen which is anterior to BLC
deep probe-patent sulcus = meniscoid labrum with large sulcus between labrum and hyaline cartilage
may be continuous with sublabral foramen best visualized on coronal CT / MR DDx: type II SLAP lesion
Biceps Tendon
= long head of biceps muscle
attached to anterosuperior aspect of glenoid rim with fibers to anterosuperior labrum (biceps-labral complex)
posterosuperior labrum (biceps-labral complex)
supraglenoid tubercle
base of coracoid process
exits joint through intertubercular groove secured to intertubercular groove by transverse lig.
Glenohumeral Ligaments
= thickened bands of joint capsule functioning as shoulder stabilizers
Superior Glenohumeral Ligament
= most consistently identified
arises from upper pole of glenoid cavity and base of coracoid process attaches to middle glenohumeral ligament + anterosuperior labrum + biceps tendon inserts just superior to lesser tuberosity in region of bicipital groove courses in plane perpendicular to middle glenohumeral ligament + parallel to coracoid process best visualized on transverse CT / MR
Middle Glenohumeral Ligament (MGL)
= varies most in size + attachment; may be absent
ligament stretched when arm externally rotated
courses obliquely from superomedial to inferolateral attaches medially on scapular neck / superior portion of anterior glenoid rim attaches to anterior aspect of anatomic neck of humerus medial to lesser tuberosity may be thick + cordlike best visualized on sagittal / transverse CT / MR Normal Anatomy of Right Shoulder En Face (arrow in sublabral foramen)
P.33
Inferior Glenohumeral Ligament (IGL)
= important stabilizer of anterior shoulder joint, ie, it tightens during abduction + external rotation + prevents glenohumeral dislocation at the end range of motion
ligament + labrum function as single unit = glenohumeral labral-ligamentous complex
attaches to inferior 2/3 of the circumference of the entire labrum over a variable distance attaches to humerus laterally
Parts:
Anterior band of IGL = thickened anterior-superior extent of ligament
Axillary pouch
Posterior band of IGL (usually thinner)
Normal Anatomic Variants of Shoulder
Sublabral Foramen = Sublabral Hole
= sublabral hole between labrum + glenoid
Incidence: | 11% of individuals |
Location: | 2 o'clock position anterior to biceps tendon attachment |
DDx: | labral tear |
Buford Complex
= cordlike thickening of middle glenohumeral ligament directly attaching to anterosuperior glenoid + absence of anterosuperior labrum
Incidence: 1.5% of individuals Location: 2 o'clock position anterior to biceps tendon attachment course of middle glenohumeral ligament can be followed on serial images from origin to insertion may coexist with sublabral recess DDx: displaced anterosuperior labral fragment Buford Complex
Rotator Cuff (dorsal aspect)
Coracoacromial Arch (lateral aspect)
P.34
Foramen of Weitbrecht
= opening between SGL and MGL
Foramen of Rouviere
= opening between MGL and IGL
Rotator cuff muscles
mnemonic: | SITS |
Supraspinatus
Infraspinatus
Teres minor
Subscapularis
Occurrence of bone centers at elbow
mnemonic: | CRITOE |
Capitellum | 1 year | (3 6 months) |
Radial head | 4 years | (3 6 years) |
Internal humeral epicondyle | 7 years | (5 7 years, last to fuse) |
Trochlea | 10 years | (9 10 years) |
Olecranon | 10 years | (6 10 years) |
External humeral epicondyle | 11 years | (9 13 years) |
mnemonic: | Nelson's X: 1, 7, 10, 11 years |
Carpal bones
mnemonic: | Some Lovers Try Positions That They Can't Handle |
proximal row | distal row |
---|---|
Scaphoid | Trapezium |
Lunate | Trapezoid |
Triquetrum | Capitate |
Pisiform | Hamate |
Remember that trapezium comes before trapezoid in the dictionary as well!
Ulnar Variance
= HULTEN VARIANCE = RADIOULNAR INDEX
= relative lengths of distal articular surfaces of radius and ulna
Definition:
neutral = both surfaces at same level = equal length of ulna + radius
positive = ulnar surface distal to radial surface = long ulna
negative = ulnar surface proximal to radial surface = short ulna
Occurrence of Bone Centers (numbers in years)
Carpal Tunnel (radiograph)
Wrist Cross Section of Distal Radioulnar Joint with the 6 Extensor Compartments (dorsal aspect)
Carpal Bones and Ligaments (volar aspect)
P.35
Central Segments of Scapholunate and Lunotriquetral Ligaments (coronal)
Palmar and Dorsal Segments of Scapholunate and Lunotriquetral Ligaments (transverse)
Effect of wrist position:
increase of ulnar variance
maximum forearm pronation
firm grip
decrease of ulnar variance
maximum forearm supination
cessation of grip
Radiographic standard view of unloaded wrist:
posteroanterior, neutral forearm rotation, elbow flexed 90 , shoulder abducted 90
Lower extremity
Pes Anserinus
= [pes, Latin = foot; anser, Latin = goose]
= tendinous configuration of 3 flexors + medial rotators of knee joint attaching inferomedially to tibial tuberosity
mnemonic: Say GraceSe before eating goose Sartorius tendon (anterior)
Gracilis tendon (middle)
Semitendinosus tendon (posterior)
Iliotibial Tract
= strong stabilizing band of deep fascia composed of the fusion of aponeurotic coverings of:
Tensor fascia lata
Gluteus maximus m.
Gluteus medius m.
Insertion:
supracondylar tubercle of lateral femoral condyle
lateral tubercle of tibia = Gerdy tubercle (main site)
patella + patellar ligament
Hamstrings
medial hamstring
Semimembranosus m.
Semitendinosus m.
Function: flexion + medial rotation of knee joint
lateral hamstring
= long + short head of biceps femoris m.
Function: flexion + lateral rotation of knee joint
Cruciate Ligaments
Anterior Cruciate Ligament (ACL)
Function: | limits anterior tibial translation |
Origin: | inner face of lateral femoral condyle |
Insertion: | noncartilaginous region of anterior aspect of intercondylar eminence of tibia |
Anatomy: | several distinct bundles of fibers (1) large posterior bulk = spiraling together at femoral origin (2) small anteromedial bundle diverging at tibial insertion |
thin solid taut dark band (sagittal MR with knee in extension) almost parallel to intercondylar roof (= Blumensaat line): with knee extension posterolateral band taut with increasing flexion: anteromedial band becomes more taut + posterolateral band more lax
thin hypointense band parallel to inner aspect of lateral femoral condyle + fanlike configuration toward tibial spine (coronal MR) thin ovoid hypointense band proximally, elliptical configuration distally with higher intensity (axial MR) greater signal intensity than posterior cruciate ligament (due to anatomy)
Posterior Cruciate Ligament (PCL)
Function: | limits posterior tibial translation |
Origin: | in a depression posterior to intercondylar region of tibia below joint surface |
Insertion: | most distal + anterior aspect of inner face of medial femoral condyle |
thick dark band slightly posteriorly convex (arclike course on sagittal MR with knee in extension) medial to ACL (coronal MR)
Collateral Ligaments of Knee Joint
Medial (Tibial) Collateral Ligament
Origin: | just distal to adductor tubercle of femur |
Insertion: | anteromedial face of tibia distal to level of tibial tubercle about 5 cm below joint line |
P.36
Muscle Attachments of Shoulder
Name of Muscle | Origin | Insertion |
---|---|---|
Deltoid | lateral third of clavicle | deltoid tuberosity of humerus |
lateral border of acromion | deltoid tuberosity of humerus | |
lower part of spinous process of scapula | deltoid tuberosity of humerus | |
Subscapularis | medial 2/3 of costal surface of scapula | superior aspect of lesser tubercle of humerus |
Pectoralis major | ||
clavicular portion | medial half of clavicle | crest of greater tubercle of humerus |
sternocostal portion | manubrium + corpus of sternum | crest of greater tubercle of humerus |
abdominal portion | anterior sheath of rectus abdominis | crest of greater tubercle of humerus |
Pectoralis minor | 2nd / 3rd 5th ribs | superomedial aspect of coracoid process |
Biceps brachii | ||
long head | supraglenoid tubercle of scapula | tuberosity of radius |
short head | tip of coracoid process | tuberosity of radius |
Coracobrachialis | tip of coracoid process | medial surface of middle third of humerus |
Supraspinatus | supraspinatus fossa of scapula | greater tubercle of humerus, highest facet |
Infraspinatus | infraspinatus fossa of scapula | greater tubercle of humerus, middle facet |
Teres minor | upper 2/3 of lateral border of scapula | greater tubercle of humerus, lower facet |
Teres major | dorsum of inferior angle of scapula | inferior crest of lesser tubercle of humerus |
Hip Flexors |
Muscle Attachments of Thigh
Name of Muscle | Origin | Insertion |
---|---|---|
Gracilis | inferior pubic ramus | pes anserinus |
Semimembranosus | ischial tuberosity | medial tibial condyle |
Semitendinosus | ischial tuberosity | pes anserinus |
Biceps femoris | ||
long head | ischial tuberosity | fibular head |
short head | lateral linea aspera | fibular head |
Adductor | ||
longus | superior pubic ramus | medial linea aspera |
magnus | inferior pubic ramus | medial linea aspera |
Sartorius | anterior superior iliac spine | pes anserinus |
Quadriceps | ||
rectus | anterior inferior iliac spine | patellar tendon |
vastus lateralis | greater trochanter | patellar tendon |
vastus medialis | medial intertrochanteric line | patellar tendon |
Iliopsoas | ||
iliacus | ilium | lesser trochanter |
psoas | lumbar spine | lesser trochanter |
Tensor fasciae latae | anterior superior iliac spine | anterolateral tibia |
P.37
Cross Section through L4-5 |
Cross Section through S1-2 |
Cross Section through Acetabular Roof |
Cross Section through L5-S1 |
Cross Section through S4 |
Cross Section through Greater Trochanter |
P.38
Cross Section through Obturator Foramen |
Cross Section through Mid Thigh |
Fat Pads of the Right Hip in Perfect AP Position |
Cross Section through Minor Trochanter |
Cross Section through Mid Thigh |
Bony Landmarks of the Right Hip in Perfect AP Position |
P.39
deep portion:
meniscofemoral ligament
meniscotibial ligaments
superficial portion
vertical band from femoral epicondyle to pes anserinus
posterior oblique ligament = posterior oblique band from femoral epicondyle to semimembranosus tendon
Lateral (Fibular) Collateral Ligament
Origin: | lateral aspect of lateral femoral condyle |
Insertion: | styloid process of fibular head |
bicipital tendon + iliotibial band join lateral collateral ligament
Posterior Ankle Tendons
Achilles Tendon
Size: | 7 mm in AP thickness (largest tendon of the body) |
Origin: | gastrocnemius + soleus muscle |
surrounded by loose paratenon without tendon sheath
Plantaris Tendon
Insertion: | Achilles tendon. calcaneus, plantar fascia |
Medial Flexor Tendons
Posterior Tibialis Tendon
Size: | twice the size of flexor digitorum longus tendon |
Course: | beneath medial malleolus (used as pulley) |
Insertion: | navicular, all cuneiforms, base of first four metatarsals, os naviculare |
Flexor Digitorum Longus
Flexor Hallucis Longus
Course: | groove beneath posterior process of talus, beneath sustentaculum tali |
Insertion: | base of distal phalanx of hallux |
Cross Section through Distal Right Leg mnemonic for medial tendons: Tom, Dick and Harry from medial to lateral |
Tibialis posterior
Digitorum longus (flexor)
Hallucis longus (flexor)
P.40
Plantar Compartments of the Midfoot |
Plantar Compartments of the Forefoot |
Medial compartment | = | bordered by medial septum (extending from plantar aponeurosis to navicular bone, medial cuneiform bone, and lateral border of plantar surface of 1st metatarsal bone); contains abductor hallucis m. + flexor hallucis brevis m. + flexor hallucis longus tendon |
Lateral compartment | = | bordered by lateral septum (extending from plantar aponeurosis to medial surface of 5th metatarsal bone); contains abductor m. + short flexor m. + opponens m. of 5th toe |
Central compartment | = | bordered by medial + lateral septa; communicates directly with posterior compartment of calf; subdivided by horizontal septa: adductor hallucis m. separated from quadratus plantae m.; contains flexor digitorum brevis m. + flexor digitorum longus tendon + quadratus plantae m. + lumbricales mm. + adductor hallucis m. |
Deep subcompartment | = | bordered by transverse fascia of forefoot; separated from quadratus plantae m.; contains adductor hallucis m. |
P.41
Accessory Ossicles of the Foot |
Os talotibiale
Os supratalare
Os supranaviculare
Os infranaviculare
Os intercuneiforme
Os cuneometatarsale II dorsale
Os intermetatarsale
Secondary cuboid
Calcaneus secundarius
Os tibiale externum
Trigonum
Os accessorium supracalcaneum
Os subcalcis
Os peroneum
Os vesalianum
Talus accessorius
Os cuneonaviculare mediale
Sesamum tibiale anterius
Os cuneometatarsale I plantare
Cuboides secundarium
Os trochleare calcanei
Sesamoid talus - int. malleolus
Os subtibiale
Os sustentaculi
Os retinaculi
Os subfibulare
Talus secundarius
Calcaneal Pitch = Calcaneal Inclination Angle = determines longitudinal arch of foot; angle between line drawn along the inferior border of calcaneus connecting the anterior and posterior prominences + line representing the horizontal surface |
Boehler Angle = angle between first line drawn from posterosuperior prominence of calcaneus anteriorly to sustentaculum tali + second line drawn from anterosuperior prominence posteriorly to sustentaculum tali; measures integrity of calcaneus |
Talocalcaneal Angle on LAT View = angle between lines drawn through mid-transverse planes of talus + calcaneus; the midtalar line parallels the longitudinal axis of the first metatarsal |
Intermetatarsal Angle = amount that 1st + 2nd metatarsals diverge from each other |
Heel Valgus cannot be measured directly on radiographs but inferred from the talocalcaneal angle and estimated on coronal CT sections |
Talocalcaneal Angle on AP View = KITE ANGLE = the midtalar and midcalcaneal lines parallel the 1st + 4th metatarsals; angle is greater in infants |
Angle of Metatarsal Heads = obtuse angle formed by lines tangential to metatarsal heads |
P.42
Bone and Soft-Tissue Disorders
Achondrogenesis
= autosomal recessive lethal chondrodystrophy characterized by extreme micromelia, short trunk, large cranium
TRIAD: | (1) severe short-limb dwarfism (2) lack of vertebral calcification (3) large head with normal / decreased calvarial ossification |
Birth prevalence: | 2.3:100,000 |
Path: | disorganization of cartilage |
TYPE I = Parenti-Fraccaro disease
= defective enchondral + membranous ossification
complete lack of ossification of calvarium + spine + pelvis absent sacrum + pubic bone extremely short long bones without bowing, especially femur, radius, ulna thin ribs with multiple fractures (frequent)
TYPE II = Langer-Saldino disease
= defective enchondral ossification only
good ossification of skull vault nonossification of lower lumbar vertebrae + sacrum short + stubby horizontal ribs without fractures
often subcutaneous edema
irregular flared metaphyses (esp. humerus) short trunk with narrow chest + protruding abdomen redundant soft tissues polyhydramnios (common) increase in HC:AC ratio
Prognosis: | lethal often in utero / within few hours or days after birth (respiratory failure) |
DDx: | often confused with thanatophoric dwarfism |
Achondroplasia
Heterozygous Achondroplasia
Prototype of rhizomelic dwarfism! = autosomal dominant / sporadic (80%) disease with quantitatively defective endochondral bone formation; related to advanced paternal age; epiphyseal maturation + ossification unaffected
Incidence: | 1:26,000 66,000 births, most common of lethal bone dysplasias; M < F |
normal intelligence + motor function
neurologic defects
classically circus dwarfs
@ Skull
flat nasal bridge (hypoplastic base of skull)
macrocephaly + brachycephaly with enlarged bulging forehead (nonprogressive hydrocephalus)
relative prognathism
large calvarium with frontal bossing depression of nasion broad mandible constricted basicranium + small foramen magnum: communicating hydrocephalus caused by obstruction of basal cisterns + aqueduct
Cx: | apnea + sudden death (due to compression of spinal cord + lower brain stem) |
@ Chest
anteroposterior narrowing of chest short anteriorly flared concave ribs squaring of inferior scapular margin
@ Spine
hypoplastic bullet- / wedge-shaped vertebra: rounded anterior beaking of vertebra in upper lumbar spine (DDx: Hurler disease) decreased vertebral height
scalloped posteriorly concave vertebral margin scoliosis: thoracolumbar angular kyphosis (gibbus) exaggerated sacral lordosis
stenosis of lumbar spine: narrowing of interpedicular space due to laminar thickening ventrodorsal narrowing of spine due to short pedicles bulging / herniation of intervertebral disks
wide intervertebral foramina
@ Pelvis
protuberant abdomen
prominent buttocks
rolling gait from backward tilt of pelvis and hip joints
square flattened iliac bones = tombstone configuration champagne glass -shaped pelvic inlet lack of flaring of iliac wings horizontal acetabula (= flat acetabular angle) small sacrosciatic notch
@ Extremities
short stubby limbs + fingers
trident hand = separation of 2nd + 3rd digit and inability to approximate 3rd + 4th finger
limited range of motion of elbow
predominantly rhizomelic micromelia of long bones (femur, humerus): trumpet appearance of long bones = shortening with disproportionate metaphyseal flaring (actually normal width of metaphysis) short femoral necks limb bowing
ball-in-socket epiphysis = broad V-shaped distal femoral metaphysis in which epiphysis is incorporated high position of fibular head (= disproportionately long fibula) short ulna with thick proximal + slender distal end brachydactyly (short tubular bones of hand + feet), especially short proximal + middle phalanges
OB-US (diagnosable >21 27th week GA):
shortening of proximal long bones: femur length <99th percentile between 21 and 27 weeks MA increased BPD, HC, HC:AC ratio decreased FL:BPD ratio normal mineralization, no fractures normal thorax + normal cardiothoracic ratio three-pronged (= trident) hand = 2nd + 3rd + 4th finger of similarly short length without completely approximating each other (= PATHOGNOMONIC)
P.43
Cx: | (1) Hydrocephalus + syringomyelia (small foramen magnum) (2) Recurrent ear infection (poorly developed facial bones) (3) Neurologic complications (compression of spinal cord, lower brainstem, cauda equina, nerve roots): apnea and sudden death 4) Crowded dentition + malocclusion |
Prognosis: | long life |
DDx: | various mucopolysaccharidoses |
Homozygous Achondroplasia
= hereditary autosomal dominant disease with severe features of achondroplasia (disproportionate limb shortening, more marked proximally than distally)
Risk: | marriage of two achondroplasts to each other |
large cranium with short base + small face flattened nose bridge short ribs with flared ends hypoplastic vertebral bodies decreased interpedicular distance short squared innominate bones flattened acetabular roof small sciatic notch short limb bones with flared metaphyses short, broad, widely spaced tubular bones of hand
Prognosis: | often stillborn; lethal in neonatal period (from respiratory failure) |
DDx: | thanatophoric dysplasia |
Pseudoachondroplasia
= part of osteochondroplasias
Prevalence: | 4:1,000,000 |
Etiology: | mutation of genes encoding for cartilage oligomeric matrix protein (COMP) on chromosome 19 (closely related to multiple epiphyseal dysplasia) |
Age at presentation: | 2 4 years |
normal facial features and intelligence
adult height 82 130 (mean, 118) cm
disturbance of gait
joint laxity
@ Skull: normal
@ Spine
persistent oval-shaped vertebral bodies anterior beaking, platyspondyly odontoid dysplasia disk space widening
@ Extremities
short long bones with flared metaphyses small irregular flared epiphyses with delayed development medial beaking of proximal femoral neck (CHARACTERISTIC) genu valgum, genu varum, genu recurvatum shortening + widening of phalanges and metacarpals + metatarsals
@ Pelvis
widened triradiate cartilage
Cx: | premature osteoarthritis |
DDx: | (1) Achondroplasia (large head with prominent frontal region + depressed bridge of nose, normal epiphyses, trident hands) (2) Multiple epiphyseal dysplasia (near normal pelvis) (3) Spondyloepiphyseal dysplasia congenita (hip joints more affected + near normal extremities) (4) Diastrophic dwarfism (joint contractures and scoliosis at birth / in early infancy) (5) Metatrophic dwarfism (dumbbell-shaped long bones + flattened vertebrae in infancy, less epiphyseal involvement) |
Acrocephalosyndactyly
= syndrome characterized by
increased height of skull vault due to generalized craniosynostosis (= acrocephaly, oxycephaly)
syndactyly of fingers / toes
Type I | : | Apert syndrome = acrocephalosyndactyly |
Type II | : | Vogt cephalosyndactyly |
Type III | : | Acrocephalosyndactyly with asymmetry of skull + mild syndactyly |
Type IV | : | Wardenburg type |
Type V | : | Pfeiffer type |
Acroosteolysis, Familial
dominant inheritance
Age: | onset in 2nd decade; M:F = 3:1 |
sensory changes in hands + feet
destruction of nails
joint hypermobility
swelling of plantar of foot with deep wide ulcer + ejection of bone fragments
@ Skull
wormian bones craniosynostosis basilar impression protuberant occiput resorption of alveolar processes + loss of teeth
@ Spine
spinal osteoporosis fracture kyphoscoliosis + progressive decrease in height
Acromegaly
Etiology: | excess growth hormone due to eosinophilic adenoma / hyperplasia in anterior pituitary |
gigantism in children: advanced bone age + excessive height (DDx: Soto syndrome of cerebral gigantism = large skull, mental retardation, cerebral atrophy, advanced bone age)
osseous enlargement (phalangeal tufts, vertebrae) flared ends of long bone cystic changes in carpals, femoral trochanters osteoporosis @ Hand
spadelike hand
widening of terminal tufts
@ Skull
prognathism (= elongation of mandible) in few cases sellar enlargement + erosion enlargement of paranasal sinuses: large frontal sinuses (75%) calvarial hyperostosis (especially inner table) enlarged occipital protuberance
P.44
@ Vertebrae
posterior scalloping in 30% (secondary to pressure of enlarged soft tissue) anterior new bone loss of disk space (weakening of cartilage)
@ Soft tissue
heel pad >25 mm
@ Joints
premature osteoarthritis (commonly knees)
Actinomycosis
= chronic suppurative infection characterized by formation of multiple abscesses, draining sinuses, abundant granulation tissue secondary to mucosal disruption + low tissue oxygen tension
Organism: | Actinomyces israelii / naeslundii / viscosus / eriksonii, gram-positive non acid-fast anaerobic pleomorphic small filamentous bacterium with proteolytic activity, superficially resembling the morphology of a hyphal fungus (Gomori methenamine silver stain-positive filaments); closely related to mycobacteria |
Spread:
contiguous: production of proteolytic enzymes allows crossing of normal anatomic barriers
hematogenous
Histo: | mycelial form in tissue; as opportunistic pathogens rod-shaped bacterial form normally inhabits oropharynx (dental caries, gingival margins, tonsillar crypts) + GI tract |
Predisposed: | individuals with very poor dental hygiene, immunosuppressed patients |
Location: | mandibulofacial > intestinal > lung |
Clinical types:
Mandibulo- / cervicofacial actinomycosis (55%)
Cause: poor oral hygiene draining cutaneous sinuses
sulfur granules in sputum / exudate = colonies of organisms arranged in circular fashion = mycelial clumps with thin hyphae 1 2 mm in diameter
osteomyelitis of mandible (most frequent bone involved) with destruction of mandible around tooth socket no new-bone formation spread to soft tissues at angle of jaw + into neck
Abdominopelvic / ileocecal / abdominal actinomycosis (20%)
Cause: rupture / surgery of appendix; IUD use (25% of IUDs become eventually colonized with serious infections in 2 4%) Location: initially localized to cecum / appendix fever, leukocytosis, mild anemia
weight loss, nausea, vomiting
lower abdominal pain
chronic sinus in groin, vaginal discharge
yellow / brown sulfur granules on cervical Papanicolaou smear
fold thickening + ulcerations (resembling Crohn disease) rupture of abdominal viscus (usually appendix) fistula formation abscess in liver (15%), retroperitoneum, psoas muscle, pelvis, tubo-ovarian abscess (containing yellow sulfur granules = 1 2-mm colony of gram-positive bacilli) hydronephrosis (due to ureteral compression by pelvic abscess)
Pleuropulmonary / thoracic actinomycosis (15%)
Cause: aspiration of infected material from oropharynx / hematogenous spread Predisposed: alcoholics Histo: masses of PMN leukocytes containing round actinomycotic / sulfur granules surrounded by a rim of granulation tissue @ Lung
draining chest wall sinuses (spread through fascial planes)
enhancing extensive transfissural chronic segmental consolidation (acute airspace pneumonia rare); usually unilateral + upper lobe predominance cavitary lesion (abscess) with ringlike enhancement fibrotic pleuritis chronic pleural effusion / empyema CT:
central areas of low attenuation within consolidation adjacent pleural thickening
DDx: carcinoma, tuberculosis, bacterial / fungal pneumonia
@ Vertebra + ribs
destruction of vertebra with preservation of disk + small paravertebral abscess without calcification (DDx to tuberculosis: disk destroyed, large abscess with calcium) thickening of cervical vertebrae around margins destruction / thickening of ribs
Mixed organs (10%)
@ Tubular bones of hands
destructive lesion of mottled permeating type cartilage destruction + subarticular erosive defects in joints (simulating TB)
@ Skin, brain, pericardium
Dx: | anaerobic culture; species-specific antibodies |
Rx: | surgical d bridement + high doses of penicillin |
Adamantinoma
= (MALIGNANT) ANGIOBLASTOMA
= locally aggressive / malignant lesion
Histo: pseudoepithelial cell masses with peripheral columnar cells in a palisade pattern with varying amounts of fibrous stroma; areas of squamous / tubular / alveolar / vessel transformation; prominent vascularity; resembles ameloblastoma of the jaw Age: 25 50 years, commonest in 3rd 4th decade frequently history of trauma
local swelling pain
Location: middle 1/3 of tibia (90%), fibula, ulna, carpals, metacarpals, humerus, shaft of femur eccentric round osteolytic lesion with sclerotic margin, may have additional foci in continuity with major lesion (CHARACTERISTIC) may show mottled density bone expansion frequent often multiple Prognosis: tendency to recur after local excision; after several recurrences pulmonary metastases may develop DDx: fibrous dysplasia (possibly related)
P.45
Ainhum Disease
= DACTYLOLYSIS SPONTANEA
[ainhum, Brazilian tribal language = fissure, saw, sword]
Etiology: unknown Histo: hyperkeratotic epidermis with fibrotic thickening of collagen bundles below; chronic lymphocytic inflammatory reaction may be present; arterial walls may be thickened with narrowed vessel lumina Incidence: up to 2% Age: usually in males in 4th + 5th decades; Blacks (West Africa) + their American descendants; M > F deep soft-tissue groove forming on medial aspect of plantar surface of proximal phalanx with edema distally
painful ulceration may develop
Location: mostly 5th / 4th toe (rarely finger); near interphalangeal joint; mostly bilateral sharply demarcated progressive bone resorption of distal / middle phalanx with tapering of proximal phalanx to complete autoamputation (after an average of 5 years) osteoporosis
Rx: | early surgical resection of groove with Z-plasty |
DDx: | (1) Neuropathic disorders (diabetes, leprosy, syphilis) (2) Trauma (burns, frostbite) (3) Acroosteolysis from inflammatory arthritis, infection, polyvinyl chloride exposure (4) Congenitally constricting bands in amniotic band syndrome |
Amyloidosis
= extracellular deposition of a chemically diverse group of protein polysaccharides in body tissues ( 2-microglobulin); tends to form around capillaries + endothelial cells of larger blood vessels causing ultimately vascular obliteration with infarction
2-microglobulin = low-molecular-weight serum protein not filtered by standard dialysis membranes
Path: | stains with Congo red |
At risk: | patients on long-term hemodialysis |
bone pain (eg, shoulder pain)
periarticular rubbery soft-tissue swelling + stiffness (shoulders, hips, fingers):
carpal-tunnel syndrome (commonly bilateral)
Bence Jones protein (without myeloma)
Amyloid Arthropathy
= synovial-articular pattern of amyloidosis
Location: | cervical spine, hip, shoulder, elbow |
juxtaarticular soft-tissue swelling (amyloid deposited in synovium, joint capsule, tendons, ligaments) extrinsic osseous erosion mild periarticular osteoporosis subchondral cysts + well-defined sclerotic margin joint space preserved until late in course of disease subluxation of proximal humerus + femoral neck MR:
extensive deposition of abnormal soft tissue of low to intermediate signal intensity on T1WI + T2WI covering synovial membrane, filling subchondral defects, extending into periarticular tissue joint effusion
DDx: | inflammatory arthritis |
Diffuse Amyloid Marrow Deposition
generalized osteoporosis coarse trabecular pattern (DDx: sarcoidosis) pathologic collapse of vertebral body may occur
Amyloidoma
= localized destructive lesion of amyloidosis (rarest form)
Location: appendicular > axial skeleton focal medullary lytic lesion with endosteal scalloping ( secondary invasion + erosion of articular bone) Cx: pathologic fracture
Aneurysmal Bone Cyst
= expansile pathologically benign lytic lesion of bone containing thin-walled cystic cavities filled with chronic blood products; name derived from roentgen appearance
Etiology:
primary ABC (65 99%)
local circulatory disturbance as a result of trauma
secondary ABC (1 35%)
arising in preexisting bone tumor causing venous obstruction / arteriovenous fistula: giant cell tumor (39%), osteoblastoma, chondroblastoma, angioma, telangiectatic osteosarcoma, solitary bone cyst, fibrous dysplasia, xanthoma, chondromyxoid fibroma, nonossifying fibroma, metastatic carcinoma
Histo: | intraosseous arteriovenous malformation with honeycombed spaces filled with blood + lined by granulation tissue / osteoid; areas of free hemorrhage; sometimes multinucleated giant cells; solid component predominates in 5 7% |
Types:
INTRAOSSEOUS ABC
= primary cystic / telangiectatic tumor of giant cell family, originating in bone marrow cavity, slow expansion of cortex; rarely related to history of trauma
EXTRAOSSEOUS ABC
= posttraumatic hemorrhagic cyst; originating on surface of bones, erosion through cortex into marrow
Age: | peak age 16 years (range 10 30 years); in 75% <20 years; F > M |
pain of relatively acute onset with rapid increase of severity over 6 12 weeks
history of trauma
neurologic signs (radiculopathy to quadriplegia) if in spine
Location: | (a) spine (12 30%) with slight predilection for posterior elements; thoracic > lumbar > cervical spine (22%); involvement of vertebral body (40 90%); may involve two contiguous vertebrae (25%) (b) long bones: eccentric in metaphysis of femur, tibia, humerus, fibula; pelvis |
P.46
purely lytic eccentric radiolucency aggressive expansile ballooning lesion of soap-bubble pattern + thin internal trabeculations rapid progression within 6 weeks to 3 months sclerotic inner portion almost invisible thin cortex (CT shows integrity) tumor respects epiphyseal plate no periosteal reaction (except when fractured)
CT:
blood-filled sponge = fluid-fluid / hematocrit levels due to blood sedimentation (in 10 35%)
MR:
multiple cysts of different signal intensity representing different stages of blood by-products: heterogeneous fluid-fluid levels within loculations reflecting hemorrhage with sedimentation
low-signal intensity rim = intact thickened periosteal membrane heterogeneous enhancement
NUC:
doughnut sign = peripheral increased uptake (64%)
Angio:
hypervascularity in lesion periphery (in 75%)
Prognosis: | 20 30% recurrence rate |
Rx: | preoperative embolotherapy; complete resection; radiation therapy (subsequent sarcoma possible) |
Cx: | (1) pathologic fracture (frequent) (2) extradural block with paraplegia |
DDx: | (1) Giant cell tumor (particularly in spine) (2) Hemorrhagic cyst (end of bone / epiphysis, not expansile) (3) Enchondroma (4) Metastasis (renal cell + thyroid carcinoma) (5) Plasmacytoma (6) Chondro- and fibrosarcoma (7) Fibrous dysplasia (8) Hemophilic pseudotumor (9) Hydatid cyst |
Angiomatosis
= diffuse infiltration of bone / soft tissue by hemangiomatous / lymphangiomatous lesions
Age: | first 3 decades of life |
May be associated with:
chylothorax, chyloperitoneum, lymphedema, hepatosplenomegaly, cystic hygroma
OSSEOUS ANGIOMATOSIS (30 40%)
indolent course
Location: femur > ribs > spine > pelvis > humerus > scapula > other long bones > clavicle osteolysis with honeycomb / latticework ( hole-within-hole ) appearance may occur on both sides of joint DDx: solitary osseous hemangioma
CYSTIC ANGIOMATOSIS
= extensive involvement of bone
Histo: endothelium-lined cysts in bone Age: peak 10 15 years; range of 3 months to 55 years Location: long bones, skull, flat bones multiple osteolytic metaphyseal lesions of 1 2 mm to several cm with fine sclerotic margins + relative sparing of medullary cavity may show overgrowth of long bone endosteal thickening sometimes associated with soft-tissue mass phleboliths chylous pleural effusion suggests fatal prognosis DDx: (other polyostotic diseases such as) histiocytosis X, fibrous dysplasia, metastases, Gaucher disease, congenital fibromatosis, Maffucci syndrome, neurofibromatosis, enchondromatosis
SOFT-TISSUE ANGIOMATOSIS (60 70%)
= VISCERAL ANGIOMATOSIS
poor prognosis
ANGIOMATOUS SYNDROMES
Maffucci syndrome
Osler-Weber-Rendu syndrome
Klippel-Trenaunay-Weber disease
Kasabach-Merritt syndrome
Gorham disease
Angiosarcoma
= aggressive vascular malignancy with frequent local recurrence + distant metastasis
Histo: | vascular channels surrounded by hemangiomatous / lymphomatous cellular elements with high degree of anaplasia |
Age: | M:F = 2:1 |
Associated with: | Stewart-Treves syndrome |
= angiosarcoma with chronic lymphedema developing in postmastectomy patients
Location: | skin (33%); soft tissue (24%); bone (6%): tibia (23%), femur (18%), humerus (13%), pelvis (7%) |
DDx: | hemangioendothelioma, hemangiopericytoma |
Ankylosing Spondylitis
= autoimmune disease of unknown etiology primarily affecting axial skeleton
Age: | 15 35 years; M:F = 3:1 10:1; Caucasians:Blacks = 3:1 |
Associated with: | (1) ulcerative colitis, regional enteritis (2) iritis in 25% (3) aortic insufficiency + atrioventricular conduction defect |
HLA-B 27 positive in 96%
insidious onset of low back pain + stiffness
Path: involves synovial + cartilaginous joints and sites of ligamentous attachment Location:
axial skeleton: sacroiliac joints, thoracolumbar + lumbosacral junctions
HALLMARK is sacroiliac joint involvement!
peripheral skeleton (10 20%): sternal joint, symphysis pubis, hip, glenohumeral joint
tendinous insertions in pelvis + proximal femur
Temporal course: initial abnormalities of sacroiliac joints + thoracolumbar junction with gradual involvement of remainder of spine
P.47
@ Skull
temporomandibular joint space narrowing, erosions, osteophytosis
@ Hand (30%)
Target area: MCP, PIP, DIP exuberant osseous proliferation osteoporosis, joint space narrowing, osseous erosions (deformities less striking than in rheumatoid arthritis)
@ Sacroiliac joint / symphysis pubis
initially sclerosis of joint margins primarily on iliac side (bilateral + symmetric late in disease, may be unilateral + asymmetric early in disease) later irregularities + widening of joint (cartilage destruction) bony fusion
@ Pelvis
periostitic whiskering : ischial tuberosity, iliac crest, ischiopubic rami, greater femoral trochanter, external occipital protuberance, calcaneus
@ Spine
squaring = straightened / convex anterior vertebral margins = erosive osteitis of anterior corners shiny corner = reactive sclerosis of corners of vertebral bodies diskitis = erosive abnormalities of diskovertebral junction diskal ballooning = biconvex shape of intervertebral disk related to osteoporotic deformity diskal calcification marginal syndesmophyte formation = thin vertical radiodense spicules bridging the vertebral bodies = ossification of outer fibers of annulus fibrosus (NOT anterior longitudinal ligament): bamboo spine on AP view = undulating contour due to syndesmophytosis Cx: prone to fracture resulting in pseudarthrosis
asymmetric erosions of laminar + spinous processes of lumbar spine ossification of supraspinous + interspinous ligaments: dagger sign = single radiodense line on AP view trolley-track sign on AP view = central line of ossification with two lateral lines of ossification (apophyseal joint capsules)
apophyseal + costovertebral joint ankylosis (on oblique views) dorsal arachnoid diverticula in lumbar spine with erosion of posterior elements (Cx: cauda equina syndrome) atlantoaxial subluxation
@ Chest
Incidence: 1% of patients with ankylosing spondylitis Histo: interstitial + pleural fibrosis with foci of dense collagen deposition, NO granulomas bone manifestations obvious + severe
Location: apices / upper lung fields
sternomanubrial joint irregularities + sclerosis uni- / bilateral coarse upper lobe pulmonary fibrosis with upward retraction of hila (DDx: tuberculosis) reticulonodular progressively confluent opacities in lung apices apical bullae + cavitation (mimicking TB) HRCT:
peripheral interstitial lung disease bronchiectasis paraseptal emphysema apical fibrosis
Cx: superinfection, especially with aspergillosis (mycetoma formation) / atypical mycobacteria DDx: other causes of pulmonary apical fibrosis (primary infection by fungi / mycobacteria; cancer)
@ Cardiovascular
Aortitis (5%) of ascending aorta aortic valve insufficiency
Prognosis: 20% progress to significant disability; occasionally death from cervical spine fracture / aortitis DDx: (1) Reiter syndrome (unilateral asymmetric SI joint involvement, paravertebral ossifications) (2) Psoriatic arthritis (unilateral asymmetric SI joint involvement, paravertebral ossifications)
(3) Inflammatory bowel disease
(4) Sternocostoclavicular hyperostosis (pustulosis palmaris et plantaris)
Anterior Tibial Bowing
= WEISMANN-NETTER SYNDROME
= congenital painless nonprogressive bilateral anterior leg bowing
Age: beginning in early childhood may be accompanied by mental retardation, goiter, anemia
anterior bowing of tibia + fibula, bilaterally, symmetrically at middiaphysis thickening of posterior tibial + fibular cortices minor radioulnar bowing kyphoscoliosis extensive dural calcification DDx: Luetic saber shin (bowing at lower end of tibia + anterior cortical thickening)
Apert Syndrome
= ACROCEPHALOSYNDACTYLY type I
Frequency: | 5.5:1,000,000 neonates |
Etiology: | autosomal dominant with incomplete penetrance; sporadic (in majority) |
Associated with CNS anomalies:
megalocephaly, gyral abnormalities, hypoplastic white matter, heterotopic gray matter, frontal encephalocele, corpus callosal agenesis, Kleeblattsch del, cleft palate, ventriculomegaly (? related to skull base hypoplasia, rarely progressive)
IQ varies depending on CNS anomalies (in 50% normal)
otitis media (high prevalence)
bifid uvula
conductive hearing loss (common due to external + middle ear malformations)
@ Skull
downturned mouth
brachycephalic skull (due to coronal craniosynostosis) + flat occiput widened metopic + sagittal sutures extending from glabella to posterior fontanel (closing between 2 to 4 years) hypoplastic / retruded midface: hypertelorism shallow orbits with proptosis underdeveloped paranasal sinuses underdeveloped maxilla with prognathism
P.48
high pointed arch of palate prominent vertical crest in middle of forehead (increased intracranial pressure) V-shaped anterior fossa due to elevation of lateral margins of lesser sphenoid sella may be enlarged stylohyoid ligament calcification (38 88%) cervical spine fusion (in up to 71%), commonly of 5th and 6th vertebrae choanal stenosis
@ Hand & feet
severe symmetric syndactyly = fusion of distal portions of phalanges, metacarpals / carpals (most often of 2nd, 3rd + 4th digit) absence of middle phalanges missing / supernumerary carpal / tarsal bones pseudarthroses
@ GU (10%)
cryptorchidism
hydronephrosis polycystic kidneys (rare) bicornuate uterus (rare)
Arteriovenous Fistula of Bone
Etiology: | (a) acquired (usually gunshot wound) (b) congenital |
Location: | lower extremity most frequent |
soft-tissue mass presence of large vessels phleboliths (DDx: long-standing varicosity) accelerated bone growth cortical osteolytic defect (= pathway for large vessels into medulla) increased bone density
Arthrogryposis
= ARTHROGRYPOSIS MULTIPLEX CONGENITA
= nonprogressive congenital syndrome complex characterized by poorly developed + contracted muscles, deformed joints with thickened periarticular capsule and intact sensory system
Pathophysiology: | congenital / acquired defect of motor unit (anterior horn cells, nerve roots, peripheral nerves, motor end plates, muscle) early in fetal life with immobilization of joints at various stages in their development |
Cause: | ? neurotropic agents, toxic chemicals, hard drugs, hyperthermia, neuromuscular blocking agents, mytotic abnormalities, mechanical immobilization |
Incidence: | 0.03% of newborn infants; 5% risk of recurrence in sibling |
Path: | diminution in size of muscle fibers + fat deposits in fibrous tissue |
Associated with: | (1) neurogenic disorders (90%) (2) myopathic disorders (3) skeletal dysplasias (4) intrauterine limitation of movement (myomata, amniotic band, twin, oligohydramnios) (5) connective tissue disorders |
Distribution: | all extremities (46%), lower extremities only (43%), upper extremities only (11%); peripheral joints >> proximal joints; symmetrical |
clubfoot
congenital dislocation of hip
claw hand
diminished muscle mass
skin webs
flexion + extension contractures osteopenia pathologic fractures congenital dislocation of hip carpal coalition vertical talus calcaneal valgus deformity
Asphyxiating Thoracic Dysplasia
= JEUNE DISEASE
= autosomal recessive dysplasia
Incidence: 100 cases Associated with: renal anomalies (hydroureter), PDA respiratory distress due to reduced thoracic mobility (abdominal breathing) + frequent pulmonary infections
progressive renal failure + hypertension
@ Chest
markedly narrow + elongated bell-shaped chest: chest diameter significantly decreased compared with that of the abdomen
normal size of heart leaving little room for lungs horizontal clavicles at level of 6th cervical vertebra short horizontal ribs + irregular bulbous costochondral junction
@ Pelvis
trident pelvis (retardation of ossification of triradiate cartilage) small iliac wings flared + shortened in cephalocaudal diameter ( wineglass pelvis) short ischial + pubic bones reduced acetabular angle + acetabular spurs premature ossification of capital femoral epiphysis
@ Extremities
rhizomelic brachymelia (humerus, femur) = long bones shorter + wider than normal metaphyseal irregularity postaxial hexadactyly (occasionally) shortening of distal phalanges + cone-shaped epiphyses in hands + feet proximal humeral + femoral epiphyses ossified at birth (frequently)
@ Kidneys
medullary cystic renal disease = enlarged kidneys with linear streaking on nephrogram (in adulthood) OB-US:
proportionate shortening of long bones small thorax with decreased circumference increased cardiothoracic ratio occasionally polydactyly polyhydramnios
Prognosis: neonatal death in 80% (respiratory failure + infections) DDx: Ellis-van Creveld syndrome
Avascular Necrosis
= AVN = OSTEONECROSIS = ASEPTIC NECROSIS
= consequence of interrupted blood supply to bone with death of cellular elements
Terminology (now often used interchangeably):
Osteonecrosis = ischemic bone death due to sepsis
Avascular necrosis = avascular and aseptic bone necrosis
Ischemic necrosis = necrosis of epiphyseal + subarticular bone
Bone infarction = necrosis of metaphyseal + diaphyseal bone
Histo:
cellular ischemia leading to death of hematopoietic cells (in 6 12 hours), osteocytes (in 12 48 hours) and lipocytes (in 2 5 days)
necrotic debris in intertrabecular spaces + proliferation and infiltration by mesenchymal cells + capillaries
mesenchymal cells differentiate to osteoblasts on the surface of dead trabeculae synthesizing new bone layers + resulting in trabecular thickening
Pathogenesis:
obstruction of extra- and intraosseous vessels by arterial embolism, venous thrombosis, traumatic disruption, external compression (increased marrow space pressure)
cumulative stress from cytotoxic factors
Cause:
NO predisposing factors in 25%!
Traumatic interruption of arteries
@ femoral head:
Femoral neck fracture (60 75%)
Dislocation of hip joint (25%)
Slipped capital femoral epiphysis (15 40%)
@ carpal scaphoid:
4 6 months after fracture (in 10 15%), in 30 40% of nonunion of scaphoid fracture
Site: proximal fragment (most common)
@ humeral head (infrequent)
@ talus (after talar neck fracture)
Embolization of arteries
Hemoglobinopathy: sickle-cell disease
Nitrogen bubbles: Caisson disease
Fat: ethanol abuse with pancreatitis
Vasculitis
Collagen-vascular disease: SLE
Radiation exposure
Abnormal accumulation of cells
Lipid-containing histiocytes: Gaucher disease
Fat cells: steroid therapy
Idiopathic
Spontaneous osteonecrosis of knee
Legg-Calv -Perthes disease
Freiberg disease (repetitive microtrauma)
mnemonic: | PLASTIC RAGS |
Pancreatitis, Pregnancy
Legg-Perthes disease, Lupus erythematosus
Alcoholism, Atherosclerosis
Steroids
Trauma (femoral neck fracture, hip dislocation)
Idiopathic (Legg-Perthes disease), Infection
Caisson disease, Collagen disease (SLE)
Rheumatoid arthritis, Radiation treatment
Amyloid
Gaucher disease
Sickle cell disease
mnemonic: | GIVE INFARCTS |
Gaucher disease
Idiopathic (Legg-Calv -Perthes, K hler, Chandler)
Vasculitis (SLE, polyarteritis nodosa, rheumatoid arthritis)
Environmental (frostbite, thermal injury)
Irradiation
Neoplasia (-associated coagulopathy)
Fat (prolonged corticosteroid use increases marrow)
Alcoholism
Renal failure + dialysis
Caisson disease
Trauma (femoral neck fracture, hip dislocation)
Sickle cell disease
Location: | femoral head (most common), humeral head, femoral condyles |
Radiography:
dense osteonecrotic bone (due to lack of resorption relative to healthy osteopenic bone + new bone laid down over necrotic trabeculae) radiolucent rim around area of osteonecrosis (due to absorption around necrotic bone)
Avascular Necrosis of Hip
Involvement of one hip increases risk to contralateral hip to 70%! Age: 20 50 years hip / groin / thigh / knee pain
limited range of motion
Plain film (positive only several months after symptoms):
subtle relative sclerosis of femoral head secondary to resorption of surrounding vascularized bone (earliest sign) radiolucent crescent parallel to articular surface in weight-bearing portion secondary to subchondral structural collapse of necrotic segment Site: anterosuperior portion of femoral head (best seen on frog leg view) preservation of joint space (DDx: arthritis) flattening of articular surface increased density of femoral head (compression of bony trabeculae following microfracture of nonviable bone, calcification of dendritic marrow, creeping substitution = deposition of new bone)
Classification (Steinberg):
P.49
P.50
Stage 0 | = | normal |
Stage I | = | normal / barely detectable trabecular mottling; abnormal bone scan / MRI |
Stage IIA | = | focal sclerosis + osteopenia |
Stage IIB | = | distinct sclerosis + osteoporosis + early crescent sign |
Stage IIIA | = | subchondral undermining ( crescent sign ) + cyst formation |
Stage IIIB | = | mild alteration in femoral head contour / subchondral fracture + normal joint space |
Stage IV | = | marked collapse of femoral head + significant acetabular involvement |
Stage V | = | joint space narrowing + acetabular degenerative changes |
NUC (80 85% sensitivity):
Bone marrow imaging (with radiocolloid) more sensitive than bone imaging (with diphosphonates) More sensitive than plain films in early AVN (evidence of ischemia seen as much as 1 year earlier) Less sensitive than MR
Technique: | imaging improved with double counts, pinhole collimation |
early: cold = photopenic defect (interrupted blood supply) late: doughnut sign = cold spot surrounded by increased uptake secondary to capillary revascularization + new-bone synthesis
degenerative osteoarthritis
CT (utilized for staging of known disease):
staging upgrades in 30% compared with plain films
MR (90 100% sensitive, 85% specific for symptomatic disease):
Prevalence of clinically occult disease: | 6% |
MR imaging changes reflect the death of marrow fat cells (not death of osteocytes with empty lacunae)! Sagittal images particularly useful! EARLY AVN:
decreased Gd-enhancement on short-inversion-recovery (STIR) images (very early) low-signal intensity band with sharp inner interface + blurred outer margin on T1WI within 12 48 hours (= mesenchymal + fibrous repair tissue, amorphous cellular debris, thickened trabecular bone) seen as band extending to subchondral bone plate
complete ring (less frequent)
double-line sign on T2WI (in 80%) [MORE SPECIFIC] = juxtaposition of inner hyperintense band (granulation tissue) + outer hypointense band (chemical shift artifact / fibrosis + sclerosis)
ADVANCED AVN:
pseudohomogeneous edema pattern = inhomogeneous large areas of mostly decreased signal intensity on T1WI hypo- to hyperintense lesion on T2WI contrast-enhancement of interface + surrounding marrow + within lesion
SUBCHONDRAL FRACTURE:
predilection for anterosuperior portion of femoral head (sagittal images!) MRI Classification of Aseptic Necrosis Mitchell Classification
Stage T1 T2 Analogous to A high intermediate fat B high high subacute blood C low high fluid / edema D low low fibrosis cleft of low-signal intensity running parallel to the subchondral bone plate within areas of fatlike signal intensity on T1WI hyperintense band (= fracture cleft filled with articular fluid / edema) within the intermediate- or low-signal-intensity necrotic marrow on T2WI lack of enhancement within + around fracture cleft
EPIPHYSEAL COLLAPSE:
focal depression of subchondral bone Cx: early osteoarthritis through collapse of femoral head + joint incongruity in 3 5 years if left untreated Rx: (1) core decompression (for grade 0 II): most successful with <25% involvement of femoral head (2) osteotomy (for grade 0 II)
(3) arthroplasty / arthrodesis / total hip replacement (for grade >III)
DDx: bone marrow edema (ill-delimited marrow changes, no reactive interface); epiphyseal fracture (speckled / linear hypointense areas, focal depression of epiphyseal contour); spondyloarthropathy
Blount Disease
= TIBIA VARA
= avascular necrosis of medial tibial condyle
Age: >6 years limping, lateral bowing of leg
medial tibial condyle enlarged + deformed (DDx: Turner syndrome) irregularity of metaphysis (medially + posteriorly prolonged with beak)
Calv -K mmel-Verneuil Disease
= VERTEBRAL OSTEOCHONDROSIS = VERTEBRA PLANA
= avascular necrosis of vertebral body
Age: 2 15 years uniform collapse of vertebral body into flat thin disk increased density of vertebra neural arches NOT affected disks are normal with normal intervertebral disk space intravertebral vacuum cleft sign (PATHOGNOMONIC) DDx: eosinophilic granuloma, metastatic disease
Freiberg Disease
[Albert Henry Freiberg (1868 1940), orthopedic surgeon in Cincinnati, Ohio]
= osteochondrosis of head of 2nd (3rd / 4th) metatarsal
Age: | 10 18 years; M:F = 1:3 |
metatarsalgia, swelling, tenderness
Early:
flattening, increased density, cystic lesions of metatarsal head widening of metatarsophalangeal joint
Late:
osteochondral fragment sclerosis + flattening of metatarsal head increased cortical thickening
Kienb ck Disease
= LUNATOMALACIA
[Robert Kienb ck (1871 1953), radiologist in Vienna, Austria]
= avascular necrosis of lunate bone
P.51
Predisposed: individuals engaged in manual labor with repeated/single episode of trauma Age: 20 40 years Associated with: ulna minus variant (short ulna) in 75% progressive pain + soft-tissue swelling of wrist
Location: uni- > bilateral (usually right hand) initially normal radiograph osteonecrotic fracture of carpal lunate increased density + altered shape + collapse of lunate Cx: scapholunate separation, ulnar deviation of triquetrum, degenerative joint disease in radiocarpal / midcarpal compartments Rx: ulnar lengthening / radial shortening, lunate replacement
K hler Disease
= avascular necrosis of tarsal scaphoid
Age: 3 10 years; boys irregular outline fragmentation disklike compression in AP direction increased density joint space maintained decreased / increased uptake on radionuclide study
Legg-Calv -Perthes Disease
= COXA PLANA
= idiopathic avascular necrosis of femoral head in children; one of the most common sites of AVN;
in 5 10% bilateral
Age: (a) 2 12 (peak, 4 8) years: M:F = 5:1 (b) adulthood: Chandler disease
Cause: trauma in 30% (subcapital fracture, epiphyseolysis, esp. posterior dislocation), closed reduction of congenital hip dislocation, prolonged interval between injury and reduction Pathophysiology:
insufficient femoral head blood supply (epiphyseal plate acts as a barrier in ages 4 10; ligamentum teres vessels become nonfunctional; blood supply is from medial circumflex artery + lateral epiphyseal artery only)
Stages:
I = histologic + clinical diagnosis without radiographic findings II = sclerosis cystic changes with preservation of contour + surface of femoral head III = loss of structural integrity of femoral head IV = in addition loss of structural integrity of acetabulum 1 week 6 months (mean 2.7 months) duration of symptoms prior to initial presentation: limp, pain
NUC (may assist in early diagnosis):
decreased uptake (early) in femoral head = interruption of blood supply increased uptake (late) in femoral head = revascularization + bone repair
degenerative osteoarthritis
increased acetabular activity with associated degenerative joint disease
X-RAY:
Early signs:
femoral epiphysis smaller than on contralateral side (96%) sclerosis of femoral head epiphysis (sequestration + compression) (82%) slight widening of joint space due to thickening of cartilage, failure of epiphyseal growth, presence of joint fluid, joint laxity (60%) ipsilateral bone demineralization (46%) alteration of pericapsular soft-tissue outline due to atrophy of ipsilateral periarticular soft tissues (73%) rarefaction of lateral + medial metaphyseal areas of neck NEVER destruction of articular cortex as in bacterial arthritis
Late signs:
delayed osseous maturation of a mild degree radiolucent crescent line of subchondral fracture = small archlike subcortical lucency (32%) subcortical fracture on anterior articular surface (best seen on frog leg view) femoral head fragmentation femoral neck cysts (from intramedullary hemorrhage in response to stress fractures) loose bodies (only found in males)
Regenerative signs:
coxa plana = flattened collection of sclerotic fragments (over 18 months) coxa magna = remodeling of femoral head to become wider + flatter in mushroom configuration to match widened metaphysis + epiphyseal plate
CT:
loss of asterisk sign (= starlike pattern of crossing trabeculae in center of femoral head) with distortion of asterisk and extension to surface of femoral head
MR:
normal signal intensity in marrow of femoral epiphysis replaced by low signal intensity on T1WI + high signal intensity on T2WI = asterisk sign double-line sign (80%) = sclerotic nonsignal rim producing line between necrotic + viable bone edged by a hyperintense rim of granulation tissue fluid within fracture plane hip joint incongruity: lateral femoral head uncovering, labral inversion, femoral head deformity
Cx: severe degenerative joint disease in early adulthood Rx: bed rest, abduction bracing (to reduce stress on infarcted head)
Panner Disease
(NOT osteonecrosis)
= benign self-limited disorder of fragmented ossification in epiphysis of capitellum
Age: children 7 12 years of age
Preiser Disease
= nontraumatic osteonecrosis of scaphoid
P.52
Spontaneous Osteonecrosis of Knee
= SONK
Cause: | ? meniscal tear (78%), trauma with resultant microfractures, vascular insufficiency, degenerative joint disease, severe chondromalacia, gout, rheumatoid arthritis, joint bodies, intraarticular steroid injection (45 85%) |
Age: | 7th decade (range 13 83 years) |
acute onset of pain
Location: | weight-bearing medial condyle more toward epicondylus (95%), lateral condyle (5%), may involve tibial plateau |
radiographs usually normal (within 3 months after onset) positive bone scan within 5 weeks (most sensitive) flattening of weight-bearing segment of medial femoral epicondyle radiolucent focus in subchondral bone + peripheral zone of osteosclerosis horizontal subchondral fracture (within 6 9 months) + osteochondral fragment periosteal reaction along medial side of femoral shaft (30 50%) Cx: osteoarthritis
Talar AVN
Fractures involving the talar body have a higher prevalence of AVN Risk of AVN:
nondisplaced fracture
- talar neck fracture (Hawkins type I) 0 15% fracture with dislocation / subluxation of:
- subtalar joint (Hawkins type II) 20 50% - ankle + subtalar joints (Hawkins type III) almost 100% - subtalar + tibiotalar + talonavicular joints (Hawkins type IV fracture) 100%
increase in talar dome opacity / sclerosis deformity + articular collapse + bone fragmentation absent Hawkins sign = thin subchondral radiolucent line along talar dome (due to disuse osteopenia) indicates an adequate blood supply
Basal Cell Nevus Syndrome
= NEVOID BASAL CELL CARCINOMA SYNDROME = GORLIN SYNDROME
= syndrome of autosomal dominant inheritance characterized by
multiple cutaneous basal cell carcinomas during childhood
odontogenic keratocysts of mandible
ectopic calcifications
skeletal anomalies
multiple nevoid basal cell carcinomas (nose, mouth, chest, back) at mean age of 19 years; after puberty aggressive, may metastasize
pitlike defects in palms + soles
mental retardation
Association: | high incidence of medulloblastoma in children; ovarian fibroma (in 17%); cardiac fibroma (in 14%) |
@ mandibular hypoplasia:
multiple mandibular + maxillary cysts (dentigerous cysts + ectopic dentition)
anomalies of upper 5 ribs: forked = bifid rib (most commonly 4th rib) agenesis / supernumerary ribs fusion of adjacent ribs dysplastic distorted ribs
bifid spinous processes, spina bifida scoliosis (cervical + upper thoracic) hemivertebrae + block vertebrae Sprengel deformity (scapula elevated, hypoplastic, bowed) deficiency of lateral clavicle brachydactyly extensive calcification of falx + tentorium ectopic calcifications of subcutaneous tissue, ovaries, sacrotuberous ligaments, mesentery bony bridging of sella turcica macrocephaly
Battered Child Syndrome
= CAFFEY-KEMPE SYNDROME = CHILD ABUSE = PARENT -INFANT TRAUMATIC STRESS SYNDROME = NON-ACCIDENTAL TRAUMA
Most common cause of serious intracranial injuries in children <1 year of age; 3rd most common cause of death in children after sudden infant death syndrome + true accidents Prevalence: 1.7 million cases reported + 833,000 substantiated in United States in 1990 (45% neglected children, 25% physically abused, 16% sexually abused children); resulting in 2,500 5,000 deaths/year; 5 10% of children seen in emergency rooms Age: usually <2 years skin burns, bruising, lacerations, hematomas (SNAT = suspected nonaccidental trauma)
@ Skeletal trauma (50 80%)
Site: multiple ribs, costochondral / costovertebral separation, acromion, skull, anterior-superior wedging of vertebra, tibia, metacarpus Unusual sites: transverse fracture of sternum, lateral end of clavicles, scapula, vertebral compression, vertebral fracture dislocation, disk space narrowing, spinous processes Other clues: bilateral acute fractures, fractures of lower extremities in children not yet walking multiple asymmetric fractures in different stages of healing (repeated injury = HALLMARK) exuberant callus formation at fracture sites avulsion fracture of ligamentous insertion; frequently seen without periosteal reaction @ Epiphysis
separation of distal epiphysis
@ Metaphysis
marked irregularity + fragmentation of metaphyses (DDx: osteochondritis stage of congenital syphilis; infractions of scurvy) corner fracture (11%) = bucket-handle fracture = avulsion of an arcuate metaphyseal fragment overlying the lucent epiphyseal cartilage
P.53
Cause: sudden twisting motion of extremity (periosteum easily pulled away from diaphysis but tightly attached to metaphysis) Location: knee, elbow, distal tibia, fibula, radius, ulna
@ Diaphysis
isolated spiral fracture (15%) of diaphysis secondary to external rotatory force applied to femur / humerus extensive periosteal reaction from large subperiosteal hematoma apparent after 7 14 days following injury (DDx: scurvy, copper deficiency) cortical hyperostosis extending to epiphyseal plate (DDx: not in infantile cortical hyperostosis)
@ Head trauma (13 25%)
Most common cause of death + physical disability! Impact injury with translational force: skull fracture (flexible calvaria + meninges decrease likelihood of skull fractures), subdural hematoma, brain contusion, cerebral hemorrhage, infarction, generalized edema
Whiplash injury with rotational force: shearing injuries + associated subarachnoid hemorrhage
bulging fontanels, convulsions
ocular lesions, retinal detachment
Skull film (associated fracture in 1%):
linear fracture > comminuted fracture > diastases (conspicuously absent)
CT:
subdural hemorrhage (most common): interhemispheric location most common subarachnoid hemorrhage epidural hemorrhage (uncommon) cerebral edema (focal, multifocal, diffuse) acute cerebral contusion as ovoid collection of intraparenchymal blood with surrounding edema
MR:
More sensitive in identifying hematomas of differing ages white matter shearing injuries as areas of prolonged T1 + T2 at corticomedullary junction, centrum semiovale, corpus callosum
@ Viscera (3%)
Second leading cause of death in child abuse
Cause: crushing blow to abdomen (punch, kick) Age: often >2 years small bowel / gastric rupture hematoma of duodenum / jejunum contusion / laceration of lung, pancreas, liver, spleen, kidneys traumatic pancreatic pseudocyst
Cx: | (1) Brain atrophy (up to 100%) (2) Infarction (50%) (3) Subdural hygroma (4) Encephalomalacia (5) Porencephaly |
DDx: | normal periostitis of infancy, long-term ventilator therapy in prematurity, osteogenesis imperfecta, congenital insensitivity to pain, infantile cortical hyperostosis, Menkes kinky hair syndrome, Schmid-type chondrometaphyseal dysplasia, scurvy, congenital syphilitic metaphysitis |
Benign Cortical Defect
= developmental intracortical bone defect
Age: | usually 1st 2nd decade; uncommon in boys <2 years of age; uncommon in girls <4 years of age |
asymptomatic Site: metaphysis of long bone well-defined intracortical round / oval lucency usually <2 cm long sclerotic margins
Cx: | pathologic / avulsion fracture following minor trauma (infrequent) |
Prognosis: | (1) Spontaneous healing resulting in sclerosis / disappearance (2) Ballooning of endosteal surface of cortex = fibrous cortical defect (3) Medullary extension resulting in nonossifying fibroma |
Bone Infarct
Etiology:
Occlusion of vessel:
thrombus: thromboembolic disease, sickle cell disease (SS + SC hemoglobin), polycythemia rubra vera
fat: pancreatitis (intramedullary fat necrosis from circulating lipase), alcoholism
gas: Caisson disease, astronauts
Vessel wall disease:
Arteritis: SLE, rheumatoid arthritis, polyarteritis nodosa, sarcoidosis
Arteriosclerosis
Vascular compression by deposition of:
fat: corticosteroid therapy (eg, renal transplant, Cushing disease)
blood: trauma (fractures + dislocations)
inflammatory cells: osteomyelitis, infection, histiocytosis X
edema: radiation therapy, hypothyroidism, frostbite
substances: Gaucher disease (vascular compression by lipid-filled histiocytes), gout
Others: idiopathic, hypopituitarism, pheochromocytoma (microscopic thrombotic disease), osteochondroses
Medullary Infarction
Nutrient artery is the sole blood supply for diaphysis!
Location: | distal femur, proximal tibia, iliac wings, ribs, humeri |
Acute phase:
NO radiographic changes without cortical involvement area of rarefaction infarcted area hypointense on T1WI + hyperintense on T2WI bone marrow scan: diminished uptake in medullary RES for long period of time bone scan: photon-deficient lesion within 24 48 hours; increased uptake after collateral circulation established
Healing phase (complete healing / fibrosis / calcification):
demarcation by zone of serpiginous / linear calcification + ossification parallel to cortex dense bone indicating revascularization focal lesion with fatty marrow signal intensity centrally + surrounding hypointense rim (corresponding to reactive / sclerotic bone)
P.54
Cortical Infarction
Requires compromise of (a) nutrient artery and (b) periosteal vessels! Age: particularly in childhood where periosteum is easily elevated by edema avascular necrosis = osteonecrosis osteochondrosis dissecans
Cx: | (1) Growth disturbances cupped / triangular / coned epiphyses H-shaped vertebral bodies (2) Fibrosarcoma (most common), malignant fibrous histiocytoma, benign cysts (3) Osteoarthritis |
Bone Island
= ENOSTOSIS = ENDOSTEOMA = COMPACT ISLAND
= FOCAL SCLEROSIS = SCLEROTIC BONE ISLAND
= CALCIFIED MEDULLARY DEFECT
= focal lesion of densely sclerotic (compact) bone nesting within spongiosa
Age: | any age (mostly 20 80 years of age); grows more rapidly in children |
Histo: | nest of lamellar compacted bone with haversian system embedded within medullary canal |
Pathogenesis: | ? misplaced cortical hamartoma,? developmental error of endochondral ossification as a coalescence of mature bone trabeculae with failure to undergo remodeling; not inherited |
asymptomatic | |
Location: | ilium + proximal femur (88 92%), ribs, spine (1 14%), humerus, phalanges (not in skull) |
round / oval / oblong solitary osteoblastic lesion with abrupt transition to surrounding normal trabecular bone long axis of bone island parallels long axis of bone usually 2 10 mm in size; lesion >2 cm in longest axis = giant bone island brush border = thorny radiations = sharply demarcated margins with feathery peripheral radiations (HALLMARK) blending with trabeculae of surrounding spongiosa may show activity on bone scan, esp. if large (33%) may demonstrate slow growth / decrease in size (32%) NO involvement of cortex / radiolucencies / periosteal reaction
Prognosis: | may increase to 8 12 cm over years (40%); may decrease / disappear |
DDx: | (1) Osteoblastic metastasis (aggressive, break through cortex, periosteal reaction) (2) Low-grade osteosarcoma (cortical thickening, extension beyond medullary cavity) (3) Osteoid osteoma (pain relieved by aspirin, nidus) (4) Benign osteoblastoma (5) Involuted nonossifying fibroma replaced by dense bone scar (6) Eccentric focus of monostotic fibrous dysplasia (7) Osteoma (surface lesion) |
Brucellosis
= multisystemic zoonosis of worldwide distribution; endemic in Saudi Arabia, Arabian Peninsula, South America, Spain, Italy (secondary to ingestion of raw milk / milk products)
Organism: | small gram-negative nonmotile, nonsporing, aflagellate, nonencapsulated coccobacilli: Brucella abortus, B. suis, B. canis, B. melitensis |
Histo: | small intracellular pathogens shed in excreta of infected animals (urine, stool, milk, products of conception) cause small noncaseating granuloma within RES |
Location: | commonest site of involvement is reticulo-endothelial system; musculoskeletal system |
1 3 weeks between initial infection + symptoms Radiologic evidence of disease in 69% of symptomatic sites!
Brucellar spondylitis (53%)
Age: 40 years is average age at onset pain, localized tenderness, radiculopathy, myelopathy
Location: lumbar (71%) > thoracolumbar (10%) > lumbosacral (8%) > cervical (7%) > thoracic (4%) focal form
bone destruction at diskovertebral junction (anterior aspect of superior endplate) associated with bone sclerosis + anterior osteophyte formation + small amount of gas
diffuse form: entire vertebral endplate / whole vertebral body affected with spread to adjacent disks + vertebral bodies
bone destruction associated with sclerosis small amount of disk gas (25 30%) obliteration of paraspinal muscle-fat planes no / minimal epidural extension DDx: TB (paraspinal abscess, gibbus)
@ Extraspinal disease
Brucellar synovitis (81%)
Location: knee > sacroiliac joint > shoulder > hip > sternoclavicular joint > ankle > elbow Site: organism localized in synovial membrane serosanguinous sterile joint effusion
Brucellar destructive arthritis (9%)
indistinguishable from tuberculous / pyogenic arthritis
Brucellar osteomyelitis (2%)
pain, tenderness, swelling
Brucellar myositis (2%)
Dx: | serologic tests (enzyme-linked immunosorbent assay, counterimmunoelectrophoresis, rose bengal plate test |
Rx: | combination of aminoglycosides + tetracyclines |
DDx: | fibrous dysplasia, benign tumor, osteoid osteoma |
Caisson Disease
= DECOMPRESSION SICKNESS = THE BENDS
Etiology: | during too rapid decompression = reduction of surrounding pressure (ascent from dive, exit from caisson / hyperbaric chamber, ascent to altitude) nitrogen bubbles form (nitrogen more soluble in fat of panniculus adiposus, spinal cord, brain, bones containing fatty marrow) |
the bends = local pain in knee, elbow, shoulder, hip neurologic symptoms (paresthesia, major cerebral / spinal involvement)
chokes = substernal discomfort + coughing (embolization of pulmonary vessels)
Location: mostly in long tubular bones of lower extremity (distal end of shaft + epiphyseal portion); symmetrical lesions early: area of rarefaction healing phase: irregular new-bone formation with greater density peripheral zone of calcification / ossification ischemic necrosis of articular surface with secondary osteoarthritis
P.55
Calcium Pyrophosphate Dihydrate Crystal Deposition Disease
= CPPD = PSEUDOGOUT = FAMILIAL CHONDROCALCINOSIS
Most common crystalline arthropathy Types: 1. Osteoarthritic form (35 60%) 2. Pseudogout = acute synovitis (10 20%)
3. Rheumatoid form (2 6%)
4. Pseudoneuropathic arthropathy (2%)
5. Asymptomatic with tophaceous pseudogout (common)
Associated with: hyperparathyroidism, hypothyroidism, hemochromatosis, hypomagnesemia Prevalence: widespread in older population; M:F = 3:2 calcium pyrophosphate crystals in synovial fluid + within leukocytes (characteristic weakly positive birefringent diffraction pattern)
acute / subacute / chronic joint inflammation
Location: (a) knee (especially meniscus + cartilage of patellofemoral joint) (b) wrist (triangular fibrocartilage in distal radioulnar joint bilaterally)
(c) pelvis (sacroiliac joint, symphysis)
(d) spine (annulus fibrosis of lumbar intervertebral disk; NEVER in nucleus pulposus as in ochronosis)
(e) shoulder (glenoid), hip (labrum), elbow, ankle, acromioclavicular joint
polyarticular chondrocalcinosis (in fibro- and hyaline cartilage) large subchondral cyst (HALLMARK) numerous intraarticular bodies (fragmentation of subchondral bone) involvement of tendons, bursae, pinnae of the ear N.B.: pyrophosphate arthropathy resembles osteoarthritis: joint space narrowing + extensive subchondral sclerosis @ Hand
Distribution: radiocarpal compartment; trapezioscaphoid joint + 1 CMC; 2,3 MCP joints; bilateral symmetric resembling degenerative joint disease (without DIP and PIP involvement) small hook-like osteophytes at radial aspect of metacarpal heads 2 & 3 extensive narrowing / obliteration of joint space between distal radius + scaphoid: incorporation of scaphoid into articular surface of radius prominent cysts
calcification of triangular fibrocartilage scapholunate separation destruction of trapezioscaphoid space
@ Knee
medial femorotibial + patellofemoral compartments commonly involved simultaneously (as in osteoarthritis) but with greater osseous destruction + fragmentation disproportionate narrowing of patellofemoral joint
@ Spine
chondrocalcinosis / calcifications of outer fibers of annulus fibrosus resembling syndesmophytes vertical radiodense line in symphysis pubis
Camptomelic Dysplasia
= sporadic / autosomal recessive dwarfism
Incidence: | 0.05:10,000 births |
Associated with:
Hydrocephalus (23%)
Congenital heart disease (30%): VSD, ASD, tetralogy, AS
Hydronephrosis (30%)
npretibial dimple
macrocephaly, cleft palate, micrognathia (90 99%) @ Chest & spine
hypoplastic scapulae (92%) narrow bell-shaped chest hypoplastic vertebral bodies + nonmineralized pedicles (especially lower cervical spine)
@ Pelvis
vertically narrowed iliac bones vertical inclination of ischii wide symphysis narrow iliac bones with small wings shallow acetabulum
@ Extremities (lower extremity more severely affected)
dislocation of hips + knees anterior bowing (= campto) of long bones: marked in tibia + moderate in femur hypoplastic fibula small secondary ossification center of knee small primary ossification center of talus clubfoot
OB-US:
bowing of tibia + femur decreased thoracic circumference hypoplastic scapulae cleft palate
Prognosis: | death usually <5 months of age (within first year in 97%) due to respiratory insufficiency |
Carpal Tunnel Syndrome
= entrapment syndrome caused by chronic pressure on the median nerve within the carpal tunnel
Cause: | repetitive wrist / finger flexion; carpal tunnel crowding by cyst / mass / flexor tendon tendinitis or tenosynovitis / anomalous origin of lumbrical muscles |
Pathogenesis: | probably ischemia with venous congestion (stage 1), nerve edema from anoxic damage to capillary endothelium (stage 2), impairment of venous + arterial blood supply (stage 3) |
P.56
nocturnal hand discomfort
weakness, clumsiness, finger paresthesias
MR:
pseudoneuroma of median nerve = swelling of median nerve proximal to carpal tunnel swelling of nerve within carpal tunnel increased signal intensity of nerve on T2WI volar bowing of flexor retinaculum swelling of tendon sheath (due to tenosynovitis) mass(es) within carpal tunnel marked enhancement (nerve edema = breakdown of blood-nerve barrier) no enhancement (ischemia) provoked by wrist held in an extended / flexed position
Carpenter Syndrome
= ACROCEPHALOPOLYSYNDACTYLY type 2
autosomal recessive
retardation
hypogonadism
patent ductus arteriosus acro(oxy)cephaly preaxial polysyndactyly + soft-tissue syndactyly
Cerebrocostomandibular Syndrome
= rare bone disorder of uncertain transmission
respiratory distress (due to flail chest + airway abnormalities)
11 pairs of ribs: abnormal costovertebral articulations posterior ossification gaps resembling fractures
microcephaly micrognathia congenital heart disease DDx: multiple fractures
Chondroblastoma
= CODMAN TUMOR = BENIGN CHONDROBLASTOMA = CARTILAGE-CONTAINING GIANT CELL TUMOR
Incidence: | 1% of primary bone neoplasms (700 cases in world literature) |
Age: | peak in 2nd decade (range of 8 59 years); 10 26 years (90%); M:F = 2:1; occurs before cessation of enchondral bone growth |
Path: | derived from primitive cartilage cells |
Histo: | polyhedral chondroblasts + multinucleated giant cells + nodules of pink amorphous material (= chondroid) = epiphyseal chondromatous giant cell tumor (resembles chondromyxoid fibroma); chicken wire calcification = pericellular deposition of calcification is virtually PATHOGNOMONIC |
symptomatic for months to years prior to treatment
mild joint pain, tenderness, swelling (joint effusion)
limitation of motion
Location:
long bones (80%): proximal femur + greater trochanter (23%), distal femur (20%), proximal tibia (17%), proximal humerus (17%)
2/3 in lower extremity, 50% about knee may occur in apophyses (minor + greater trochanter, patella, greater tuberosity of humerus)
flat bones: near triradiate cartilage of innominate bone, rib (3%)
short tubular bones of hand + feet
Site: | eccentric medullary, subarticular location with open growth plate (98% begin within epiphysis); tumor growth may continue to involve metaphysis (50%) + rarely diaphysis |
oval / round eccentrically placed lytic lesion of epiphysis 1 4 cm in diameter occupying < one-half of epiphysis well-defined sclerotic margin, lobulated in 50% stippled / irregular calcifications in 25 30 50% (cartilaginous clumps better visualized by CT) intact scalloped cortical border thick periosteal reaction in metaphysis (50%) / joint involvement periostitis of adjacent metaphysis / diaphysis (30 50%) open growth plate in majority of patients
MR:
MR tends to overestimate extent + aggressiveness due to large area of reactive edema! intermediate to low signal intensity on T2WI relative to fat extensive intramedullary signal abnormalities consistent with bone marrow edema peripheral rim of very low signal intensity hypointense changes on T1WI + hyperintense on T2WI in adjacent soft tissues (muscle edema) in 50% joint effusion
Prognosis: | almost always benign; may become locally aggressive; rarely metastasizes |
Dx: | surgical biopsy |
Rx: | curettage + bone chip grafting (recurrence in 25%) |
DDx: | (1) Ischemic necrosis of femoral head (may be indistinguishable, more irregular configuration) (2) Giant cell tumor (usually larger + less well demarcated, not calcified, older age group with closed growth plate) (3) Chondromyxoid fibroma (4) Enchondroma (5) Osteomyelitis (less well-defined, variable margins) (6) Aneurysmal bone cyst (7) Intraosseous ganglion (8) Langerhans cell histiocytosis (less well-defined, variable margins) (9) Primary bone sarcoma |
Chondrodysplasia Punctata
= CONGENITAL STIPPLED EPIPHYSES = DYSPLASIA EPIPHYSEALIS PUNCTATA = CHONDRODYSTROPHIA CALCIFICANS CONGENITA
= proportional / mesomelic dwarfism
Etiology: peroxisomal disorder characterized by fibroblast plasmalogen deficiency Incidence: 1:110,000 births
AUTOSOMAL RECESSIVE CHONDRODYSPLASIA PUNCTATA = RHIZOMELIC TYPE
Associated with: CHD (common) flat face
congenital cataracts
ichthyotic skin thickening
mental retardation
cleft palate
multiple small punctate calcifications of varying size in epiphyses (knee, hip, shoulder, wrist), in base of skull, in posterior elements of vertebrae, in respiratory cartilage and soft tissues (neck, rib ends) before appearance of ossification centers prominent symmetrical shortening of femur + humerus (rarely all limbs symmetrically affected) congenital dislocation of hip flexion contractures of extremities clubfeet metaphyseal splaying of proximal tubular bones (in particular about knee) thickening of diaphyses prominent vertebral + paravertebral calcifications coronal clefts in vertebral bodies Prognosis: death usually <1 year of age DDx: Zellweger syndrome
P.57
CONRADI-H NERMANN DISEASE
= NONRHIZOMELIC TYPE
more common milder nonlethal variety;
autosomal dominant
normal intelligence
more widespread but milder involvement as above Prognosis: survival often into adulthood
Cx: | respiratory failure (severe underdevelopment of ribs), tracheal stenosis, spinal cord compression |
DDx: | (1) Cretinism (may show epiphyseal fragmentation, much larger calcifications within epiphysis) (2) Warfarin embryopathy (3) Zellweger syndrome |
Chondroectodermal Dysplasia
= ELLIS-VAN CREVELD SYNDROME = MESODERMAL DYSPLASIA
= autosomal recessive acromesomelic dwarfism
Incidence: 120 cases; in inbred Amish communities Associated with: congenital heart disease in 50% (single atrium, ASD, VSD) ectodermal dysplasia:
absent / hypoplastic brittle spoon-shaped nails
irregular + pointed dysplastic teeth, partial anodontia, teeth may be present at birth
scant / fine hair
obliteration of maxillary mucobuccal space (thick frenula between alveolar mucosa + upper lip)
strabismus
genital malformations: epispadia, hypospadia, hypoplastic external genitalia, undescended testicles
hepatosplenomegaly accelerated skeletal maturation normal spine @ Skull
wormian bones cleft lip
@ Chest
elongated narrow thorax in AP + transverse dimensions exaggerating the heart size cardiomegaly (frequently ASD / single atrium) short horizontal ribs + anterior osseous expansion elevated clavicles
@ Pelvis
small flattened ilium trident shape of acetabulum with indentation in roof + bony spur (almost pathognomonic) acetabular + tibial exostoses
@ Extremities
variety of micromelia (= thickening + shortening of all long bones): acromelia = hypoplasia / absence of terminal phalanges mesomelia = shortening of forearms + lower legs (radius + tibia > humerus + femur)
cone-shaped epiphyses premature ossification of proximal humeral + femoral epiphyses @ Upper extremity
drumstick forearm = swelling of proximal end of ulna + distal end of radius anterior dislocation of radial head (due to shortening of ulna) carpal / tarsal fusion = frequent fusion of two / more carpal (hamate + capitate) + tarsal bones (after complete ossification) supernumerary carpal bones postaxial polydactyly common (usually finger, rarely toe) syndactyly of hands + feet
@ Lower extremity
genu valgum: slanting of proximal tibial metaphysis (= delayed development of tibial plateau) excessive shortening of fibula
widening of proximal tibial shaft medial tibial diaphyseal exostosis
OB-US:
proportional shortening of long bones small thorax with decreased circumference increased cardiothoracic ratio ASD polydactyly
Prognosis: death within first month of life in 33 50% (due to respiratory / cardiac complications) DDx: asphyxiating thoracic dysplasia (difficult distinction); rhizomelic achondroplasia
Chondromalacia Patellae
= pathologic softening of patellar cartilage leading to defects of surface (chondrosis) / osteoarthritis
Cause: trauma, tracking abnormality of patella anterior knee pain
asymptomatic (incidental arthroscopic diagnosis)
Chondromyxoid Fibroma
Rare benign cartilaginous tumor; initially arising in cortex
Incidence: | <1% of all bone tumors |
Histo: | chondroid + fibrous + myxoid tissue (related to chondroblastoma); may be mistaken for chondrosarcoma |
Age: | peak 2nd 3rd decade (range of 5 79 years); M:F = 1:1 |
slowly progressive local pain, swelling, restriction of motion P.58
Classification of Chondromalacia Patellae
Grade Arthroscopic Pathology T1WI of MRI 1 softening + swelling of articular cartilage (chondrosis) focal hypointense areas not extending to cartilage surface / subchondral bone (MR / MR arthrography unreliable) 2 blistering of articular cartilage producing deformity of surface <1 cm in diameter focal hypointense areas extending to cartilage surface with preservation of sharp cartilage margins 3 surface irregularity + cartilage fibrillation with minimal extension to subchondral bone >1 cm in diameter focal hypointense areas extending to articular surface but not to osseous surface; loss of sharp dark margin between articular cartilage of patella + trochlea 4 ulceration with exposure of subchondral bone focal hypointense areas extending from subchondral bone to cartilage surface; cartilage thinned to subchondral bone Location: (a) long bones (60%): about knee (50%), proximal tibia (82% of tibial lesions), distal femur (71% of femoral lesions), fibula (b) short tubular bones of hand + feet (20%)
(c) flat bones: pelvis, ribs (classic but uncommon)
Site: eccentric, metaphyseal (47 53%), metadiaphyseal (20 43%), metaepiphyseal (26%), diaphyseal (1 10%), epiphyseal (3%) expansile ovoid lesion with radiolucent center + oval shape at each end of lesion long axis parallel to long axis of host bone (1 10 cm in length and 4 7 cm in width) geographic bone destruction (100%) well-defined sclerotic margin (86%) expanded shell = bulged + thinned overlying cortex (68%) partial cortical erosion (68%) scalloped margin (58%) septations (57%) may mimic trabeculations stippled calcifications within tumor in advanced lesions (7%) NO periosteal reaction (unless fractured) Prognosis: 25% recurrence rate following curettage Cx: malignant degeneration distinctly unusual DDx: (1) Aneurysmal bone cyst (2) Simple bone cyst
(3) Nonossifying fibroma
(4) Fibrous dysplasia
(5) Enchondroma
(6) Chondroblastoma
(7) Eosinophilic granuloma
(8) Fibrous cortical defect
(9) Giant cell tumor
Chondrosarcoma
PRIMARY CHONDROSARCOMA
no preexisting bone lesion
SECONDARY CHONDROSARCOMA
as a complication of a preexisting skeletal abnormality such as
Osteochondroma
Enchondroma
Parosteal chondroma
Spread: | via marrow cavity / periosteum |
Metastases (uncommon) to: | lung, epidural space |
CT:
chondroid matrix mineralization of rings and arcs (CHARACTERISTIC) in 70% nonmineralized portion of tumor hypodense to muscle (high water content of hyaline cartilage) extension into soft-tissues
MR:
low to intermediate signal intensity on T1WI high signal intensity on T2WI + hypointense areas (due to mineralization / fibrous septa) enhancement of fibrous septations
Central Chondrosarcoma
= INTRAMEDULLARY CHONDROSARCOMA = ENDOSTEAL CHONDROSARCOMA
Incidence: 3rd most common primary bone tumor (1st multiple myeloma, 2nd osteosarcoma); 8 17% of biopsied primary bone tumors Path: lobular morphology with variable amounts of calcium; presence of fibrous bands at tumor-marrow interface suggests malignancy (DDx from atypical enchondroma) Histo: arises from chondroblasts (tumor osteoid is never formed) Age: median 45 years; 50% >40 years; 10% in children (rapidly fatal); M:F = 2:1 hyperglycemia as paraneoplastic syndrome (85%)
Location: neck of femur, pubic rami, proximal humerus, ribs (19%), skull (sphenoid bone, cerebellopontine angle, mandible), sternum, spine (3 12%) Site: central within medullary canal + meta- / diaphysis expansile osteolytic lesion 1 to several cm in size short transition zone sclerotic margin (well defined from host bone) small irregular punctate / snowflake type of calcification; single / multiple late: loss of definition + break through cortex endosteal cortical thickening, sometimes at a distance from the tumor (due to invasion of haversian system) presence of large soft-tissue mass DDx: benign enchondroma, osteochondroma, osteosarcoma, fibrosarcoma
Peripheral Chondrosarcoma
= EXOSTOTIC CHONDROSARCOMA
= malignant degeneration of hereditary multiple osteochondromatosis and rarely of a solitary exostosis (beginning in cartilaginous cap of exostosis)
P.59
Frequency: 8% of all chondrosarcomas Average age: 50 55 years for solitary exostosis; 25 30 years for hereditary multiple osteochondromatosis; M:F = 1.5:1 Histo: low histologic grade in 67 85% growth after skeletal maturity
gradually increasing pain, often worse at night
local swelling / palpable mass (45%)
Location: pelvis, hip, scapula, sternum, ribs, ends of humerus / femur, skull, facial bones growth of a previously unchanged osteochondroma in a skeletally mature patient unusually large soft-tissue mass (= hyaline cartilage cap) containing flocculent / streaky chondroid calcifications (CHARACTERISTIC): cartilage cap 1.5 12 cm (average, 5.5 6 cm) thick >1.5 cm is suspect of malignant transformation
irregular / indistinct lesion surface: dense radiopaque center with streaks radiating to periphery with loss of smooth margin
focal regions of radiolucency in interior of lesion erosion / destruction of adjacent bone Metastases: in 3 7%, most commonly to lung Rx: wide resection Prognosis: 70 90% long-term survival DDx: (1) Osteochondroma (densely calcified with multiple punctate calcifications) (2) Parosteal osteosarcoma (more homogeneous density of calcified osteoid)
Clear Cell Chondrosarcoma
Usually mistaken for chondroblastoma because of low grade malignancy (may be related)!
Histo: | small lobules of tissue composed of cells with centrally filled vesicular nuclei surrounded by large clear cytoplasm |
Age: | 19 68 years, predominantly after epiphyseal fusion |
Location: | proximal femur, proximal humerus, proximal ulna, lamina vertebrae (5%); pubic ramus |
Site: | epiphysis |
Enchondroma versus Chondrosarcoma in Appendicular Skeleton
Enchondroma | Intramedullary Chondrosarcoma | |
---|---|---|
Mean age and sex | 40 years; M:F = 2:3 | 50 years; M:F = 11:9 |
Palpable mass | 28% | 82% |
Pain | 40% (fracture associated) | 95% (longer duration + increasing severity) |
Lesion location | hands, feet | axial skeleton (spine, pelvis) |
Site | diaphysis | metaphysis, epiphysis |
Lesion size | <5 cm | >5 6 cm |
Endosteal scalloping | ||
relative to cortical thickness | 90% <2/3 of cortical thickness | 90% >2/3 of cortical thickness, |
relative to lesion length | 66% along <2/3 of lesion | 79% along >2/3 of lesion |
Cortical remodeling (radiography) | 15% | 47% |
Cortical thickening (radiography) | 17% | 47% |
Periosteal reaction (radiography) | 3% | 47% |
Pathologic fracture (radiography) | 5% | 27% |
Matrix mineralization (CT) | 100% (more extensive) | 94% (less extensive) |
Cortical destruction (CT) | 8% | 88% |
Soft-tissue extension (MR) | 3% | 76% |
Small hyperintense foci (T1WI) | 65% | 35% |
single lobulated oval / round sharply marginated lesion of 1 2 cm in size surrounding increased bone density aggressive rapid growth over 3 cm may contain calcifications bone often enlarged indistinguishable from conventional chondrosarcoma / chondroblastoma (slow growth over years)
Extraskeletal Chondrosarcoma
Incidence: | 2% of all soft-tissue sarcomas |
Myxoid Extraskeletal Chondrosarcoma
(most common)
Mean age: | 50 years (range 4 92 years); M > F |
Histo: | surrounded by fibrous capsule + divided into multiple lobules by fibrous septa; delicate strands of small elongated chondroblasts are suspended in an abundant myxoid matrix; foci of mature hyaline cartilage are rare |
slowly growing soft-tissue mass
pain + tenderness (33%)
Metastatic in 40 45% at time of presentation! Location: extremities (thigh most common) Site: deep soft tissues; subcutis (25%) lobulated soft-tissue mass WITHOUT calcification / ossification usually between 4 and 7 cm in diameter
MR:
approximately equal to muscle on T1WI + equal to fat on T2WI may mimic a cyst / myxoma
P.60
Prognosis: | 45% 10-year survival rate; 5 15 years survival after development of metastases |
Extraskeletal Mesenchymal Chondrosarcoma
50% of all mesenchymal chondrosarcomas arise in soft tissues Histo: proliferation of small primitive mesenchymal cells with scattered islands of cartilage; hemangiopericytoma-like vascular pattern Bimodal age distribution: M = F tumors of head + neck in 3rd decade (common): meninges, periorbital region
tumors of thigh + trunk in 5th decade
frequently metastasized to lungs + lymph nodes
matrix mineralization (50 100%) characterized as rings + arcs / flocculent + stippled calcification / dense mineralization
MR:
approximately equal to muscle on T1WI + equal to fat on T2WI signal voids from calcifications homogeneous enhancement
Prognosis: | 25% 10-year survival rate |
Cleidocranial Dysostosis
= CLEIDOCRANIAL DYSPLASIA = MUTATIONAL DYSOSTOSIS
= delayed ossification of midline structures (particularly of membranous bone)
Autosomal dominant disease
@ Skull
large head
diminished / absent ossification of skull (in early infancy) wormian bones widened fontanels + sutures with delayed closure persistent metopic suture brachycephaly + prominent bossing large mandible high narrow palate ( cleft) hypoplastic paranasal sinuses delayed / defective dentition
@ Chest
hypoplasia / absence (10%) of clavicles (defective development usually of lateral portion, R > L (DDx: congenital pseudarthrosis of clavicle) thorax may be narrowed + bell-shaped supernumerary ribs incompletely ossified sternum hemivertebrae, spondylosis (frequent)
@ Pelvis
delayed ossification of bones forming symphysis pubis (DDx: bladder exstrophy) hypoplastic iliac bones
@ Extremities
radius short / absent elongated second metacarpals pseudoepiphyses of metacarpal bases short hypoplastic distal phalanges of hand pointed terminal tufts coned epiphyses coxa vara = deformed / absent femoral necks accessory epiphyses in hands + feet (common)
OB-US:
cephalopelvic disproportion (large fetal head + narrow birth canal of affected maternal pelvis) necessitates cesarean section
Coccidioidomycosis
Histo: | chronic granulomatous process in bones, joints, periarticular structures |
Location: | (a) bones: most frequently in metaphyses of long bones + medial end of clavicle, spine, ribs, pelvis / bony prominences of patella, tibial tuberosity, calcaneus, olecranon, acromion (b) weight-bearing joints (33%): ankle, knee, wrist, elbow desert rheumatism = immune-complex mediated arthritis (c) tenosynovitis of hand, bursitis |
focal areas of destruction, formation of cavities (early) = bubbly bone lesion bone sclerosis surrounding osteolysis (later, rare) proliferation of overlying periosteum destruction of vertebra with preservation of disk space psoas abscess indistinguishable from tuberculosis, may calcify joints rarely infected (usually monoarticular from direct extension of osteomyelitic focus): synovial effusion, osteopenia, joint space narrowing, bone destruction, ankylosis soft-tissue abscesses common DDx: tuberculosis
Congenital Insensitivity to Pain With Anhydrosis
= rare autosomal recessive disorder presumably on the basis of abnormal neural crest development
Age: presenting at birth Incidence: 15 reported cases Path: absence of dorsal + sympathetic ganglia, deficiency of neural fibers <6 m in diameter + disproportionate number of fibers of 6 10 m in diameter history of painless injuries + burns (DDx: familial dysautonomia, congenital sensory neuropathy, hereditary sensory radicular neuropathy, acquired sensory neuropathy, syringomyelia)
abnormal pain + temperature perception
burns, bruises, infections are common
biting injuries of fingers, lips, tongue
absence of sweating
mental retardation
CRITERIA: (1) defect must be present at birth (2) general insensitivity to pain
(3) general mental / physical retardation
epiphyseal separation in infancy (epiphyseal injuries result in growth problems) metaphyseal fractures in early childhood diaphyseal fractures in late childhood Charcot joints = neurotrophic joints (usually weight-bearing joints) with effusions + synovial thickening ligamentous laxity bizarre deformities + gross displacement + considerable hemorrhage (unnoticed fractures + dislocations) osteomyelitis + septic arthritis may occur + progress extensively DDx: (1) sensory neuropathies (eg, diabetes mellitus) (2) hysteria
(3) syphilis
(4) mental deficiency,
(5) syringomyelia
(6) organic brain disease
P.61
Cornelia De Lange Syndrome
= AMSTERDAM DWARFISM
mental retardation (IQ <50)
hirsutism; hypoplastic genitalia
feeble growling cry
high forehead; short neck
arched palate
bushy eyebrows meeting in midline + long curved eyelashes
small nose with depressed bridge; upward tilted nostrils; excessive distance between nose + upper lip
small + brachycephalic skull hypoplasia of long bones (upper extremity more involved) forearm bones may be absent short radius + elbow dislocation thumbs placed proximally (hypoplastic 1st metacarpal) short phalanges + clinodactyly of 5th finger
Cortical Desmoid
= AVULSIVE CORTICAL IRREGULARITY = PERIOSTEAL / SUBPERIOSTEAL DESMOID = SUBPERIOSTEAL / CORTICAL ABRASION = SUBPERIOSTEAL CORTICAL DEFECT
= rare fibrous lesion of the periosteum
Age: peak 14 16 years (range of 3 17 years); M:F = 3:1 Histo: shallow defect filled with proliferating fibroblasts, multiple small fragments of resorbing bone (microavulsions) at tendinous insertions no localizing signs / symptoms
Location: posteromedial aspect of medial femoral epicondyle along medial ridge of linea aspera at attachment of adductor magnus aponeurosis; 1/3 bilateral area of cortical thickening 1 2 cm irregular, shallow, concave saucerlike crater with sharp margin lamellated periosteal reaction localized cortical hyperostosis proximally (healing phase) May be confused with a malignant tumor (eg, osteosarcoma) / osteomyelitis!
Cri-Du-Chat Syndrome
= deletion of short arm of 5th chromosome (5 p)
generalized dwarfism due to marked growth retardation
failure to thrive
peculiar high-pitched cat cry (hypoplastic larynx)
antimongoloid palpebral fissures
strabismus
profound mental retardation
round facies
low-set ears
Associated with: congenital heart disease (obtain CXR!) agenesis of corpus callosum microcephaly hypertelorism small mandible faulty long-bone development short 3rd, 4th, 5th metacarpals long 2nd, 3rd, 4th, 5th proximal phalanges horseshoe kidney Dx: made clinically
Crouzon Syndrome
= CRANIOFACIAL SYNOSTOSIS / DYSOSTOSIS
= Apert syndrome without syndactyly
= skull + cranial base deformities characterized by craniosynostosis, maxillary hypoplasia, shallow orbits, ocular proptosis, bifid uvula, cleft palate
Prevalence: 1:25,000 Etiology: autosomal dominant inheritance (in 67%) Associated intracranial anomalies: anomalous venous drainage, hydrocephalus (often progressive), Chiari I malformation (71%) parrot-beak nose
strabismus
deafness
mental retardation
dental abnormalities
bifid uvula
acanthosis nigrans (= hyperpigmented hyperkeratotic lesions on neck + near joint flexures)
premature craniosynostosis: acro(oxy)cephaly / brachycephaly / scaphocephaly / trigonocephaly / cloverleaf skull hypertelorism + exophthalmos (due to shallow orbits) hypoplastic maxilla (relative prominence of mandible) cleft palate calcification of stylohyoid ligament (in 50% of patients >4 years of age) C2 to C5 spine abnormalities (in up to 40%) elbow malformation (18%) minor hand deformities (10%) visceral anomalies (7%) musculoskeletal deformities (7%)
OB-US:
cloverleaf appearance (coronal view) + bilateral frontal indentations (axial view) of skull increased interorbital distance + ocular proptosis mild ventriculomegaly
Cruciate Ligament Injury
COMPLETE TEAR
failure to identify ligament amorphous areas of high signal intensity on T1WI + T2WI with inability to define ligamentous fibers focal discrete complete disruption of all visible fibers
PARTIAL / INTRASUBSTANCE TEAR
abnormal signal intensity within substance of ligament with some intact + some discontinuous fibers
Anterior Cruciate Ligament Injury (ACL tear)
Frequency: | in up to 69% of all patients undergoing arthroscopy; in up to 72% of acutely injured knees with hemarthrosis |
Mechanism: | twisting, valgus impaction + internal rotation, hyperextension of knee with foot planted (football) / lower leg forcibly externally rotated during knee flexion (backwards fall while skiing) |
pivot shift test (82 90% sensitive) = examiner applies valgus stress on internally rotated leg while flexing the knee; induced anterolateral rotary subluxation reduces spontaneously at 40 flexion with an audible pop
anterior drawer sign (22 80% sensitive) = proximal tibia displaces anteriorly with the knee flexed at 60 90
Lachman test (77 99% sensitive) = same as anterior drawer sign with knee flexed at 10 20
Location: midsubstance of ligament / near femoral attachment (in adults) / avulsion of anterior intercondylar eminence or tibial spines (in children) If the ACL appears intact in one of the sagittal oblique sequences discordant findings in other sequences can be disregarded! Site: intrasubstance tear near insertion of femoral condyle (frequently); bone avulsion (rarely) loss of fiber continuity + abnormal fiber orientation on PD image hyperintense signal (= focal fluid collection / soft-tissue edema) replacing the tendon substance in acute tear on T2WI pseudomass (hematoma + torn fibers) in intercondylar notch near femoral attachment concavity of anterior margin of ligament nondisplaced avulsion fracture of tibial eminence in children (coronal T1WI)
Secondary signs (low sensitivity, high specificity):
anterior translation of tibia (= anterior drawer sign) by >5 mm with respect to femur measured at midsagittal plane of lateral femoral condyle uncovering of lateral meniscus = posterior displacement of posterior horn of lateral meniscus >3.5 mm behind tibial plateau bowed PCL due to increased laxity = angle between proximal + distal limbs of PCL <105
Associated signs:
for anterolateral rotary instability (football, skiing):
bone bruise in lateral compartment (posterolateral tibia + terminal sulcus of lateral femoral condyle) in 40 90% on fat-suppressed T2WI ACL intact in 28% of adolescents with bone bruise
low-signal intensity line surrounded by region of high-signal intensity marrow edema in posterior aspect of lateral tibial plateau (= occult fracture) on STIR image
for hyperextension injury:
bone contusion in anterior tibial plateau + femoral condyles
varus stress with external rotation:
avulsion of joint capsule from lateral tibial rim (Segond fracture)
deepening of lateral femoral sulcus >1.5 mm (due to osteochondral impaction injury)
False-positive Dx:
slice thickness / interslice gap too great
adjacent fluid / synovial proliferation
cruciate ganglion / synovial cyst
Associated injuries:
meniscal tear (lateral > medial) in 65%
Rx: | (1) conservative: strengthening of quadriceps muscle + brace for activities (2) arthroscopic reconstruction with autograft (patellar tendon / combined semitendinosus and gracilis tendon) or allograft (cadaveric patellar / Achilles tendon) |
Subacute ACL Tear
Definition: | few weeks after injury |
fibers better defined as hemorrhage + edema subside change in fiber contour + angle of residual fragments
Chronic ACL Tear
Definition: | months to years after injury |
bridging fibrous scar within intercondylar notch (simulating an intact ligament with its low signal intensity) disorganized scar tissue instead of linear parallel fibers major distal ACL fragment assumes a more horizontal orientation (= less steep than the roof of the intercondylar notch or Blumensaat line) ACL may fuse to posterior cruciate ligament complete absence of ligament
Partial ACL Tear (15%)
Extremely difficult to diagnose! 40 50% of partial tears are missed on MR! positive Lachman test (in 12 30%)
MR primary signs positive for injury (in 33 43%)
Posterior Cruciate Ligament Injury (PCL)
Prevalence: | 2 23% of all knee injuries |
midsubstance of PCL most frequently involved (best seen on sagittal images) bone avulsion from posterior tibial insertion (<10%), best seen on lateral plain film
Mechanism:
Direct blow to proximal anterior tibia with knee flexed (dashboard injury)
midsubstance PCL tear injury to posterior joint capsule bone contusion at anterior tibial plateau + femoral condyles farther posteriorly
Hyperextension of knee
avulsion of tibial attachment of PCL (with preservation of PCL substance) ACL rupture bone contusion in anterior tibial plateau + anterior aspect of femoral condyles
Severe ab- / adduction + rotational forces
+ injury to collateral ligaments
Associated with: coexistent ligamentous injury in 70% anterior cruciate ligament 27 38% medial collateral ligament 20 23% lateral collateral ligament 6 7% medial meniscal tear 32 35% lateral meniscal tear 28 30% bone marrow injury 35 36% effusion 64 65%
In 30% of cases injury of PCL is isolated! posterior tibial laxity
difficult to evaluate arthroscopically unless ACL torn
Deep Fibromatosis
Aggressive Infantile Fibromatosis
= childhood equivalent of deep fibromatosis
Age: first 2 years of life; rarely >5 years of age; M > F Histo: may mimic infantile fibrosarcoma firm nodular soft-tissue mass within skeletal muscle / fascia / periosteum
Location: | head, neck (tongue, mandible, mastoid), shoulder, thigh, foot |
Extraabdominal Desmoid Tumor
= AGGRESSIVE FIBROMATOSIS = DEEP FIBROMATOSIS = MUSCULOAPONEUROTIC FIBROMATOSIS
= common benign aggressively growing soft-tissue tumor arising from connective tissue of muscle, fascia, aponeurosis outside abdominal cavity
Peak age: | 25 35 years |
Histo: | parallel halo arrays of uniform-appearing fibroblasts surrounded by highly variable amounts of collagen fibers with infiltrative growth pattern |
painless soft-tissue mass
Location: extremities (70%); shoulder (20%), chest wall + back (15%), thigh (12%), mesentery (10%), neck (10%), knee (7%); solitary (majority) / synchronous multicentricity in same extremity (10 15%) Most common benign soft-tissue tumor of the foot Site: fascia in / around muscle mostly <10 cm in diameter @ Bone
Erlenmeyer flask deformity in multicentric fibromatosis (infrequent)
@ Abdominal wall
Prevalence: in 87% in females of childbearing age Predilection: female patients taking birth control pills / during or after pregnancy Location: aponeurosis of rectus abdominis, internal oblique muscle
MR:
poorly defined (with invasion of fat / muscle) / lobulated well-defined lesion hypo- / isointense to muscle on T1WI hyperintense (hypercellular) / hyperintense with areas of low intensity (intermixed with fibrous components) / hypointense (hypocellular) on T2WI
Cx: | compresses / engulfs adjacent structures |
Prognosis: | 75% recurrence within 2 years after surgical excision (up to 87% local recurrence in <30 years of age; 20% recurrence rate in >20 years of age) |
Abdominal Desmoid Tumor
= DESMOID TUMOR
= uncommon benign tumor of the subgroup of fibromatoses consisting of fibrous tissue with insidious growth [desmos, Greek = band / tendon]
Location: | mesentery (most common mesenteric primary), musculoaponeurosis of rectus, internal oblique muscle; occasionally external oblique muscle |
Age: | peak age in 3rd decade, 70% between 20 and 40 years of age; M:F = 1:3 |
Path: | poorly circumscribed coarsely trabeculated tumor resembling scar tissue, confined to musculature + overlying aponeurosis |
Histo: | elongated spindle-shaped cells of uniform appearance, septated by dense bands of collagen, infiltration of adjacent tissue (DDx: low-grade fibrosarcoma, reactive fibrosis) |
Associated with: | Gardner syndrome, multiple pregnancies, prior trauma |
firm slowly growing deep-seated mass
Size: | 5 20 cm in diameter |
MR:
hypointense to muscle on T1WI + variable intensity on T2WI
CT:
ill-defined / well-circumscribed mass usually higher attenuation than muscle enhancement retraction, angulation, distortion of small / large bowel with mesenteric infiltration
US:
sharply defined + smoothly marginated mass of low / medium / high echogenicity
Cx: | compression / displacement of bowel / ureter, intestinal perforation |
Prognosis: | locally aggressive growth; 25 65% recurrence rate |
Rx: | local resection + radiotherapy, antiestrogen therapy |
DDx: | (1) Malignant tumor: metastasis, fibrosarcoma, rhabdomyosarcoma, synoviosarcoma, liposarcoma, fibrous histiocytoma, lymphoma (2) Benign tumor: neurofibroma, neuroma, leiomyoma (3) Acute hematoma |
Infantile Myofibromatosis
= GENERALIZED HAMARTOMATOSIS = CONGENITAL MULTIPLE FIBROMATOSIS = MULTIPLE VASCULAR LEIOMYOMAS = DESMOFIBROMATOSIS
= rare disorder characterized by proliferation of fibroblasts
P.62
P.63
Cause: | unknown |
Frequency: | most common fibromatosis in childhood |
Age: | at birth (in 60%), <2 years (in 89%); M:F = 1.7:1 |
Path: | well-marginated soft-tissue lesion 0.5 3 cm in diameter with scarlike consistency infiltration of surrounding tissues |
Histo: | spindle-shaped cells in short bundles and fascicles in periphery of lesion with features of both smooth muscle + fibroblasts; hemangiopericytoma-like pattern in center with necrosis, hyalinization, calcification |
P.64
Solitary lesion (50 75%)
Location: dermis, subcutis, muscle (86%); head, neck, trunk, bone (9%), GI tract (4%) Prognosis: spontaneous regression in 100%; recurrence after surgical excision in 7 10% Multicentric disease (25 50%)
Location: skin (98%), subcutis (98%), muscle (98%), bone (57%), viscera (25 37%): lung (28%), heart (16%), GI tract (14%), pancreas (9%), liver (8%) Prognosis: related to extent + location of visceral lesions with cardiopulmonary + GI involvement as harbingers of poor prognosis (death in 75 80%); spontaneous regression (33%)
firm nodules in skin, subcutis, muscle
overlying scarring of skin with ulceration
@ Skeleton
Location: any bone may be involved; commonly in femur, tibia, rib, pelvis, vertebral bodies, calvarium; often symmetric Site: metaphysis of long bones eccentric lobulated lytic foci with smooth margins 0.5 1.0 cm in size well-defined with narrow zone of transition initially no sclerosis; sclerotic margin with healing osseous foci may increase in size and number healing leaves little residual abnormality unusual osseous findings: periosteal reaction, pathologic fracture vertebra plana, kyphoscoliosis with posterior scalloping of vertebral bodies
NUC (bone scan):
increased / little radiotracer uptake
DDx: (1) Langerhans cell histiocytosis (skin lesions) (2) Neurofibromatosis (multiple masses)
(3) Osseous hemangiomas / lymphangiomatosis / lipomatosis
(4) Metastatic neuroblastoma
(5) Multiple nonossifying fibromas
(6) Enchondromatosis
(7) Hematogenous osteomyelitis (unusual organism)
(8) Fibrous dysplasia
@ Soft tissue
solid mass with central necrosis central / peripheral solitary / multiple calcifications prominent vascularity of skin lesions resembles hemangiomas CT:
attenuation increased compared to muscle, before + after contrast enhancement
MR:
hypo- to hyperintense mass on T1WI + T2WI
DDx: (1) Neurofibromatosis (2) Infantile fibrosarcoma, leiomyosarcoma
(3) Angiomatosis
@ Lung
interstitial fibrosis, reticulonodular infiltrates discrete mass generalized bronchopneumonia
@ GI tract
diffuse narrowing / multiple small filling defects
Dermatomyositis
= autoimmune inflammatory myopathy with diffuse nonsuppurative inflammation of striated muscle + skin
Cause: | cell-mediated (type IV) autoimmune attack on striated muscle |
Pathophysiology: | damaged chondroitin sulfate no longer inhibits calcification |
Path: | atrophy of muscle bundles followed by edema and coagulation necrosis, fibrosis, calcification |
Histo: | mucoid degeneration with round cell infiltrates concentrated around blood vessels |
Age: | bimodal: 5 15 and 50 60 years; M:F = 1:2 |
gradual onset of muscle weakness
elevated muscle enzymes (creatinine kinase, aldolase)
myositis-specific autoantibodies: anti-Jo-1
anti-aminoacyl-tRNA synthetase
arthritis, Raynaud phenomenon, fever, fatigue
interstitial lung disease
Prognosis: requires prolonged treatment
anti-Mi-2 antibodies:
V-shaped chest rash (= shawl rash)
cuticular overgrowth
Prognosis: good response to medication
anti-signal recognition particle antibodies
abrupt onset myositis heart involvement
@ Skeletal musculature
Location: thigh (vastus lateralis + intermedius m. with relative sparing of rectus + biceps femoris m.) > pelvic girdle > upper extremity > neck flexors > pharyngeal muscles bilateral symmetric edema in pelvic + thigh muscles fatty infiltration + muscle atrophy (over months to years) sheetlike confluent calcifications in soft tissues of extremities (quadriceps, deltoid, calf muscles), elbows, knees, hands, abdominal wall, chest wall, axilla, inguinal region) in 75%
@ Skeleton
pointing + resorption of terminal tufts rheumatoid-like arthritis (rare) floppy-thumb sign Cx: flexion contractures; soft-tissue ulceration
@ Chest
respiratory muscle weakness
disseminated pulmonary infiltrates (reminiscent of scleroderma) diaphragmatic elevation with reduced lung volumes + basilar atelectasis interstitial fibrosis (5 30%), most severely at lung bases: fine reticular pattern progressing to coarse reticulonodular pattern + honeycombing
bronchiolitis obliterans organizing pneumonia diffuse alveolar damage HRCT:
predominantly linear abnormalities + ground-glass attenuation air-space consolidation in middle + lower lung zones with peribronchial + subpleural distribution P.65
Cx: aspiration pneumonia (most common finding due to pharyngeal muscle weakness)
@ Myocardium
changes similar to skeletal muscle
@ GI tract
progressive weakness of proximal striated muscle:
dysphagia
atony + dilatation of esophagus atony of small intestines + colon
Clinical forms:
ACUTE FORM = childhood-onset form
fever, joint pain, lymphadenopathy, splenomegaly, subcutaneous edema
more severe dermatomyositis Prognosis: death within a few months
CHRONIC FORM = adult-onset form
= insidious onset with periods of spontaneous remission and relapse
low-grade fever, muscular aches + pains, edema
muscle weakness (due to active inflammation, necrosis, muscle atrophy with fatty replacement, steroid-induced myopathy)
first symptom in 50% skin erythema: heliotrope rash (= dusky erythema of eyelids) with periorbital edema, Gottron sign (= scaly erythematous papules of knuckles, major joints and upper body)
first symptom in 25%
Cx: | increased prevalence of malignant neoplasms of breast, prostate, lung, ovary, GI tract, kidney |
Dx: | muscle biopsy (normal in up to 15%) |
Polymyositis
= involves skeletal muscle only
Age: 4th decade
Desmoplastic Fibroma
= INTRAOSSEOUS DESMOID TUMOR
= rare locally aggressive benign neoplasm of bone with borderline malignancy resembling soft-tissue desmoids / musculoaponeurotic fibromatosis
Incidence: | 107 cases in world literature |
Histo: | intracellular collagenous material in fibroblasts with small nuclei |
Age: | mean of 21 years (range 15 months to 75 years); in 90% <30 years; M:F = 1:1 |
slowly progressive pain + local tenderness palpable mass
Location: | mandible (26%), ilium (14%), >50% in long bones (femur [14%], humerus [11%], radius [9%], tibia [7%], clavicle), scapula, vertebra, calcaneus |
Site: | central meta- / diaphyseal (if growth plate open); may extend into epiphysis with subarticular location (if growth plate closed) |
geographic (96%) / moth-eaten (4%) bone destruction without matrix mineralization narrow (96%) / poorly defined (4%) zone of transition no marginal sclerosis (94%) residual columns of bone with pseudotrabeculae are CLASSIC (91%) bone expansion (89%); may grow to massive size (simulating aneurysmal bone cyst / metastatic renal cell carcinoma) breach of cortex + soft-tissue mass (29%)
Cx: | pathologic fracture (9%) |
Prognosis: | 52% rate of local recurrence |
Rx: | wide excision |
DDx: | (1) Giant cell tumor (round rather than oval, may extend into epiphysis + subchondral bone plate) (2) Fibrous dysplasia (occupies longer bone, contains mineralized matrix, often with sclerotic rim) (3) Aneurysmal bone cyst (eccentric blowout appearance rather than fusiform) (4) Chondromyxoid fibroma (eccentric with delicate marginal sclerosis + scalloped border) |
Developmental Dysplasia of Hip (DDH)
= CONGENITAL DYSPLASIA OF HIP
= deformity of acetabulum due to disrupted relationship between femoral head and acetabulum
Acetabular dysplasia (without femoral subluxation / dislocation) can be determined only by imaging!
Etiology:
Late intrauterine event (98%)
mechanical:
oligohydramnios (restricted space in utero)
firstborn (tight maternal musculature)
in 60% of patients with DDH
breech position (hip hyperflexion results in shortening of iliopsoas muscle; L:R = 4:1)
in 30 50% of patients with DDH only 2 4% of deliveries are breech
physiologic (females are more sensitive to):
maternal estrogen (not inactivated by immature fetal liver) blocks cross-linkage of collagen fibrils
pregnancy hormone relaxin
Teratologic (2%) due to a neuromuscular disorder (myelodysplasia, arthrogryposis) occurring during 12th 18th week GA
Postnatal onset (<1%)
Incidence: | 0.15% of neonates (Australia 1%, Netherlands 3.7%, Poland 3.9%, Israel 5.9%, Austria 6.6%, Norway 16.9%) |
Age: | most dislocations probably occur after birth; M:F = 1:4 1:8; Caucasians > Blacks |
Increased risk:
infants born in frank breech position (25%; risk of breech:vertex = 6 8:1)
congenital torticollis (10 20%)
skull-molding deformities; scoliosis; generalized joint laxity (Larsen syndrome, Ehlers-Danlos syndrome, Down syndrome [5%]); neuromuscular disorders (eg, myelodysplasia, spina bifida, sacral agenesis, arthrogryposis multiplex)
family history of DDH (6 20%): 6% risk for subsequent sibling of normal parents, 36% risk for subsequent sibling of one affected parent; 12% risk for patient's own children
foot deformities [metatarsus adductus, clubfoot (2%)
neonatal hyperextension of hips: swaddling of infants in hip extension / strapping to cradle board
P.66
Radiographic Lines of Hip Joint Position |
Anatomy: | acetabulum has a small bony component + a large cartilaginous component at birth; acetabulum highly susceptible for modeling within first 6 weeks of age + minimally susceptible >16 weeks of age |
Classification:
Normal hip
Lax = subluxable hip
subluxability up to 6 mm is normal in newborns (still under influence of maternal hormones); decreasing to 3 mm by 2nd day of life
Concentric dislocatable unstable hip
= joint laxity allowing nondisplaced femoral head to become subluxed / dislocated under stress
Incidence: 0.25 0.85% of all newborn infants (2/3 are firstborns) Barlow positive
slight increase in femoral anteversion mild marginal abnormalities in acetabular cartilage early labral eversion Prognosis: 60% will become stable after 1 week; 88% will become stable by age of 2 months
Decentered subluxed hip
= femoral head shallow in location
loss of femoral head sphericity increased femoral anteversion early labral inversion shallow acetabulum
Eccentric dislocated hip
= femoral head frankly displaced out of acetabulum
reducible = Ortolani positive
irreducible = Ortolani negative
accentuated flattening of femoral head shallow acetabulum limbus formation (= inward growth + hypertrophy of labrum)
hip click = usually result of joint capsule and tendon stretching + snapping (often confused with hip clunk )
Acetabular Sector angles (in normal right hip)
positive examination result (up to 3 months of age):
positive Ortolani reduction test = reduction of proximal femur into the acetabulum by progressive abduction of flexed hips and knees associated with audible clunk
positive Barlow dislocation test = displacement of proximal femur by progressive adduction with downward pressure (piston maneuver) on flexed hips and knees associated with audible clunk
warning signs on physical examination:
limited hip abduction on affected side
shortening of thigh on affected side:
asymmetric thigh / buttock creases
Allis sign = Galeazzi sign = affected knee is lower with knees bent in supine position
Trendelenburg test = visible drooping + shortening on dislocated side with child standing on both feet, then one foot
Location: | left:right:bilateral = 11:1:4 |
Radiologic lines:
Line of Hilgenreiner
= line connecting superolateral margins of triradiate cartilage
Acetabular angle / index
= slope of acetabular roof = angle that lies between Hilgenreiner's line and a line drawn from most superolateral ossified edge of acetabulum to superolateral margin of triradiate cartilage
Perkin's line
= vertical line to Hilgenreiner's line through the lateral rim of acetabulum
Shenton's curved line
= arc formed by inferior surface of superior pubic ramus (= top of obturator foramen) + medial surface of proximal femoral metaphysis to level of lesser trochanter
disruption of line (DDx: coxa valga)
Center-edge angle
= angle subtended by one line drawn from the acetabular edge to center of femoral head + second line perpendicular to line connecting centers of femoral heads
<25 suggests femoral head instability
AP pelvic radiograph: >6 8 weeks of age (von Rosen view = legs abducted 45 + thighs internally rotated)
Not reliable first 3 months of life! proximal + lateral migration of femoral neck: P.67
eccentric position of proximal femoral epiphysis (position estimated by a circle drawn with a diameter equivalent to width of femoral neck) interrupted discontinuous arc of Shenton's line line drawn along axis of femoral shaft will not pass through upper edge of acetabulum but intersect the anterior-superior iliac spine (during Barlow maneuver) apex of metaphysis lateral to edge of acetabulum femoral shaft above horizontal line drawn through the Y-synchondroses unilateral shortening of vertical distance from femoral ossific nucleus / femoral metaphysis to Hilgenreiner's line femoral ossific nucleus / medial beak of femoral metaphysis outside inner lower quadrant of coordinates established by Hilgenreiner's + Perkin's lines
acetabular dysplasia = shallow incompletely developed acetabulum: acetabular angle >30 strongly suggests dysplasia development of false acetabulum delayed ossification of femoral epiphysis (usually evident between 2nd and 8th month of life)
US (practical only up to 4 6 months of age):
Too sensitive during first 2 weeks of life! (1) static evaluation (popularized in Europe by Graf)
(2) dynamic evaluation (popularized in USA by Harcke)
@ Relationship of femoral head & acetabulum
femoral head position at rest in neutral position hip instability under motion + stress maneuvers dislocated (= eccentric) hip can be reduced (Ortolani positive): hypoechoic femoral head not centered over triradiate cartilage between pubis + ischium (on transverse view) increased amount of soft-tissue echoes ( pulvinar ) between femoral head and acetabulum cartilaginous acetabular labrum interposed between head and acetabulum (inverted labrum) posterior + superior dislocation of head against ilium
equator sign = <50% of femoral head lies medial to line drawn along iliac bone (on coronal view): >58% coverage is normal; 58% to 33% coverage is indeterminate; <33% coverage is abnormal
@ Femoral head
disparity in size of directly visualized unossified femoral head disparity in presence + size of ossific nucleus
@ Acetabulum
delayed ossification of acetabular corner wavy contour of bony acetabulum with only slight curvature abnormally acute alpha angle (= angle between straight lateral edge of ilium + bony acetabular margin) >60 in an infant is normal 55 60 can be normal <4 weeks of age <55 occurs in an immature acetabulum 4 6 interobserver variation!
Prognosis: | alpha-angle <50 at birth / 50 59 after 3 months indicates significant risk for dislocation without treatment; follow-up at 4-week intervals are recommended |
No Caption Available. |
P.68
CT:
sector angle = angle between line drawn from center of femoral head to acetabular rim + horizontal axis of pelvis (= reflection of acetabular support)
anterior acetabular sector angle <50 posterior acetabular sector angle <90
Cx: | (1) Avascular necrosis of femoral head (2) Intraarticular obstacle to reduction (a) pulvinar = fibrofatty tissue at apex of acetabulum (b) hypertrophy of ligamentum teres (c) labral hypertrophy / inversion (3) Extraarticular obstacle to reduction (iliopsoas tendon impingement on anterior joint capsule with infolding of joint capsule) |
Prognosis: | 78% of hips become spontaneously normal by 4th week + 90% by 9th week |
Rx: | (1) Flexion-abduction-external rotation brace (Pavlik harness) / splint / spica cast (2) Femoral varus osteotomy (3) Pelvic (Salter) / acetabular rotation (4) Increase in acetabular depth (Pemberton) (5) Medialization of femoral head (Chiari) |
Diastrophic Dysplasia
= DIASTROPHIC DWARFISM = EPIPHYSEAL DYSOSTOSIS
= autosomal recessive severe rhizomelic dwarfism secondary to generalized disorder of cartilage followed by fibrous scars + ossifications
diastrophic = twisted habitus
cauliflower ear = ear deformity from inflammation of pinna
laryngomalacia
lax + rigid joints with contractures
normal intellectual development
@ Axial skeleton
cleft palate (25%) cervical spina bifida occulta hypoplasia of odontoid severe progressive kyphoscoliosis of lumbar spine (not present at birth) narrowed interpedicular space in lumbar spine short + broad bony pelvis posterior tilt of sacrum
@ Extremities
severe micromelia (predominantly rhizomelic = humerus + femur shorter than distal long bones widened metaphysis flattened epiphysis (retardation of epiphyseal ossification) with invagination of ossification centers into distal ends of femora multiple joint flexion contractures (notably of major joints) dislocation of one / more large joints (hip, elbow), lateral dislocation of patella coxa vara (common) medially bowed metatarsals clubfoot = severe talipes equinovarus ulnar deviation of hands oval + hypoplastic 1st metacarpal bone + abducted proximally positioned thumb = hitchhiker's thumb (CHARACTERISTIC) bizarre carpal bones with supernumerary centers widely spaced fingers
OB-US:
proportionately shortened long bones hitchhiker thumb clubfeet joint contractures abnormal spinal curvature
Prognosis: | death in infancy (due to abnormal softening of tracheal cartilage) |
Diffuse Idiopathic Skeletal Hyperostosis
= DISH = FORESTIER DISEASE = ANKYLOSING HYPEROSTOSIS
= common ossifying diathesis characterized by bone proliferation at sites of tendinous + ligamentous attachment (enthesis)
Etiology:
may be caused by altered vitamin A metabolism (elevated plasma levels of unbound retinol)
long-term ingestion of retinoid derivatives for treatment of acne (eg, Accutane );
? hypertrophic variant of spondylosis deformans
Age: | >50 years; M:F = 3:1 |
pain, tenderness in extraspinal locations
restricted motion of vertebral column
hyperglycemia
positive HLA-B27 in 34%
increased incidence of hyperostosis frontalis interna @ Spine
Location: middle + lower thoracic > lower cervical > entire lumbar spine flowing ossification of at least 4 contiguous vertebral bodies: osteophytes located anteriorly + laterally on right side (not on left because of aorta) osteophytes largest at level of intervertebral disk radiolucency beneath deposited bone
disk spaces well preserved, no apophyseal ankylosis, no sacroiliitis
@ Pelvis
bridge across superior aspect of symphysis pubis ossification of iliolumbar + sacrotuberous + sacroiliac ligaments (high probability for presence of spinal DISH, DDx: fluorosis) whiskering at iliac crest, ischial tuberosity, trochanters broad osteophytes at lateral acetabular edge, inferior portions of sacroiliac joints
@ Extremities
big heel spurs (on plantar + posterior surface of calcaneus) spur of olecranon process of ulna spur on anterior surface of patella ossification of coracoclavicular ligament, patellar ligament, tibial tuberosity, interosseous membranes
Cx: | postoperative heterotopic bone formation (hip) |
DDx: | (1) Fluorosis (increased skeletal density) (2) Acromegaly (posterior scalloping, skull features) (3) Hypoparathyroidism (4) X-linked hypophosphatemic vitamin D resistant rickets
P.69 (5) Ankylosing spondylitis (squaring of vertebral bodies, coarser syndesmophytes, sacroiliitis, apophyseal alteration)(6) Intervertebral osteochondrosis (vacuum phenomenon, vertebral body marginal sclerosis, decreased intervertebral disk height) |
Dislocation
Hip Dislocation
Incidence: | 5% of all dislocations |
POSTERIOR HIP DISLOCATION (80 85%)
Mechanism: classical dashboard injury (= flexed knee strikes dashboard) Associated with: fractures of posterior rim of acetabulum, femoral head adducted lower extremity flexed at hip
ANTERIOR HIP DISLOCATION (5 10%)
Mechanism: forced abduction + external rotation Associated with: fractures of acetabular rim, greater trochanter, femoral neck, femoral head (characteristic depression on posterosuperior and lateral portion) anterior obturator dislocation
superoanterior / pubic hip dislocation
lower extremity in external rotation
prominent lesser trochanter obturator position of femoral head
CENTRAL ACETABULAR FRACTURE-DISLOCATION
Mechanism: force applied to lateral side of trochanter
Patellar Dislocation
= TRANSIENT LATERAL PATELLAR DISLOCATION
Incidence: | 2 3% of all knee injuries |
Mechanism: | during attempt to slow forward motion while pivoting medially on a planted foot; internal rotation of femur on fixed tibia while knee is flexed + quadriceps contraction produces a net lateral force |
At risk: | shallow trochlear groove |
Associated with: | medial meniscal tear / major ligamentous injury in 31% |
Age: | young physically active people |
hemarthrosis (most common cause of hemarthrosis in young conscripts)
swelling + tenderness of medial retinaculum
>50% not clinically diagnosed initially! increased signal intensity / thickening / disruption of medial patellar retinaculum lateral patellar tilt contusion / microfracture / osteochondral injury of nonarticular surface of lateral femoral condyle + medial articular surface of patella hemarthrosis
MR:
bone contusion of anterolateral aspect of lateral femoral condyle + inferomedial aspect of patella sprain / disruption / avulsion of medial retinaculum + medial patellofemoral ligament + medial patellotibial lig. Mr Imaging Signs of Patellar Dislocation
elevation of vastus medialis obliquus muscle
Rx: | (1)Temporary immobilization + rehabilitation: successful in 75% (2) Surgery: fixation of osteochondral fragments, medial capsule repair, lateral retinacular release, vastus medialis et lateralis rearrangement, medial retinaculum reefing |
Shoulder Dislocation
Sternoclavicular Dislocation (3%)
Acromioclavicular Dislocation (12%)
Grade 1 = | soft-tissue swelling + no joint widening |
Grade 2 = | subluxation with elevation of clavicle of <5 mm (weight-bearing!) |
Grade 3 = | dislocation with wide AC joint + increased coracoclavicular distance |
Glenohumeral Dislocation (85%)
Glenohumeral joint dislocations make up >50% of all dislocations!
Anterior / Subcoracoid Shoulder Dislocation
(95% of all shoulder dislocations)
Types: | subcoracoid, subglenoid, subclavicular, intrathoracic |
Mechanism: | external rotation + abduction (fall on outstretched arm / hand behind occiput); 40% recurrent |
Age: | in younger individuals in their teens |
Bankart lesion = anterior capsulolabral avulsion = avulsion of anterior-inferior glenoid labrum including labral insertion of inferior glenoid ligament
[Arthur Sydney Blundell Bankart (1879 1951), British orthopedic surgeon]
May be associated with:
bony Bankart fracture of anterior rim of glenoid fracture of greater tuberosity (15%) Hill-Sachs defect (50%) = depression / impacted fracture of posterolateral surface of humeral head at / above level of coracoid process (due to impaction against anterior edge of glenoid rim in subglenoid type) [Harold Arthur Hill (1901 1973) and Maurice David Sachs (1909 1987), radiologists in San Francisco, CA]
P.70
MRI (arthrography improves sensitivity to 89 99%, and specificity to >90%):
hemorrhagic effusion (in acute injury) increased signal intensity in anterior-inferior labrum + capsule (DDx: magic angle artifact) labrum + capsule lifted away from glenoid discrete tear / fragmentation of labrum tear of middle glenohumeral ligament fracture of anterior-inferior glenoid tear of degenerated supraspinatus tendon (in 33% of patients >40 years of age) tear of degenerated subscapularis tendon (in 33% of patients >40 years of age) greater-tuberosity humeral fracture (in 33%) paralabral cysts are usually associated with labral tears; may cause denervation of suprascapular nerve simulating impingement syndrome (DDx: age-related degeneration)
Cx: | (1) Recurrent dislocations (in up to 90% of young active individuals) (2) Repeated dislocations due to incomplete / inadequate healing = chronic recurrent anterior shoulder instability (3) Arthritis (with repeated subluxations) |
Rx: | (1) Conservative treatment for most (2) Surgical fixation for young athletes |
Posterior Shoulder Dislocation (2 4%)
Cause: | (a)traumatic: convulsive disorders /electric shock therapy (b) nontraumatic: voluntary, involuntary, congenital, developmental |
Types: | subacromial, subglenoid, subspinous |
In >50% unrecognized initially + subsequently misdiagnosed as frozen shoulder! Average interval between injury and diagnosis is 1 year! rim sign (66%) = distance between medial border of humeral head + anterior glenoid rim <6 mm
May be associated with:
trough sign (75%) = reverse Hill-Sachs = compression fracture of anteromedial humeral head (tangential Grashey view of glenoid!) fracture of posterior glenoid rim avulsion fracture of lesser tuberosity
MRI:
tear of subscapularis tendon empty bicipital groove (= dislocated bicipital tendon)
Inferior Shoulder Dislocation (1 2%)
= LUXATIO ERECTA
= extremity held over head in fixed position with elbow flexed
Mechanism: | severe hyperabduction of arm resulting in impingement of humeral head against acromion |
humeral articular surface faces inferiorly
Cx: | rotator cuff tear; fracture of acromion inferior glenoid fossa greater tuberosity; neurovascular injury |
No Caption Available. |
Superior Shoulder Dislocation (<1%)
= humeral head driven upward through rotator cuff
May be associated with: | fracture of humerus, clavicle, acromion |
DDx: | drooping shoulder (transient phenomenon after fracture of surgical neck of humerus due to hemarthrosis / muscle imbalance) |
Gadolinium Shoulder Arthrography
fluoroscopically guided needle insertion from an anterior approach confirmation of needle placement with iodinated contrast material injection of 12 20 mL of diluted gadolinium chelate solution: 0.1 mL of gadolinium DTPA (469 mg/mL) into
20 mL of bacteriostatic saline
patient's arm and shoulder are moved through full range of motion
Wrist Dislocation
Mechanism: | fall on outstretched hand |
Incidence: | 10% of all carpal injuries |
Lunate Dislocation
Perilunate Dislocation
2 3 times more common than lunate dislocation
accompanied by fracture in 75% (= transscaphoid perilunate dislocation)
most commonly dorsal dislocation
Rotary Subluxation of Scaphoid
= tearing of interosseous ligaments of lunate, scaphoid, capitate
Mechanism: | acute dorsiflexion of wrist; may be associated with rheumatoid arthritis |
gap >4 mm between scaphoid + lunate (PA view) foreshortening of scaphoid ring sign of distal pole of scaphoid
Midcarpal Dislocation
Down Syndrome
= MONGOLISM = TRISOMY 21
Chromosomes: | 95% nondisjunction, 5% translocation |
Incidence: | 1:870 live births, most common karyotype / chromosomal abnormality in USA |
P.71
mental retardation
hypotonia in infancy
characteristic facies
Simian crease
@ Skull
hypotelorism persistent metopic suture (40 79%) after age 10 hypoplasia of sinuses + facial bones microcrania (brachycephaly) delayed closure of sutures + fontanels dental abnormalities (underdeveloped tooth No. 2) flat-bridged nose
@ Axial skeleton
atlantoaxial subluxation (25%) anterior scalloping of vertebral bodies squared vertebral bodies = centra high and narrow = positive lateral lumbar index (ratio of horizontal to vertical diameters of L2)
@ Chest
congenital heart disease (40%): endocardial cushion defect, VSD, tetralogy of Fallot hypersegmentation of manubrium = 2 3 ossification centers (90%) gracile ribs; 11 pairs of ribs (25%)
@ Pelvis (frontal view)
flaring of iliac wings (= rotation of iliac wings toward coronal plane at sacroiliac joints) = Mickey Mouse ears / elephant ears : decreased iliac angle + index (in 70 80%)
flattening of acetabular roof (small acetabular angle) elongated + tapered ischia
@ Extremities
metaphyseal flaring clinodactyly (50%); widened space between first two digits of hands + feet hypoplastic and triangular middle + distal phalanges of 5th finger = acromicria (DDx: normal individuals, cretins, achondroplastic dwarfs) pseudoepiphyses of 1st + 2nd metacarpals
@ Gastrointestinal
umbilical hernia double bubble sign (8 10%) = duodenal atresia / stenosis / annular pancreas tracheoesophageal fistula anorectal anomalies Hirschsprung disease
OB-US:
advanced maternal age
In 1:385 live births for women >35 years of age HOWEVER: 80% of fetuses with Down syndrome are born to mothers <35 years of age
quad test (2nd trimester maternal serum screening):
low (0.7 MoM) maternal alpha-fetoprotein (20 30%)
increased (2.04 MoM) hCG (DDx: decreased in trisomy 18)
decreased (0.79 MoM) unconjugated estriol (uE3)
decreased dimeric inhibin A levels
optimal time for test between 15 and 16 weeks GA detects 75% of cases with Down syndrome with a 5% screen-positive rate
Disadvantage: late performance in 2nd trimester, 25% of Down syndrome cases not detected, many amniocenteses unnecessarily recommended low pregnancy-associated plasma protein A (PAPP-A @ 10 14 weeks EGA
first-trimester ultrasound markers: nuchal translucency = measurement of space between spine and overlying skin on midsagittal view
Best time: 10w3d 13w6d EGA 5 mm during 14 18 weeks 6 mm during 19 24 weeks Cause: heart failure, abnormal extracellular matrix, abnormal lymphatic development
absent nasal bone Best time: between 10 and 14 weeks EGA absent / reversed Doppler flow in ductus venosus during atrial contraction
major structural malformations: Best time: 18 weeks EGA VSD / complete AV canal (50%) cystic hygroma, resolved by 20th week MA (DDx: Turner syndrome, trisomy 18, trisomy 13, triploidy) omphalocele double bubble of duodenal atresia (8 10%), not apparent before 22 weeks GA hydrothorax mild cerebral ventricular dilatation agenesis of corpus callosum imperforate anus
minor markers: elevated BPD / femur ratio (secondary to short femur) ratio of measured-to-expected femur length 0.91 [expected femur length: 9.3105 + 0.9028 BPD] (sensitivity 40%, specificity 95%, false-positive rate of 2 7%, 0.3% PPV for low-risk population [1:700], 1% PPV for high-risk population [1:250]) ratio of measured-to-expected humerus length 0.90 [expected humerus length: 7.9404 + 0.8492 BPD] (1 2% PPV for low-risk population; 3% PPV for high-risk population) flared iliac crest = iliac wings rotated toward coronal plane: mean iliac angle at superiormost level of 95.6 11.7 (compared to 76.4 16.8 for euploid fetuses)
sandal-gap deformity = separation of great toe (45%) hypoplasia of middle phalanx of 5th digit resulting in clinodactyly (= inward curve) in 60% mild fetal pyelectasis (17 25%) echogenic bowel at <20 weeks GA (15%, in 0.6% of normals) echogenic intracardiac focus, usually in left ventricle = thickening of papillary muscle (18%, in 5% of normals) frontal lobe shortening (measured from the inner table of the frontal bone to the posterior margin of the thalamus) brachycephaly small cerebellum IUGR (in 30%) polyhydramnios
Cx: leukemia (increased frequency 3 20 x)
P.72
Dyschondrosteosis
= L RI-LAYANI-WEILL SYNDROME
= mesomelic long-bone shortening (forearm + leg); autosomal dominant
M:F = 1:4
limited motion of elbow + wrist
bilateral Madelung deformity: radial shortening in relation to ulna bowing of radius laterally + dorsally dorsal subluxation of distal end of ulna carpal wedging between radius + ulna (due to triangular shape of distal radial epiphysis + underdevelopment of ulna)
DDx: | pseudo-Madelung deformity (from trauma / infection) |
Dysplasia Epiphysealis Hemimelica
= TREVOR DISEASE = TARSOEPIPHYSEAL ACLASIS
= uncommon skeletal developmental disorder representing an epiphyseal osteochondroma
Incidence: | 1:1,000,000 |
Age: | 2 4 years; M:F = 3:1 |
Cause: | failure of normal progression of cellular cartilage breakdown (= aclasis); spontaneous occurrence |
Path: | lobulated mass protruding from epiphysis with a cartilaginous cap |
Histo: | normal bone + hyaline cartilage with abundant enchondral ossification (= abnormal cellular activity at cartilaginous ossification center) |
Types:
Localized form = monostotic involvement: usually hindfoot and ankle
Classic form (>66%) = more than one area of involvement in a single extremity with characteristic hemimelic distribution: talus, distal femur, distal tibia
Generalized / severe form = disease involving the whole lower extremity
pelvic involvement: femoral head, symphysis pubis, triradiate cartilage hypertrophy of ipsilateral iliac bone
antalgic (= pain-avoiding) gait; palpable mass
varus / valgus deformity; limb length discrepancy
limited joint mobility and function
Location: | lower extremity (tarsus, knee, ankle); rare in upper extremity (humerus, ulna, scapula) |
Site: | restricted to medial OR lateral side of limb (= hemimelic), ie, medial:lateral = 2:1 |
@ Infant & toddler
premature appearance of an eccentric, lobulated, overgrown, asymmetric ossification center stippled calcification of anomalous cartilage
@ Childhood
disorganized epiphyseal calcification accompanied by irregular ossification osteochondroma-like growth from one side of epiphysis premature closure of physis results in limb deformity and limb length discrepancy irregular articular surface combined with angular deformity undertubulation of bone as a consequence of secondary involvement of metaphysis
Cx: | premature secondary osteoarthritis |
DDx: | osteochondroma |
Echinococcus of Bone
Occurs occasionally in the USA; usually in foreign-born individuals; bone involvement in 1%
Histo: | no connective tissue barrier; daughter cysts extend directly into bone |
Pelvis, sacrum, rarely long tubular bones round / irregular regions of rarefaction multiloculated lesion (bunch of grapes) no sharp demarcation (DDx: chondroma, giant cell tumor) with secondary infection: thickening of trabeculae with generalized perifocal condensation cortical breakthrough with soft-tissue mass
Vertebra sclerosis without pathologic fracture intervertebral disks not affected vertebral lamina often involved frequently involvement of adjacent ribs
Ehlers-Danlos Syndrome
= group of autosomal dominant diseases of connective tissue characterized by abnormal collagen synthesis
Types: | 10 types have been described that differ clinically, biochemically, and genetically |
Age: | present at birth; predominantly in males |
hyperelasticity of skin
fragile brittle skin with gaping wounds and poor healing
molluscoid pseudotumors over pressure points
hyperextensibility of joints
joint contractures with advanced age
bleeding tendency (fragility of blood vessels)
blue sclera, microcornea, myopia, keratoconus, ectopia lentis
@ Soft tissues
multiple ovoid calcifications (2 10 mm) in subcutis / in fatty cysts ( spheroids ), most frequently in periarticular areas of legs ectopic bone formation
@ Skeleton
hemarthrosis (particularly in knee) malalignment / subluxation / dislocation of joints on stress radiographs recurrent dislocations (hip, patella, shoulder, radius, clavicle) precocious osteoarthrosis (predominantly in knees) ulnar synostosis kyphoscoliosis spondylolisthesis spina bifida occulta
@ Chest
diaphragmatic hernia panacinar emphysema + bulla formation tracheobronchomegaly + bronchiectasis
@ Arteries
aneurysm of great vessels, aortic dissection, tortuosity of arch, ectasia of pulmonary arteries AORTOGRAPHY CONTRAINDICATED! (Cx following arteriography: aortic rupture, hematomas)
GI tract ectasia of gastrointestinal tract
P.73
Elastofibroma
= benign tumorlike lesion forming as a reaction to mechanical friction
Incidence: | in 24% of women + 11% of men >55 years (autopsy study) |
Age: | elderly; M:F = 1:2 |
Histo: | enlarged irregular serrated elastic hypereosinophilic fibers, collagen, scattered fibroblasts, occasional lobules of adipose tissue |
asymptomatic
may remain clinically inapparent
Location: between inferior margin of scapula + posterior chest wall; bilateral in 25% inhomogeneous poorly defined lesion of soft-tissue attenuation similar to muscle well-defined intermediate-signal intensity lesion with interlaced areas of fat-intensity signal on T1WI + T2WI
Enchondroma
= benign cartilaginous growth in medullary cavity; bones preformed in cartilage are affected (NOT skull)
Incidence: | 3 17% of biopsied primary bone tumors Second most common cartilage-containing tumor! |
Etiology: | continued growth of residual benign rests of cartilage displaced from the growth plate |
Age: | 10 30 years; M:F = 1:1 |
Histo: | lobules of pure hyaline cartilage |
usually asymptomatic, painless swelling
Location: | (usually solitary; multiple = enchondromatosis) (a) in 40% small tubular bones of wrists + hand (most frequent tumor here), distal + mid aspects of metacarpals, proximal / middle phalanges (b) proximal femur, proximal humerus, tibia, radius, ulna, foot, rib (3%) |
Site: | central within medullary canal + metaphyseal; epiphysis only affected after closure of growth plate |
oval / round area of geographic destruction with lobulated contour + fine marginal line cortical endosteal scalloping ground-glass appearance dystrophic calcifications within small cartilage nodules / fragments of lamellar bone: pinhead, stippled, flocculent, rings and arcs pattern bulbous expansion of bone with thinning of cortex in small tubular bones of phalanx, rib, fibula Madelung deformity = bowing deformities of limb, discrepant length NO cortical breakthrough / periosteal reaction MR:
low- to intermediate-signal intensity on T1WI + high-signal intensity on T2WI low-signal intensity matrix calcifications normal fat marrow interspersed between cartilage nodules peripheral enhancement pattern
Cx: | (1) Pathologic fracture (2) Malignant degeneration in long-bone enchondromas in 15 20% (gradually increasing pain in an adult patient) |
DDx: | (1) Epidermoid inclusion cyst (phalangeal tuft, history of trauma, more lucent) (2) Unicameral bone cyst (rare in hands, more radiolucent) (3) Giant cell tumor of tendon sheath (commonly erodes bone, soft-tissue mass outside bone) (4) Fibrous dysplasia (rare in hand, mostly polyostotic) (5) Bone infarct (6) Chondrosarcoma (exceedingly rare in phalanges, metacarpals, metatarsals) |
Enchondromatosis
= OLLIER DISEASE = DYSCHONDROPLASIA = MULTIPLE ENCHONDROMATOSIS
= nonhereditary failure of cartilage ossification
Cause: | derangement of cartilaginous growth resulting in migration of cartilaginous rests from epiphyseal plate into metaphysis where they proliferate |
Age: | early childhood presentation |
Association: | juvenile granulosa cell tumor of ovary |
growth disparity with leg / arm shortening
hand + feet deformity
Location: | predominantly unilateral monomelic distribution (a) localized (b) regional (c) generalized |
well-demarcated rounded radiolucencies / columnar streaks of decreased density from epiphyseal plate into diaphysis of long bones = cartilaginous rests expansile remodeling of affected bone: clublike deformity / expansion of metaphyseal region predominant thinning of cortex + endosteal scalloping bony spurs pointing toward the joint (DDx: exostosis points away from it)
cartilaginous areas show punctate calcifications with age: matrix mineralization with TYPICAL arc-and-ring appearance of chondroid lesions
associated with dwarfing of the involved bone due to impairment of epiphyseal fusion bowing deformities of limb bones discrepancy in length = Madelung deformity (radius, ulna) small bones of feet + hands: aggressive deforming tumors that may break through cortex secondary to tendency to continue to proliferate fanlike radiation of cartilage from center to crest of ilium
Cx: | sarcomatous transformation (in 25 30%): osteosarcoma (young adults); chondro- / fibrosarcoma (in older patients) |
Maffucci Syndrome
= nonhereditary mesodermal dysplasia characterized by enchondromatosis + multiple soft-tissue cavernous hemangiomas + less commonly lymphangiomas
Age: 25% during 1st year of life; 45% prior to 6 years; 78% before puberty; M > F Association: juvenile granulosa cell tumor of ovary multiple blue subcutaneous nodules particularly on digits + extremities (cavernous hemangiomas)
normal intelligence
Location: unilateral involvement (50%) / marked asymmetry; distinct predilection for tubular bones of hands + feet P.74
phleboliths may be present striking tendency for enchondromas to be very large projecting into soft tissues growth disturbance of long bones (common)
Cx: (a) malignant transformation of (1) Enchondroma to chondrosarcoma / fibrosarcoma (15 20%)
(2) Cavernous hemangioma to hemangiosarcoma / hemangioendothelioma / lymphangiosarcoma (in 3 5%)
(b) increased prevalence of ovarian carcinoma, pancreatic carcinoma, CNS glioma, gastrointestinal adenocarcinoma
Prevalence of malignancy: 23 100%
DDx: Ollier disease (without hemangiomas)
Engelmann-Camurati Disease
= PROGRESSIVE DIAPHYSEAL DYSPLASIA = CAMURATI-ENGELMANN DISEASE
Cause: | autosomal dominant; disturbance in intramembranous bone formation + modeling (as occurs in cortex of long bones, calvaria, mandible, facial bones, midsegment of clavicle) |
Age: | 5 25 years (primarily in childhood); M > F |
neuromuscular dystrophy = delayed walking (18 24 months) with wide-based waddling gait; often misdiagnosed as muscular dystrophy / poliomyelitis
weakness + easy fatigability in legs
bone pain + tenderness usually in midshaft of long bones
underdevelopment of muscles secondary to malnutrition
NORMAL laboratory values
Location: | usually symmetrical; NO involvement of hands, feet, ribs, scapulae |
@ Skull (initially affected)
amorphous increase in density at base of skull encroachment of frontal + sphenoid sinus; sparing of maxillary sinus
@ Long bones (bilateral symmetrical distribution)
Site: tibia > femur > fibula > humerus > ulna > radius fusiform enlargement of diaphyses with cortical thickening (endosteal + periosteal accretion of mottled new bone) and progressive obliteration of medullary cavity progression of lesions along long axis of bone toward either end abrupt demarcation of lesions (metaphyses + epiphyses spared) relative elongation of extremities
DDx: | (1) Chronic osteomyelitis (single bone) (2) Hyperphosphatasemia (high alkaline phosphatase levels) (3) Paget disease (age, new-bone formation, increased alkaline phosphatase) (4) Infantile cortical hyperostosis (fever; mandible, rib, clavicles; regresses, <1 year of age) (5) Fibrous dysplasia (predominantly unilateral, subperiosteal new bone) (6) Osteopetrosis (very little bony enlargement) (7) Vitamin A poisoning |
Epidermoid Cyst
= INFUNDIBULAR CYST
= proliferation of surface epidermal cells within the dermis
Histo: production of keratin within closed space lined by surface epidermis Associated with: nevoid basal cell syndrome (Gorlin syndrome) patients have a high prevalence of epidermoid / dermoid cysts isointense / slightly hyperintense relative to muscle on T1WI hyperintense with focal areas of decreased signal on T2WI
Epidermoid Inclusion Cyst
= INTRAOSSEOUS KERATIN CYST = IMPLANTATION CYST
Age: | 2nd 4th decade; M > F |
Histo: | stratified squamous epithelium, keratin, cholesterol crystals (soft white cheesy contents) |
history of trauma (implantation of epithelium under skin with secondary bone erosion)
asymptomatic
Location: | superficially situated bones such as calvarium (typically in frontal / parietal bone), phalanx (usually terminal tuft of middle finger), L > R hand, occasionally in foot |
well-defined round osteolysis with sclerotic margin cortex frequently expanded + thinned NO calcifications / periosteal reaction / soft-tissue swelling pathologic fracture often without periosteal reaction
DDx: | (a) in finger: glomus tumor, enchondroma (rare in terminal phalanx) (b) in skull: infection, metastasis (poorly defined), eosinophilic granuloma (beveled margin) |
Epiphyseolysis of Femoral Head
= SLIPPED CAPITAL FEMORAL EPIPHYSIS
= atraumatic fracture through hypertrophic zone of physeal plate
Frequency: | 2:100,000 people |
Etiology: | growth spurt, renal osteodystrophy, rickets, childhood irradiation, growth hormone therapy, trauma (Salter-Harris type I epiphyseal injury) |
Pathogenesis: | widening of physeal plate during growth spurt + change in orientation of physis from horizontal to oblique increases shear forces |
Age: | overweight 8 17 year old boys (mean age for boys 13, for girls 11 years); M:F = 3:1; black > white |
Associated with:
malnutrition, endocrine abnormality, developmental dysplasia of hip (during adolescence)
delayed skeletal maturation (after adolescence)
hip pain (50%) / knee pain (25%) for 2 3 weeks
Location: | usually unilateral; bilateral in 20 37% (at initial presentation in 9 18%) |
widening of epiphyseal growth plate (preslip phase): irregularity + blurring of physeal physis demineralization of neck metaphysis
posteromedial displacement of head (acute slip): decrease in neck-shaft angle with alignment change in the growth plate to a more vertical orientation line of Klein (= line drawn along superior edge of femoral neck) fails to intersect the femoral head Line of Klein in Normal Hip
epiphysis appears smaller due to posterior slippage: early slips are best seen on cross-table LAT view
CAVE: positioning into a frog leg view may cause further displacement
P.75
sclerosis + irregularity of widened physis (chronic slip): metaphyseal blanch sign = area of increased opacity in proximal part of metaphysis (healing response)
Grading (based on femoral head position):
mild | = | displaced by <1/3 of metaphyseal diameter |
moderate | = | displaced by 1/3 2/3 of diameter |
severe | = | displaced by >2/3 of metaphyseal diameter |
Cx: | (1) Chondrolysis = acute cartilage necrosis (7 10%) = rapid loss of >50% of thickness of cartilage joint space <3 mm (2) Avascular necrosis of femoral head (10 15%): risk increases with advanced degree of slip, delayed surgery for acute slip, anterior pin placement, large number of fixation pins, subcapital osteotomy (3) Pistol-grip deformity = broadening + shortening of femoral neck in varus deformity (4) Degenerative osteoarthritis (90%) (5) Limb-length discrepancy due to premature physeal closure |
Rx: | (1) limitation of activity (2) prophylactic pinning (3) osteotomy Attempted reductions increase risk of AVN! |
Essential Osteolysis
= progressive slow bone-resorptive disease
Histo: | proliferation + hyperplasia of smooth muscle cells of synovial arterioles |
progressive osteolysis of carpal + tarsal bones thinned pointed proximal ends of metacarpals + metatarsals elbows show same type of destruction bathyrocephalic depression of base of skull
DDx: | (1) Massive osteolysis = Gorham disease (local destruction of contiguous bones, usually not affecting hands / feet) (2) Mutilating forms of rheumatoid arthritis (3) Tabes dorsalis (4) Leprosy (5) Syringomyelia (6) Scleroderma (7) Raynaud disease (8) Regional posttraumatic osteolysis (9) Ulcero-mutilating acropathy (10) Mutilating forms of rheumatoid arthritis (11) Acrodynia mutilante (nonhereditary) |
Ewing Sarcoma
= EWING TUMOR
Incidence: | 4 10% of all bone tumors (less common than osteo- / chondrosarcoma); most common malignant bone tumor in children; 4th most common bone tumor overall |
Clinically, radiologically, and histologically very similar to PNET!
Histo: | small round cells, uniformly sized + solidly packed (DDx: lymphoma, osteosarcoma, myeloma, neuroblastoma, carcinoma, eosinophilic granuloma) invading medullary cavity and entering subperiosteum via Haversian canals producing periostitis, soft-tissue mass, osteolysis; glycogen granules present (DDx to reticulum cell sarcoma); absence of alkaline phosphatase (DDx to osteosarcoma); MIC2 cell surface immunoreactivity (in 100%) |
Age: | peak 15 years (range 5 months to 54 years); in 95% 4 25 years; in 30% <10 years; in 39% 11 15 years; in 31% >15 years; in 50% <20 years;M:F = 1:2; Caucasians in 96% |
severe localized pain
soft-tissue mass
fever, leukocytosis, anemia (in early metastases) simulating infection
Location:
femur (25%), pelvis-ilium (14%), tibia (11%), humerus (10%), fibula (8%), ribs (6 10%)
long bones in 60%: metadiaphysis (44%), middiaphysis (33%), metaphysis (15%), metaepiphyseal (6%), epiphyseal (2%); usually no involvement of epiphysis as tumor originates in medullary cavity with invasion of Haversian system
flat bones in 40%: pelvis, scapula, skull, vertebrae (in 3 10%; sacrum > lumbar > thoracic > cervical spine); ribs (in 7% > age 10; in 30% < age 10)
>20 years of age predominantly in flat bones <20 years of age predominantly in cylindrical bones (tumor derived from red marrow)
8 10 cm long lytic lesion in shaft of long bone (62% lytic, 23% mixed density, 15% dense) mottled moth-eaten destructive permeative lesion (72%) (late finding) penetration into soft tissue (55%) with preservation of tissue planes (DDx: osteomyelitis with diffuse soft-tissue swelling) early fusiform lamellated onionskin periosteal reaction (53%) / spiculated = sunburst / hair-on-end (23%), Codman triangle cortical thickening (16%) cortical destruction (18%) cortical sequestration reactive sclerotic new bone (30%) bone expansion (12%) @ Ewing sarcoma of rib:
primarily lytic / sclerotic / mixture of lysis + sclerosis disproportionately large inhomogeneous soft-tissue mass large intrathoracic + minimal extrathoracic component may spread into spinal canal via intervertebral foramen
P.76
Metastases to: | lung, bones, regional lymph nodes in 11 30% at time of diagnosis, in 40 45% within 2 years of diagnosis |
Cx: | pathologic fracture (5 14%) |
Prognosis: | 60 75% 5-year survival |
DDx: | (1) Multiple myeloma (older age group) (2) Osteomyelitis (duration of pain <2 weeks) (3) Eosinophilic granuloma (solid periosteal reaction) (4) Osteosarcoma (ossification in soft tissue, near age 20, no lamellar periosteal reaction) (5) Reticulum cell sarcoma (clinically healthy, between 30 and 50 years, no glycogen) (6) Neuroblastoma (< age 5) (7) Anaplastic metastatic carcinoma (>30 years of age) (8) Osteosarcoma (9) Hodgkin disease |
Extramedullary Hematopoiesis
= compensatory response to deficient bone marrow blood cell production
Etiology: prolonged erythrocyte deficiency due to destruction of RBC:
congenital hemolytic anemia (sickle cell anemia, thalassemia, hereditary spherocytosis), acquired hemolytic anemia, idiopathic severe anemia, erythroblastosis fetalis
inability of normal blood-forming organs to produce erythrocytes: iron deficiency anemia, pernicious anemia, myelofibrosis, myelosclerosis, polycythemia vera, carcinomatous / lymphomatous replacement depletion of bone marrow (chronic myelogenous leukemia, Hodgkin disease)
NO hematologic disease in 25%
absence of pain, bone erosion, calcification
chronic anemia
Sites: in areas of fetal erythropoiesis @ spleen
splenomegaly focal isodense masses on enhanced CT
@ liver, lymph nodes
@ thorax: mediastinum, heart, thymus, lung
uni- / bilateral smooth lobulated paraspinal masses between T8 and T12 anterior rib ends expanded by masses
@ Spine
Most commonly afflicted in thalassemia back pain, symptoms of spinal cord compression
coarsened trabeculation extramedullary hematopoiesis in epidural space
@ adrenal glands
@ renal pelvis
@ gastrointestinal lymphatics
@ dura mater (falx cerebri and over brain convexity)
@ cartilage, broad ligaments
@ thrombi, adipose tissue
@ Bone marrow reconversion = conversion of fatty to hematopoietic marrow
Sequence: vertebrae > flat bones of pelvis > long bones of extremities (proximal metaphysis > distal metaphysis > diaphysis) lack of calcification / bone erosion
Familial Idiopathic Acroosteolysis
= HAJDU-CHENEY SYNDROME
= rare bizarre entity of unknown etiology
Location: may be unilateral fingernails remain intact sensory changes + plantar ulcers rare
pseudoclubbing of fingers + toes with osteolysis of terminal + more proximal phalanges genu varum / valgum hypoplasia of proximal end of radius subluxation of radial head scaphocephaly, basilar impression wide sutures, persistent metopic suture, Wormian bones, poorly developed sinuses kyphoscoliosis severe osteoporosis + fractures at multiple sites (esp. of spine) protrusio acetabuli
Fanconi Anemia
= autosomal recessive disease with severe hypoplastic anemia + skin pigmentation + skeletal and urogenital anomalies
skin pigmentation (melanin deposits) in 74% (trunk, axilla, groin, neck)
anemia onset between 17 months and 22 years of age
bleeding tendency (pancytopenia)
hypogonadism (40%)
microphthalmia (20%)
anomalies of radial component of upper extremity (strongly suggestive): absent / hypoplastic / supernumerary thumb hypoplastic / absent radius absent / hypoplastic navicular / greater multangular bone
slight / moderate dwarfism minimal microcephaly renal anomalies (30%): renal aplasia, ectopia, horseshoe kidney
Prognosis: | fatal within 5 years after onset of anemia; patient's family shows high incidence of leukemia |
Farber Disease
= DISSEMINATED LIPOGRANULOMATOSIS
Histo: | foam cell granulomas; lipid storage of neuronal tissue (accumulation of ceramide + gangliosides) |
hoarse weak cry
swelling of extremities; generalized joint swelling
subcutaneous + periarticular granulomas
intermittent fever, dyspnea
lymphadenopathy
capsular distension of multiple joints (hand, elbow, knee) juxtaarticular bone erosions from soft-tissue granulomas subluxation / dislocation disuse / steroid deossification
Prognosis: | death from respiratory failure within 2 years |
Femoroacetabular impingement
= repetitive microtrauma due to an anatomic conflict between proximal femur + acetabular rim at extreme range of motion
Age: | 2nd 3rd decade; in patients with increased sports activity |
Femoroacetabular Impingement |
P.77
Types:
Cam FAI
= nonspherical shape of femoral head with reduced depth of femoral waist leads to abutment of femoral head-neck junction against acetabular rim
osseous bump deforming femoral head-neck junction (50%) a-angle of >55 (measured at the anterosuperior position on radial images rotated around center line of femoral neck) cartilage lesions at anterosuperior acetabulum at posterior and posteroinferior acetabulum (pincer FAI)
Pincer FAI
= acetabular overcoverage limits range of motion
Cause: protrusio acetabuli, acetabular retroversion deep acetabulum (head center >5 mm below rim) osseous bump deforming femoral head-neck junction (33%) cartilage lesions at posterior and posteroinferior acetabulum (countercoup damage)
ossification of acetabular rim separate bone fragment / os acetabuli Cx: premature osteoarthritis initially with cartilage damage + labral tears Rx: surgery in patients without osteoarthritis consisting of reshaping of femoral waist / trimming of acetabular rim / periacetabular osteotomy
Fibrochondrogenesis
= autosomal recessive lethal short-limb skeletal dysplasia
Incidence: | 5 cases |
severe micromelia + broad dumbbell-shaped metaphyses flat + clefted pear-shaped vertebral bodies short + cupped ribs frontal bossing low-set abnormally formed ears
Prognosis: | stillbirth / death shortly after birth |
DDx: | (1) Thanatophoric dysplasia (2) Metatropic dysplasia (3) Spondyloepiphyseal dysplasia |
Fibrodysplasia Ossificans Progressiva
= MYOSITIS OSSIFICANS PROGRESSIVA (misnomer since primarily connective tissues are affected)
= rare slowly progressive sporadic / autosomal dominant disease with variable penetrance characterized by remissions + exacerbations of fibroblastic proliferation, subsequent calcification + ossification of subcutaneous fat, skeletal muscle, tendons, aponeuroses, ligaments
Histo: | edema with proliferating fibroblasts in a loose myxoid matrix; subsequent collagen deposition plus calcification + ossification of collagenized fibrous tissue in the center of nodules |
Age: | presenting by age 2 years (50%) |
initially subcutaneous painful masses on neck, shoulders, upper extremities
progressive involvement of remaining musculature of back, chest, abdomen, lower extremities
lesions may ulcerate and bleed
muscles of back + proximal extremities become rigid followed by thoracic kyphosis
inanition secondary to jaw trismus (masseter, temporal muscle)
wry neck = torticollis (due to restriction of sternocleidomastoid muscle)
respiratory failure (thoracic muscles affected)
conductive hearing loss (fusion of middle ear ossicles)
ECTOPIC OSSIFICATION
rounded / linear calcification in neck / shoulders, paravertebral region, hips, proximal extremity, trunk, palmar + plantar fascia forming ossified bars + bony bridges ossification of voluntary muscles, complete by 20 25 years (sparing of sphincters + head)
SKELETAL ANOMALIES
may appear before ectopic ossification
clinodactyly
microdactyly of big toes (90%) and thumbs (50%) = usually only one large phalanx present / synostosis of metacarpal + proximal phalanx (first sign) phalangeal shortening of hand + foot (middle phalanx of 5th digit) shortened 1st metatarsal + hallux valgus (75%) shortened metacarpals + metatarsals shallow acetabulum short widened femoral neck thickening of medial cortex of tibia progressive fusion of posterior arches of cervical spine narrowed AP diameter of cervical + lumbar vertebral bodies bony ankylosis
CAVE: | surgery is hazardous causing accelerated ossification at the surgical site |
Fibroma of Soft Tissue
Histo: | hypocellular highly collagenic tumor |
Age: | 3rd and 4th decades; M > F |
Location: | tendon sheath of distal upper extremity |
slowly growing lesion 1 5 cm in size MR:
small hypointense nodule on all pulse sequences
Fibrosarcoma
Incidence: | 4% of all primary bone neoplasm |
Etiology:
PRIMARY FIBROSARCOMA (70%)
SECONDARY FIBROSARCOMA (30%)
following radiotherapy of giant cell tumor / lymphoma / breast cancer
underlying benign lesion: Paget disease (common); giant cell tumor, bone infarct, osteomyelitis, desmoplastic fibroma, enchondroma, fibrous dysplasia (rare)
dedifferentiation of low-grade chondrosarcoma
P.78
Histo: | spectrum of well to poorly differentiated fibrous tissue proliferation; will not produce osteoid / chondroid / osseous matrix |
Age: | predominantly in 3rd 5th decade (range of 8 88 years); M:F = 1:1 |
Metastases to: | lung, lymph nodes |
localized painful mass
Location: | tubular bones in young, flat bones in older patients; femur (40%), tibia (16%) (about knee in 30 50%), jaw, pelvis (9%); rare in small bones of hand + feet or spinal column |
Site: | eccentric at diaphyseal-metaphyseal junction into metaphysis; intramedullary / periosteal |
CENTRAL FIBROSARCOMA
= intramedullary
well-defined lucent bone lesion thin expanded cortex aggressive osteolysis with geographic / ragged / permeative bone destruction + wide zone of transition occasionally large osteolytic lesion with cortical destruction, periosteal reaction + soft-tissue invasion sequestration of bone may be present (DDx: eosinophilic granuloma, bacterial granuloma) sparse periosteal proliferation (uncommon) intramedullary discontinuous spread no calcification DDx: malignant fibrous histiocytoma, myeloma, telangiectatic osteosarcoma, lymphoma, desmoplastic fibroma, osteolytic metastasis
PERIOSTEAL FIBROSARCOMA
= rare tumor arising from periosteal connective tissue
Location: long bones of lower extremity, jaw contour irregularity of cortical border periosteal reaction with perpendicular bone formation may be present rarely extension into medullary cavity
Cx: | pathologic fracture (uncommon) |
Prognosis: | 20% 10-year survival |
DDx: | (1) Osteolytic osteosarcoma (2nd 3rd decade) (2) Chondrosarcoma (usually contains characteristic calcifications) (3) Aneurysmal bone cyst (eccentric blown-out appearance with rapid progression) (4) Malignant giant cell tumor (begins in metaphysis extending toward joint) |
Fibrous Cortical Defect
Incidence: | 30% of children; M:F = 2:1 |
Age: | peak age of 7 8 years (range of 2 10 years); mostly before epiphyseal closure |
Histo: | fibrous tissue from periosteum invading underlying cortex |
asymptomatic
Location: | metaphyseal cortex of long bone; posterior medial aspect of distal femur, proximal tibia, proximal femur, proximal humerus, ribs, ilium, fibula |
round when small, average diameter of 1 2 cm oval, extending parallel to long axis of host bone cortical thinning + expansion may occur smooth, well-defined / scalloped margins larger lesions are multilocular involution over 2 4 years
Prognosis:
potential to grow and encroach on the medullary cavity leading to nonossifying fibroma
bone islands in the adult may be residue of incompletely involuted cortical defect
Fibrous Dysplasia
= FIBROUS OSTEODYSTROPHY = OSTEODYSTROPHIA FIBROSA = OSTEITIS FIBROSA DISSEMINATA = LICHTENSTEIN-JAFF DISEASE
= benign fibroosseous developmental anomaly of the mesenchymal precursor of bone, manifested as a defect in osteoblastic differentiation and maturation
Cause: | probable gene mutation during embryogenesis |
Age: | 1st 2nd decade (highest incidence between 3 and 15 years), 75% before age 30; progresses until growth ceases; M:F = 1:1 |
Path: | spongiosa of medullary cavity filled by abnormal fibrous tissue containing poorly calcified trabeculae |
Histo: | matrix of immature collagen contains small irregularly shaped trabeculae of immature, inadequately mineralized woven bone; trabeculae not rimmed by osteoblasts (DDx from ossifying fibroma); cartilaginous islands present in 10% (DDx: chondrosarcoma) |
Clinical Types:
MONOSTOTIC FORM (70 80%)
usually asymptomatic until 2nd 3rd decade
Location: ribs (28%), proximal femur (23%), tibia, craniofacial bones (10 25%), humerus
POLYOSTOTIC FORM (20 30%)
Age: mean age of 8 years 2/3 symptomatic by age 10
leg pain, limp, pathologic fracture (75%)
abnormal vaginal bleeding (25%)
coast of Maine caf -au-lait spots = few yellowish to brownish dark patches of cutaneous pigmentation with irregular / serrated border, predominantly on back of trunk (30 50%), buttocks, neck, shoulders; often ipsilateral to bone lesions (DDx: more numerous and lighter coast of California spots of neurofibromatosis)
Associated with: endocrinopathy (in 2 3%) Location: usually unilateral + asymmetric; femur (91%), tibia (81%), pelvis (78%), foot (73%), ribs, skull + facial bones (50%), upper extremities, lumbar spine (14%), clavicle (10%), cervical spine (7%) Site: metadiaphysis
leg length discrepancy (70%) shepherd's crook deformity (35%) facial asymmetry tibial bowing rib deformity ray pattern = involvement of all phalanges + metacarpal bone of a single digit
CRANIOFACIAL FORM = LEONTIASIS OSSEA
Incidence: in 10 25% of monostotic form / in 50% of polyostotic form / isolated cranial asymmetry
facial deformity
nasal stuffiness
proptosis
visual impairment / unilateral blindness
Location: sphenoid, frontal, maxillary, ethmoid bones > occipital, temporal bones
unilateral overgrowth of facial bones + calvarium (NO extracranial lesions) outward expansion of outer table maintaining convexity (DDx: Paget disease with destruction of inner + outer table) prominence of external occipital protuberance Cx: neurologic deficit secondary to narrowed cranial foramina (eg, blindness)
CHERUBISM (special variant)
= FAMILIAL FIBROUS DYSPLASIA
= autosomal dominant disorder of variable penetrance
Age: childhood; more severe in males bilateral jaw fullness + slight upward turning of eyes
bilateral expansile multiloculated cystic masses with symmetric involvement of mandible + maxilla Cx: problems with dentition after perforation of cortex Prognosis: regression after adolescence
P.79
May be associated with:
endocrine disorders:
precocious puberty in girls
hyperthyroidism
hyperparathyroidism: renal stones, calcinosis
acromegaly
diabetes mellitus
Cushing syndrome: osteoporosis, acne
growth retardation
soft-tissue myxoma (rare) = Mazabraud syndrome: typically multiple intramuscular lesions in vicinity of most severely affected bone
VARIANT: | McCune-Albright syndrome (10%) |
Sex: | almost exclusively in girls |
polyostotic unilateral fibrous dysplasia
coast of Maine caf -au-lait spots (35%)
endocrinopathy: peripheral sexual precocity (menarche in infancy [20%]), hyperthyroidism
swelling + tenderness
limp, pain ( pathologic fracture)
increased alkaline phosphatase
advanced skeletal + somatic maturation (early)
Common location: rib cage (30%), craniofacial bones [calvarium, mandible] (25%), femoral neck + tibia (25%), pelvis Site: metaphysis is primary site with extension into diaphysis (rarely entire length) normal bone architecture altered + remodeled lesions in medullary cavity: radiolucent / ground-glass appearance / increased density trabeculated appearance due to reinforced subperiosteal bone ridges in wall of lesion expansion of cortices (ribs, skull, long bones) with blown-out appearance well-defined sclerotic margin of reactive bone = rind endosteal scalloping with thinned / lost cortex (ribs, long bones) and intervening normal cortex is HALLMARK lesion may undergo calcification + enchondral bone formation = fibrocartilaginous dysplasia increased activity on bone scan during early perfusion + on delayed images
CT:
Most cases of monostotic fibrous dysplasia are incidental findings on a cranial CT examination! ground-glass lucencies sclerotic margins + well-defined borders expansion of bone
MR:
MRI should not be used to differentiate fibrous dysplasia from other entities due to the extreme variability in the appearance of the bone lesions! homogeneous / mildly heterogeneous marrow lesions hyperintense to fat (60%) / of intermediate / of low signal intensity on T2WI marrow lesions hypointense to muscle on T1WI
NUC:
increased tracer uptake on bone scans (lesions remain metabolically active into adulthood)
@ Skull
skull deformity with cranial nerve compromise
proptosis
Location: frontal bone > sphenoid bone; hemicranial involvement (DDx: Paget disease is bilateral) blistering / bubbling cystic calvarial lesions (CHARACTERISTIC), commonly crossing sutures sclerotic skull base, may narrow neural foramina (visual + hearing loss) widened diploic space with displacement of outer table, inner table spared (DDx: Paget disease, inner table involved) obliteration of sphenoid + frontal sinuses due to encroachment by fibrous dysplastic bone inferolateral displacement of orbit sclerosis of orbital plate + small orbit + hypoplasia of frontal sinuses (DDx: Paget disease, meningioma en plaque) occipital thickening mandibular cystic lesion (very common) = osteocementoma, ossifying fibroma
@ Pelvis + ribs
bubbly cystic lesions (extremely common) fusiform enlargement of ribs + loss of normal trabecular pattern + thin preserved cortex (in up to 30%) Fibrous dysplasia is the most common cause of a benign expansile lesion of a rib! A rib is the most common site of monostotic fibrous dysplasia!
protrusio acetabuli
@ Extremities
short stature as adult / dwarfism
premature fusion of ossification centers epiphysis rarely affected before closure of growth plate bowing deformities + discrepant limb length (tibia, femur) due to stress of normal weight bearing shepherd's crook deformity of femoral neck = coxa vara pseudarthrosis in infancy = osteofibrous dysplasia (DDx: neurofibromatosis) premature onset of arthritis
P.80
Cx: (1) Dedifferentiation into osteo- / fibro- / (rarely) chondrosarcoma or malignant fibrous histiocytoma (0.5 1%, more often in polyostotic form) increasing pain
enlarging soft-tissue mass
previously mineralized lesion turns lytic
(2) Pathologic fractures: transformation of woven into lamellar bone may be seen, subperiosteal healing without endosteal healing
DDx:
Paget disease (mosaic pattern histologically, radiographically similar to monostotic cranial lesion, outer table involved, sparing of facial bones)
Neurofibromatosis (rarely osseous lesions, vertebral column is primary target, ribbon ribs, cystic intraosseous neurofibroma rare, caf -au-lait spots smooth, familial disease)
HPT (principally histologic problem, chemical changes, generalized deossification, subperiosteal resorption)
Osteofibrous dysplasia (almost exclusively in tibia of children <10 years + anterior bowing, monostotic, lesion begins in cortex, spontaneous regression)
Nonossifying fibroma
Simple bone cyst
Giant cell tumor (no sclerotic margin)
Enchondromatosis
Eosinophilic granuloma (beveled margin in skull, black hole on CT of lower density)
Osteoblastoma
Hemangioma
Meningioma
Prognosis: bone lesions usually do not progress beyond puberty
Fibrous Histiocytoma
Benign Fibrous Histiocytoma
Incidence: | 0.1% of all bone tumors |
Histo: | interlacing bundles of fibrous tissue in storiform pattern (whorled / woven) interspersed with mono- / multinucleated cells resembling histiocytes, benign giant cells, and lipid-laden macrophages; resembles nonossifying fibroma / fibroxanthoma |
Age: | 23 60 years |
localized intermittently painful soft-tissue swelling
Location: | long bone, pelvis, vertebra (rare) |
Site: | typically in epiphysis / epiphyseal equivalent |
well-defined radiolucent lesion with septa / soap-bubble appearance / no definable matrix may have reactive sclerotic rim narrow transition zone (= nonaggressive lesion) no periosteal reaction
Rx: | curettage |
DDx: | nonossifying fibroma (childhood / adolescence, asymptomatic, eccentric metaphyseal location) |
Atypical Benign Fibrous Histiocytoma
Histo: | atypical aggressive features = mitotic figures present |
lytic defect with irregular edges
Prognosis: | may metastasize |
Malignant Fibrous Histiocytoma
= MFH = MALIGNANT FIBROUS XANTHOMA = XANTHO-SARCOMA = MALIGNANT HISTIOCYTOMA = FIBRO-SARCOMA VARIANT
Histo: | spindle-cell neoplasm of a mixture of fibroblasts + giant cells resembling histiocytes with nuclear atypia and pleomorphism in pinwheel arrangement; closely resembles high-grade fibrosarcoma (= fibroblastic cells arranged in uniform pattern separated by collagen fibers) (a) pleomorphic-storiform subtype (50 60%) (b) myxoid subtype (25%) (c) giant cell subtype (5 10%) (d) inflammatory subtype (5 10%) (e) angiomatoid subtype (<5%) |
Age: | 10 90 (average 50) years; peak prevalence in 5th decade; more frequent in Caucasians; M:F = 3:2 |
Location: | potential to arise in any organ (ubiquitous mesenchymal tissue); soft tissues >> bone |
Soft-tissue MFH
Incidence: | 20 30% of all soft-tissue sarcomas; most common primary malignant soft-tissue tumor of late adult life |
Any deep-seated invasive intramuscular mass in a patient >50 years of age is most likely MFH!
Location: | extremities (75%), [lower extremity (50%), upper extremity (25%)], retroperitoneum (15%), head + neck (5%) |
Site: | within large muscle groups |
large painless soft-tissue mass with progressive enlargement over several months
mass usually 5 10 cm in size with increase over months / years poorly defined curvilinear / punctate peripheral calcifications / ossifications (in 5 20%) cortical erosion of adjacent bone (HIGHLY SUGGESTIVE FEATURE) CT:
well-defined soft-tissue mass with central hypodense area = myxoid MFH (DDx: hemorrhage, necrosis, leiomyosarcoma with necrosis, myxoid lipo- / chondrosarcoma) enhancement of solid components
MR:
inhomogeneous poorly defined lesion iso- / hyperintense to muscle on T1WI + hyperintense on T2WI
Prognosis: | larger + more deeply located tumors have a worse prognosis; 2-year survival rate of 60%; 5-year survival rate of 50%; local recurrence rate of 44%; metastatic rate of 42% (lung, lymph nodes, liver, bone) |
DDx: | (1) Liposarcoma (younger patient, presence of fat in >40%, calcifications rare) (2) Rhabdomyosarcoma (3) Synovial sarcoma (cortical erosion) |
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Osseous MFH
Prevalence: | 5% of all primary malignant bone tumors |
painful, tender, rapidly enlarging mass
pathologic fracture (20%)
Associated with: | prior radiation therapy, bone infarcts, Paget disease, fibrous dysplasia, osteonecrosis, fibroxanthoma (= nonossifying fibroma), enchondroma, chronic osteomyelitis |
20% of all osseous MFH arise in areas of abnormal bone!
Location: | femur (45%), tibia (20%), 50% about knee; humerus (10%); ilium (10%); spine; sternum; clavicle; rarely small bones of hand + feet |
Site: | central metaphysis of long bones (90%); eccentric in diaphysis of long bones (10%) |
radiolucent defect with ill-defined margins (2.5 10 cm in diameter) extensive mineralization / small areas of focal metaplastic calcification permeation + cortical destruction expansion in smaller bones (ribs, sternum, fibula, clavicle) occasionally lamellated periosteal reaction (especially in presence of pathologic fracture) soft-tissue extension
Cx: | pathologic fracture (30 50%) |
DDx: | (1) Metastasis (2) Fibrosarcoma (often with sequestrum) (3) Reticulum cell sarcoma (4) Osteosarcoma (5) Giant cell tumor (6) Plasmacytoma |
Pulmonary MFH (extremely rare)
solitary pulmonary nodule without calcification diffuse infiltrate NUC:
increased uptake of Tc-99m MDP (mechanism not understood) increased uptake of Ga-67 citrate
US:
well-defined mass with hyperechoic + hypoechoic (necrotic) areas
CT:
mass of muscle density with hypodense areas (necrosis) invasion of abdominal musculature, but not IVC / renal veins (DDx to renal cell carcinoma)
Angio:
hypervascularity + early venous return
Focal Fibrocartilaginous Dysplasia of Tibia
Associated with: | tibia vara |
Age: | 9 28 months |
Histo: | dense hypocellular fibrous tissue resembling tendon with lacuna formation |
slight shortening of affected leg
Location: | insertion of pes anserinus (= tendinous insertion of gracilis, sartorius, semitendinosus muscles) distal to proximal tibial physis; unilateral involvement |
unilateral tibia vara well-defined elliptic obliquely oriented lucent defect in medial tibial metadiaphyseal cortex sclerosis along lateral border of lesion absence of bone margin superomedially
Prognosis: | resolution in 1 4 years |
DDx: | (1) Unilateral Blount disease (typically bilateral in infants, varus angulation of upper tibia, decreased height of medial tibial metaphysis, irregular physis) (2) Chondromyxoid fibroma, eosinophilic granuloma, osteoid osteoma, osteoma, fibroma, chondroma (not associated with tibia vara, soft-tissue mass) |
Fracture
= soft-tissue injury in which there is a break in the continuity of bone or cartilage
General description:
OPEN / [CLOSED]
open Fx = communication between fractured bone + skin [COMPLETE]/INCOMPLETE
complete Fx = all cortical surfaces disrupted incomplete Fx = partial separation of bone greenstick Fx = break of one cortical margin only with intact periosteum due to tension on soft growing bone buckle / torus Fx = buckling of cortex due to compression bowing Fx = plastic deformity of thin long bone (clavicle, ulna, fibula) lead-pipe Fx = combination of greenstick + torus Fx SIMPLE / COMMINUTED
simple Fx = noncomminuted comminuted Fx = >2 fragments segmental Fx = isolated segment of shaft butterfly fragment = V-shaped fragment not completely circumscribed by cortex DIRECTION OF FRACTURE LINE in relation to long axis of bone: transverse, oblique, oblique-transverse, spiral
Special terminology:
avulsion Fx | = | fragment pulled off by tendon / ligament from parent bone |
transchondral Fx | = | cartilaginous surface involved |
chondral Fx | = | cartilage alone involved |
osteochondral Fx | = | cartilage + subjacent bone involved |
Description of anatomic positional changes:
= change in position of distal fracture fragment in relation to proximal fracture fragment
LENGTH
= longitudinal change of fragments
distraction = increase from original anatomic length
shortening = decrease from original anatomic length
impacted = fragments driven into each other
overriding = also includes latitudinal changes
overlapping = bayonet apposition
DISPLACEMENT
= latitudinal change of anatomic axis:
undisplaced
anterior, posterior, medial / ulnar, lateral / radial
ANGULATION / TILT
= long axes of fragments intersect at the fracture apex:
medial / lateral, ventral / dorsal
varus = angular deviation of distal fragment toward midline on frontal projection
valgus = angular deviation of distal fragment away from midline on frontal projection
eg, ventral angulation of fracture apex
eg, in anatomic / near anatomic alignment
ROTATION
Difficult to detect radiographically! differences in diameters of apposing fragments mismatch of fracture line geometry internal / external rotation
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NUC:
Typical time course:
Acute phase (3 4 weeks)
abnormal in 80% <24 hours, in 95% <72 hours
Elderly patients show delayed appearance of positive scan broad area of increased tracer uptake (wider than fracture line)
Subacute phase (2 3 months) = time of most intense tracer accumulation
more focal increased tracer uptake corresponding to fracture line
Chronic phase (1 2 years)
slow decline in tracer accumulation in 65% normal after 1 year; >95% normal after 3 years
Return to normal:
Non weight-bearing bone returns to normal more quickly than weight-bearing bone Rib fractures return to normal most rapidly Complicated fractures with orthopedic fixation devices take longest to return to normal
Simple fractures: 90% normal by 2 years
Open reduction / fixation: <50% normal by 3 years
Delayed union: slower than normal for type of fracture
Nonunion: persistent intense uptake in 80%
Complicated union (true pseudarthrosis, soft-tissue interposition, impaired blood supply, presence of infection)
intense uptake at fracture ends decreased uptake at fracture site
Vertebral compression fractures: 60% normal by 1 year; 90% by 2 years; 97% by 3 years
Pathologic Fracture
= fracture at site of preexisting osseous abnormality
Cause: | tumor, osteoporosis, infection, metabolic disorder |
Stress Fracture
= fractures produced as a result of repetitive prolonged muscular action on bone that has not accommodated itself to such action
Insufficiency Stress Fracture
= normal physiologic stress applied to bone with abnormal elastic resistance / deficient mineralization
Cause:
Osteoporosis
Renal osteodystrophy
Osteomalacia / rickets
Hyperparathyroidism
Radiation therapy
Rheumatoid arthritis
Paget disease
Fibrous dysplasia
Osteogenesis imperfecta
Osteopetrosis
Prolonged corticosteroid treatment
Tumor treatment with ifosfamide, methotrexate
Location: | thoracic vertebra, sacrum, pubic bone, ilium, lower extremity (calcaneus, tibia, fibula) |
Fracture orientation: | perpendicular to long axis of bone |
Plain film / CT (1 2 weeks after onset of fracture):
cortical lucency (due to disruption) periosteal new bone formation medullary sclerosis (endosteal callus formation)
MR:
zone of low signal intensity on T1WI + variable intensity on T2WI (= discrete fracture line) surrounded by diffuse marrow edema (hypointense on T1WI + hyperintense) hyperintense components of circumferential periosteal reaction + early callus + surrounding edema adjacent to bone on T2WI with enhancement after IV Gd-chelate (DDx: osteomyelitis with more eccentric involvement)
NUC (bone scan):
increased abnormal uptake
Pelvic Insufficiency Stress Fracture
severe pain in lower back + sacroiliac joints; radiates to buttocks, hips, groin, legs; worsens with weight bearing
walking ability impaired
Incidence: | 1.8 5% of women >55 years |
Predisposed: | postmenopausal women |
Location: | sacral ala, parasymphyseal region of os pubis, pubic rami, supraacetabular region, iliac blades, superomedial portion of ilium |
Types:
occult fracture:
Site: sacrum > supraacetabulum, ilium sclerotic band, cortical disruption, fracture line Often obscured by overlying bowel gas + osteopenia! Types of Fractures
Type Bone Quality Load Traumatic normal single large Fatigue (stress) normal repetitive Insufficiency (stress) abnormal (metabolic) minimal Pathologic abnormal (tumor) minimal Fatigue (Stress) and insufficiency fracture of Hip
aggressive fracture:
Site: parasymphysis, pubic rami exuberant callus formation, osteolysis + fragments (with prolonged or delayed healing / chronic nonunion)
CAVE: fracture may be misdiagnosed as neoplasm; interpretation also histologically difficult
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NUC:
butterfly / H-shaped ( Honda sign ) / asymmetric incomplete H-shaped pattern of sacral uptake pelvic outlet view for parasymphyseal fx
CT and MR (most accurate modalities):
sclerotic band, linear fracture line, cortical disruption, fragmentation, displacement bone marrow edema Excludes bone destruction + soft-tissue masses!
Prognosis: | healing in 12 30 months |
Femoral Insufficiency Fracture
Site: | subcapital |
subtle femoral neck angulation trabecular angulation subcapital impaction line
Fatigue Stress Fracture
= normal bone subjected to repetitive stresses (none of which is singularly capable of producing a fracture) leading to mechanical failure over time
Risk factors: new / different / rigorous repetitive activity; female sex; increased age; Caucasian race; low bone mineral density; low calcium intake; fluoride treatment for osteoporosis; condition resulting in altered gait activity-related pain abating with rest
constant pain with continued activity
@ Spine
Clay shoveler's fracture: spinous process of lower cervical / upper thoracic spine
Spondylolysis = pars interarticularis of lumbar vertebrae: ballet, lifting heavy objects, scrubbing floors
Ribs: carrying heavy pack, golf, coughing
@ Upper extremity
Clavicle: postoperative (radical neck dissection)
Coracoid process of scapula: trap shooting
Coronoid process of ulna: pitching ball, throwing javelin, pitchfork work, propelling wheelchairs
Distal shaft of humerus: throwing ball
Hook of hamate: swinging golf club / tennis racquet / baseball bat
@ Pelvis
Obturator ring of pelvis: stooping, bowling, gymnastics
Site: superior / inferior pubic ramus Sacrum (<2%): long-distance runner, military recruits
Site: unilateral (? due to leg length discrepancy)
@ Lower extremity
Femoral neck: ballet, long-distance running
Site: medial femoral neck subtle lucency / sclerosis (= acute fracture) lucent line surrounded by sclerosis (= subacute fracture)
Femoral shaft: ballet, marching, long-distance running, gymnastics
Patella: hurdling
Tibial shaft: ballet, jogging
Fibula: long-distance running, jumping, parachuting
@ Foot (in order of frequency):
Second metatarsal: marching, stomping on ground, prolonged standing, ballet, postoperative bunionectomy
Calcaneus: jumping, parachuting, prolonged standing, recent immobilization
vertical / oblique fracture orientation anterior to tuberosity
Navicular: stomping on ground, marching, prolonged standing, ballet
vertically oriented fracture in midbody Midfoot fractures are difficult to diagnose by conventional radiography; CT + MRI are often helpful
Sesamoids of metatarsal: prolonged standing
X-RAY (15% sensitive in early fractures, increasing to 50% on follow-up):
cancellous (trabecular) bone (notoriously difficult to detect)
subtle blurring of trabecular margins faint sclerotic radiopaque area of peritrabecular callus (50% change in bone density needed) sclerotic band (due to trabecular compression + callus formation) usually perpendicular to cortex
compact (cortical) bone
gray cortex sign = subtle ill definition of cortex intracortical radiolucent striations (early) solid thick lamellar periosteal new bone formation endosteal thickening (later)
Follow-up radiography after 2 3 weeks of conservative therapy Salter-Harris Classification of Epiphyseal Plate injury
Rang and Ogden's additions to Salter-Harris Classification
P.84
NUC ( gold standard = almost 100% sensitive):
abnormal uptake within 6 72 hours of injury (prior to radiographic abnormality) stress reaction = focus of subtly increased uptake focal fusiform area of intense cortical uptake abnormal uptake persists for months
MR (very sensitive modality; fat saturation technique most sensitive as it detects an increase in water content of medullary edema / hemorrhage):
diminished marrow signal intensity on T1WI of fracture line increased marrow signal intensity on T2WI (edema may obscure the fracture line), resolves within 6 months in 90% low-intensity band contiguous with cortex on T2WI = fracture line of more advanced lesion
CT (least sensitive modality):
helpful in: | longitudinal stress fracture of tibia; in confusing pediatric stress fracture (to detect endosteal bone formation) |
DDx:
Shin splints (activity not increased in angiographic / blood-pool phase)
long linear uptake on posteromedial (soleus muscle) / anterolateral (tibialis anterior muscle) tibial cortex on delayed images (from stress to periosteum at muscle insertion site)
Osteoid osteoma (eccentric, nidus, solid periosteal reaction, night pain)
Chronic sclerosing osteomyelitis (dense, sclerotic, involving entire circumference, little change on serial radiographs)
Osteomalacia (bowed long bones, looser zones, gross fractures, demineralization)
Osteogenic sarcoma (metaphyseal, aggressive periosteal reaction)
Ewing tumor (lytic destructive appearance with soft-tissue component, little change on serial radiographs)
Epiphyseal Plate Injury
Prevalence: | 6 18 30% of bone injuries in children <16 years of age |
Peak age: | 12 years |
Location: | distal radius (28%), phalanges of hand (26%), distal tibia (10%), distal phalanges of foot (7%), distal humerus (7%), distal ulna (4%), proximal radius (4%), metacarpals (4%), distal fibula (3%) |
Mechanism: | 80% shearing force; 20% compression |
Resistance to trauma: | ligament > bone > physis (hypertrophic zone most vulnerable) |
Salter-Harris classification (considering probability of growth disturbance)
[Robert Bruce Salter (1924 ) and W. Robert Harris (1922 ), orthopedic surgeons in Toronto, Canada]
Prognosis is worse in lower extremities (ankle + knee) irrespective of Salter-Harris type!
mnemonic: | SALTR |
Slip of physis | = | type 1 |
Above physis | = | type 2 |
Lower than physis | = | type 3 |
Through physis | = | type 4 |
Rammed physis | = | type 5 |
P.85
Salter Type 1 (6 8.5%)
= slip of epiphysis due to shearing force separating epiphysis from physis
Line of cleavage: confined to physis Location: most commonly in phalanges, distal radius (includes: apophyseal avulsion, slipped capital femoral epiphysis) displacement of epiphyseal ossification center Prognosis: favorable irrespective of location
Salter Type 2 (73 75%)
= shearing force splits growth plate
Line of fracture: | through physis + extending through margin of metaphysis separating a triangular metaphyseal fragment (= corner sign ) |
Location: | distal radius (33 50%), distal tibia + fibula, phalanges |
Prognosis: | good, may result in minimal shortening |
Salter Type 3 (6.5 8%)
= intraarticular fracture, often occurring after partial closure of physis
Line of fracture: vertically / obliquely through epiphysis + extending horizontally to periphery of physis Location: distal tibia, distal phalanx, rarely distal femur epiphysis split vertically Prognosis: fair (imprecise reduction leads to alteration in linearity of articular plane)
Salter Type 4 (10 12%)
Location: | lateral condyle of humerus, distal tibia |
fracture involves metaphysis + physis + epiphysis Prognosis: guarded (may result in deformity + angulation)
Salter Type 5 (<1%)
= crush injury with injury to vascular supply
Location: distal femur, proximal tibia, distal tibia Often associated with: fracture of adjacent shaft no immediate radiographic finding shortening of bone + cone epiphysis / angular deformity on follow-up Prognosis: poor (impairment of growth in 100%)
Triplane Fracture (6%)
Location: | distal tibia, lateral condyle of distal humerus |
vertical fracture of epiphysis + horizontal cleavage plane within physis + oblique fracture of adjacent metaphysis MR:
focal dark linear area (= line of cleavage) within bright physis on gradient echo images (GRE)
Cx: (1) progressive angular deformity from segmental arrest of germinal zone growth with formation of a bone bridge across physis = bone bar (2) limb length discrepancy from total cessation of growth
(3) articular incongruity from disruption of articular surface
(4) Bone infarction in metaphysis / epiphysis
Apophyseal Injury
Mechanism: | excessive avulsive force |
Physis under secondary ossification center is weakest part! At risk: young athletes: hurdlers, sprinters, cheerleaders (repetitive to and fro adduction / abduction + flexion / extension) Age: children > adults Avulsion injury of lesser trochanter in adults suggests underlying malignant disease
pain, point tenderness, swelling
irregularity at site of avulsion displaced pieces of bone of variable size: crescentic ossific opacity if viewed on tangent very subtle disk-shaped opacity if seen en face
abnormal foci of heterotopic ossification (later) prominent bone formation in chronic avulsion injury from overuse with repeated microtraumas
DDx of healing acute injury: | osteomyelitis, Ewing sarcoma |
Hand Fracture
Bennett Fracture
[Edward Hallaran Bennett (1837 1907), surgeon in Dublin, Ireland]
Mechanism: forced abduction of thumb intraarticular fracture-dislocation of base of 1st metacarpal small fragment of 1st metacarpal continues to articulate with trapezium lateral retraction of 1st metacarpal shaft by abductor pollicis longus
Rx: | anatomic reduction important, difficult to keep in anatomic alignment |
Cx: | pseudarthrosis |
Boxer's Fracture
Mechanism: | direct blow with clenched fist |
transverse fracture of distal metacarpal (usually 5th)
Gamekeeper's Thumb
= SKIER'S THUMB (originally described as chronic lesion in hunters strangling rabbits)
P.86
Incidence: | 6% of all skiing injuries; 50% of skiing injuries to the hand |
Mechanism: | violent abduction of thumb with injury to ulnar collateral ligament (UCL) in 1st MCP (faulty handling of ski pole) |
Apophyseal Avulsion Injuries
Location | Muscle Origin / Insertion |
---|---|
Anterior superior iliac spine | sartorius muscle + tensor fasciae latae m. |
Anterior inferior iliac spine | rectus femoris muscle |
Lesser trochanter | iliopsoas muscle |
Ischial tuberosity | hamstrings |
Greater trochanter | gluteus medius + minimus, internal obturator, gemellus, piriformis |
Iliac crest | abdominal musculature |
Symphysis pubis + inferior pubic ramus | long + short adductors, gracilis |
No Caption Available. |
disruption of ulnar collateral ligament of 1st MCP joint, usually occurring distally near insertion on proximal phalanx radial stress examination necessary to document ligamentous disruption displacement of UCL superficial to aponeurosis of adductor pollicis (= Stener lesion) [torn end of UCL may be marked by avulsed bone fragment]
Navicular Fracture
= SCAPHOID FRACTURE
Most frequent (90%) of all carpal bones fractures! Mechanism: fall on dorsiflexed outstretched hand pain + tenderness at anatomic snuff box
Radiographic misses: 25 33 65% N.B.: If initial radiograph negative, reexamine in 2 + 6 weeks after treatment with short-arm spica cast! MR: high sensitivity
Bone scan: up to 100% sensitive, 93% PPV after 2 3 days Prognosis: dependent on following factors fracture displacement = >1 mm offset / angulation / rotation of fragments (less favorable) location (blood supply derived from distal part): distal 1/3 (10%) = usually fragments reunite
middle 1/3 (70%) = failure to reunite in 30%
proximal 1/3 (20%) = failure to reunite in 90%
orientation of fracture transverse / horizontal oblique = relatively stable
vertical oblique (less common) = unstable
Good prognosis with distal fracture + no displacement + no ligamentous injury! Less favorable prognosis with displaced / comminuted fracture + proximal pole fracture!
Cx: avascular necrosis of proximal fragment
Rolando Fracture
[Silvio Rolando (? 1931?), surgeon in Genoa, Italy]
comminuted Y- / T-shaped intraarticular fracture-dislocation through base of thumb metacarpal
Prognosis: | worse than Bennett's fracture (difficult to reduce) |
No Caption Available. |
Forearm Fracture
Barton Fracture
[John Rhea Barton (1794 1871), orthopedic surgeon at Pennsylvania Hospital, Philadelphia]
Mechanism: fall on outstretched hand intraarticular oblique fracture of ventral / dorsal lip of distal radius carpus dislocates with distal fragment up and back on radius
P.87
Chauffeur Fracture
= HUTCHINSON FRACTURE = BACKFIRE FRACTURE = LORRY DRIVER FRACTURE
[Jonathan Hutchinson (1828 1913), British surgeon]
= name derived from direct trauma to radial side of wrist sustained from recoil of crank used in era of hand cranking to start automobiles
Mechanism: acute dorsiflexion + abduction of hand triangular fracture of radial styloid process
Colles Fracture
[Abraham Colles (1773 1843), surgeon in Dublin, Ireland]
= POUTEAU FRACTURE (term used in France)
[Claude Pouteau (1725 1775), surgeon in Lyon, France]
Most common fracture of forearm!
Mechanism: | fall on outstretched hand |
nonarticular radial fracture in distal 2 cm dorsal displacement of distal fragment + volar angulation of fracture apex ulnar styloid fracture silver-fork deformity Cx: posttraumatic arthritis Rx: anatomic reduction important Significant postreduction deformity:
Residual positive ulnar variance >5 mm indicates unsatisfactory outcome in 40%
Dorsal angulation of palmar tilt >15 decreases grip strength + endurance in >50%
Essex-Lopresti Fracture
[Peter Gordon Essex-Lopresti (1918 1951), surgeon at Birmingham Accident Center, England]
comminuted displaced radial head fracture dislocation of distal radioulnar joint
Galeazzi Fracture
[Ricardo Galeazzi (1866 1952), orthopedic surgeon in Italy]
= PIEDMONT FRACTURE
Mechanism: | fall on outstretched hand with elbow flexed |
Anterior Humeral Line and Elbow fat Pads |
radial shaft fracture (most commonly) at junction of distal to middle third with dorsal angulation subluxation / dislocation of distal radioulnar joint ulnar plus variance (= radial shortening) of >10 mm implies complete disruption of interosseous membrane = complete instability of radioulnar joint Cx: (1) High incidence of nonunion, delayed union, malunion (unstable fracture) (2) Limitation of pronation / supination
Monteggia-type Fracture
= fracture of ulnar shaft + dislocation of radial head
Bado Classification:
[Jose Luis Bado (1903 1977), orthopedic surgeon from Uruguay]
Type I = classic Monteggia fracture
[Giovanni Battista Monteggia (1762 1815), Italian surgeon]
Mechanism: direct blow to the forearm anteriorly angulated proximal ulnar fracture anterior dislocation of radial head may have associated wrist injury Cx: nonunion, limitation of motion at elbow, nerve abnormalities
Type II = reverse Monteggia fracture
radial head displaced posteriorly / posterolaterally dorsally angulated proximal ulnar fracture
Type III
anterior / anterolateral dislocation of radial head ulnar metaphyseal fracture
Type IV
anterior displacement of radial head fracture of proximal third of radius + ulna at the same level
Smith Fracture
= REVERSE COLLES FRACTURE = REVERSE BARTON FRACTURE = GOYRAND FRACTURE (term used in France)
[Robert William Smith (1807 1873), succeeding Colles as professor of surgery at Trinity College in Dublin, Ireland]
Mechanism: | hyperflexion with fall on back of hand |
nonarticular distal radial fracture ventral displacement of fragment radial deviation of hand garden spade deformity Cx: altered function of carpus
Elbow Fracture
common among children 2 14 years of age
@ Soft-tissue
displacement of anterior + posterior fat pads (= elbow joint effusion with supracondylar / lateral condylar / proximal ulnar fractures)
supinator fat pad (= fracture of proximal radius) focal edema medially (= medial epicondyle fx) / laterally (= lateral condyle fx)
@ Humerus (80%)
Supracondylar fracture (55%)
Mechanism: hyperextension with vertical stress transverse fracture line distal fragment posteriorly displaced / tilted anterior humeral line intersecting anterior to posterior third of capitellum (on lateral x-ray) Fractures of the Acetabulum
P.88
Lateral condylar fracture (20%)
Mechanism: hyperextension with varus stress fracture line between lateral condyle + trochlea / through capitellum
Medial epicondylar fracture (5%)
Mechanism: hyperextension with valgus stress avulsion of medial epicondyle (by flexor muscles of forearm) may become trapped in joint space (after reduction of concomitant elbow dislocation)
@ Radius (10%)
Mechanism: hyperextension with valgus stress Salter-Harris type II / IV fracture transverse metaphyseal / radial neck fracture
Mechanism: hyperextension with varus stress dislocation as part of Monteggia fracture (from rupture of annular ligament)
@ Ulna (10%)
longitudinal linear fracture through proximal shaft Mechanism: hyperextension with vertical stress transverse fracture through olecranon Mechanism: hyperextension with valgus / varus stress; blow to posterior elbow in flexed position coronoid process avulsion Mechanism: hyperextension-rotation associated with forceful contraction of brachial m.
Rib Fracture
Associated with: | pneumothorax, hemothorax, lung contusion / laceration |
@ 1st rib
Indicates substantial trauma (due to protected location) Cause: acute trauma / fatigue fracture (from carrying a heavy back pack) Associated with: aortic / great vessel injury; thoracic vertebral fracture; scapular fracture
@ Lower ribs
Associated with: injury to upper abdominal organs / diaphragm
Malgaigne Fracture |
P.89
Flail Chest
= fracture of >4 contiguous ribs
paradoxic motion of chest wall with respiration
respiratory failure
Cough Fracture
Location: | 4 9th rib in anterior axillary line |
Pelvic Fracture
Unstable pelvic fractures:
anterior compression
Bilateral vertical pubic rami fractures
Symphysis + sacroiliac joint diastasis
lateral compression
Malgaigne (ipsilateral anterior + posterior fx)
Bucket-handle (contralateral anterior + posterior fx)
vertical shear
Superior displacement of pelvis
Acetabular Fracture
Anatomy & Function:
most important portion of acetabulum is roof / dome;
weight-bearing surface for entire lower limb is derived + supported by 2 columns which are oriented in an inverted Y and join above the acetabular roof at an angle of 60 :
anterior iliopubic column of acetabulum
posterior ilioischial column of acetabulum
Classification (Judet and Letournel):
Elementary fractures
Posterior wall 27% Anterior column 5% Transverse 9% Posterior column 4% Anterior wall 2% Associated fractures
Transverse + posterior wall 27% Both columns 19% T-shaped 6% Anterior wall + posterior hemitransverse 5% Posterior column + posterior wall 3%
Duverney Fracture |
Posterior wall (lip / rim) fracture (27%)
Mechanism: | indirect force transmitted through length of femur with flexed hip joint (knee strikes dashboard) |
Associated with: | posterior dislocation of femur |
Transverse fracture (9%)
N.B.: | most difficult to diagnose + comprehend |
transects both the iliopubic + ilioischial columns with fracture line in an anteroposterior direction
Anterior column fracture (5%)
Mechanism: | blow to greater trochanter with hip externally rotated |
Associated with: | posterior column / transverse fracture |
fracture begins between anterior iliac spines + traverses the acetabular fossa + ends in the ischiopubic ramus
Posterior column fracture (4%)
Mechanism: | indirect force transmitted through length of femur with hip abducted |
Associated with: | posterior dislocation of femur + sciatic nerve injury |
fracture begins at greater sciatic notch + traverses the posterior aspect of acetabular fossa + ends in the ischiopubic ramus
Anterior wall fracture (2%)
Mechanism: | force transmitted through greater trochanter |
Associated with: | posterior dislocation of femur + sciatic nerve injury |
fracture begins on anterior rim of acetabulum + emerges on lateral aspect of superior pubic ramus
Malgaigne Fracture
[Joseph Fran ois Malgaigne (1806 1865), French surgical historian, published first comprehensive book on fractures]
= fracture-dislocation of one side of the pelvis with anterior + posterior disruption of pelvic ring
P.90
Tibial Plateau Fractures |
Mechanism: | direct trauma |
shortening of involved extremity
vertical fractures through one side of pelvic ring superior to acetabulum (ilium)
inferior to acetabulum (pubic rami)
sacroiliac dislocation / fracture
lateral unstable fragment contains acetabulum
Bucket Handle Fracture
double vertical fracture through superior and inferior pubic rami + sacroiliac joint dislocation on contralateral side
Duverney Fracture
[Joseph Guichard Duverney (1648 1730), French surgeon]
isolated fracture of iliac wing
Knee Fracture
Segond Fracture
[Paul Ferdinand Segond (1851 1912), surgeon in chief at Salp tri re in Paris, France]
Mechanism: external rotation + varus stress causing excessive tension on the lateral capsular ligament Associated with: lesion of anterior cruciate ligament (75 100%), meniscal tear (67%) anterolateral instability of the knee
small cortical avulsion fracture of proximal lateral tibial rim just distal to lateral plateau
Tibial Plateau Fracture (Schatzker classification)
Mechanism: | valgus force ( bumper / fender fracture from lateral force of automobile against a pedestrian's fixed knee) / compression force often in extension |
Type I | = | wedge-shaped pure cleavage fracture | 6% |
Type II | = | combined cleavage + median compression fracture | 25% |
Type III | = | pure compression fracture | 36% |
Type IV | = | medial plateau fracture with a split /depressed comminution | 10% |
Type V = | bicondylar fracture, often withinverted Y appearance | 3% | |
Type VI | = | transverse / oblique fracture withseparation of metaphysis fromdiaphysis | 20% |
Lateral plateau fractures (type I III) are most common! Fractures of medial plateau are associated with greater violence and higher percentage of associated injuries!
Foot Fracture
Ankle Fracture
Incidence: | ankle injuries account for 10% of all emergency room visits; 85% of all ankle sprains involve lateral ligaments |
Ligamentous connections at ankle:
binding tibia + fibula
anterior inferior tibiofibular ligament (= tibiofibular syndesmosis)
posterior inferior tibiofibular ligament
transverse tibiofibular ligament
interosseous membrane
lateral malleolus
85% of all ankle sprains involve these ligaments:
anterior talofibular ligament
posterior talofibular ligament
calcaneofibular ligament
medial malleolus = deltoid ligament with
navicular portion
sustentaculum portion
talar portion
Lateral Malleolar Fractures
Weber Type A
[Bernhard Georg Weber (1929 ), orthopedic surgeon in St. Gall, Switzerland]
= SUPINATION-ADDUCTION INJURY = INVERSION-ADDUCTION INJURY
Mechanism:
avulsive forces affect lateral ankle structures
impactive forces secondary to talar shift stress medial structures
sprain / rupture of lateral collateral ligament Anterior tibiofibular ligament ruptures alone in 66% Injury of all 3 lateral ligaments in 20% P.91
Prognosis: chronic lateral ankle instability in 10 20% transverse avulsion of malleolus sparing tibiofibular ligaments oblique fracture of medial malleolus posterior tibial lip fracture
Weber Type B
= SUPINATION-ABDUCTION INJURY = EVERSION-EXTERNAL ROTATION
Mechanism:
avulsive forces on medial structures
impacting forces on lateral structures (talar impact)
oblique / spiral fracture of lateral malleolus starting at level of joint space extending proximally lateral subluxation of talus partial disruption of tibiofibular ligament sprain / rupture / avulsion of deltoid ligament transverse fracture of medial malleolus
Dupuytren Fracture
[Guillaume Dupuytren (1777 1835), French surgeon]
fracture of distal fibula above a disrupted tibiofibular ligament + disruption of deltoid ligament
LeFort Fracture of Ankle
[Leon Clement LeFort (1829 1893), French surgeon]
vertical fracture of anterior medial portion of distal fibula avulsion of anterior tibiofibular ligament
Ankle Fractures |
Maisonneuve Fracture |
Weber Type C
= PRONATION-EXTERNAL ROTATION = EVERSION + EXTERNAL ROTATION
fibular fracture higher than ankle joint (Maisonneuve fracture if around knee) deltoid ligament tear medial malleolar fracture tear of tibiofibular ligament / avulsion of anterior tubercle (Tillaux-Chaput) / avulsion of posterior tubercle (Volkmann) tear of interosseous membrane = lateral instability
Tillaux Fracture
[Paul Jules Tillaux (1834 1904), French surgeon and anatomist]
avulsion injury of anterior tibial tubercle at attachment of distal anterior tibiofibular ligament
Maisonneuve Fracture
[Jacques Gilles Maisonneuve (1809 1897), student of Dupuytren]
tear of distal tibiofibular syndesmosis + interosseous membrane spiral fracture of upper third of fibula associated fracture of medial malleolus / rupture of deep deltoid ligament
Chopart Fracture
[Fran ois Chopart (1743 1795), surgeon in Paris, France]
fracture-dislocation through midtarsal / Chopart (calcaneocuboid + talonavicular) joint commonly associated with fractures of the bones abutting the joint
Jones Fracture
[Robert Jones (1857 1933), British orthopedic surgeon and pioneer in radiology described fracture in Ann Surg 1902]
Mechanism: adduction of forefoot with ankle in plantar flexion transverse fracture at base of 5th metatarsal bone at junction of diaphysis and metaphysis (>1.5 cm distal to proximal tip of metatarsal tuberosity) Cx: delayed union / nonunion (poor blood supply)
P.92
Peroneus Brevis Avulsion Fracture
= METATARSAL 5 TUBEROSITY FRACTURE
Most common fracture of the proximal 5th metatarsal bone Mechanism: plantar flexion + inversion (stepping off a curb) transverse avulsion fracture of base of 5th metatarsal bone Location: proximal to metatarsal tuberosity (insertion of peroneus brevis tendon); usually extraarticular DDx: Jones fracture (slightly different location)
Lisfranc Fracture
[Jacques Lisfranc De Saint Martin (1790 1847), surgeon in Napoleon's army]
Mechanism: metatarsal heads fixed and hindfoot forced plantarward and into rotation fracture-dislocation / fracture-subluxation of tarsometatarsal joints (typically 2 through 5) lateral displacement of metatarsals
Shepherd Fracture
[Francis J. Shepherd (1851 1929), demonstrator in anatomy at McGill University in Montreal, Canada]
fracture of lateral tubercle of posterior process of talus DDx: os trigonum
Calcaneal Fracture
Incidence: | most commonly fractured tarsal bone; 60% of all tarsal fractures; 2% of all fractures in the body; commonly bilateral |
Mechanism: | fall from heights |
May be associated with: | lumbar vertebral fracture |
Age: | 95% in adults, 5% in children |
adulthood: | intraarticular (75%), extraarticular (25%) |
childhood: | extraarticular (63 92%) |
No Caption Available. |
Classification:
extraarticular fracture of calcaneal tuberosity:beak type, vertical, horizontal, medial avulsion
intraarticular fracture
subtalar joint involvement: undisplaced, displaced, comminuted
calcaneocuboid joint involvement
apex of lateral talar process does not point to crucial angle of Gissane Boehler angle decreased below 28 40
Frostbite
Cause: | (1) cellular injury + necrosis from freezing process (2) cessation of circulation secondary to cellular aggregates + thrombi forming as a result of exposure to low temperatures below 13 C (usually cold air) |
firm white numb areas in cutis (separation of epidermal-dermal interface)
Location: | feet, hands (thumb commonly spared due to protection by clenched fist) |
Early changes:
soft-tissue swelling + loss of tissue at tips of digits
CHILD
fragmentation / premature fusion / destruction of distal phalangeal epiphyses secondary infection, articular cartilage injury, joint space narrowing, sclerosis, osteophytosis of DIP shortening + deviation / deformity of fingers
ADULT
osteoporosis (4 10 weeks after injury) periostitis acromutilation (secondary to osteomyelitis + surgical removal) + tuftal resorption (result of soft-tissue loss) small round punched-out areas near edge of joint interphalangeal joint abnormalities (simulating osteoarthritis) calcification / ossification of pinna
Angio:
vasospasm, stenosis, occlusion proliferation of arterial + venous collaterals (in recovery phase)
Bone scintigraphy:
persistent absence of uptake (= lack of vascular perfusion) indicates nonviable tissue
Rx: | selective angiography with intraarterial reserpine |
Ganglion
Ganglion cyst | = | mucin-containing cyst arising from tendon sheath / joint capsule / bursa / subchondral bone lined by flat spindle-shaped cells |
Synovial cyst | = | cyst continuous with joint capsule lined by synovial cells (term is used by some synonymously with ganglion) |
Soft-tissue Ganglion
= cystic tumorlike lesion usually attached to a tendon sheath
P.93
Origin: | synovial herniation / coalescence of smaller cysts formed by myxomatous degeneration of periarticular connective tissue |
asymptomatic / pain
uni- / multilocular swelling
Location: hand, wrist, foot (over dorsum) Site: arise from tendon, muscle, semilunar cartilage soft-tissue mass with surface bone resorption periosteal new-bone formation arthrography may demonstrate communication with joint / tendon sheath internal septations, lobulated configuration hypointense relative to muscle on T1WI / hyperintense content (protein, hemorrhage) hyperintense relative to fat on T2WI no enhancement
Prognosis: | may resolve spontaneously |
Rx: | steroid injection may improve symptomatology |
DDx on MRI: | myxoid lipoma, highly necrotic tumor |
Intraosseous Ganglion
= benign subchondral radiolucent lesion WITHOUT degenerative arthritis
mild localized pain (4% of patients with unexplained wrist pain)
Age: middle age Origin: (1) mucoid degeneration of intraosseous connective tissue perhaps due to trauma / ischemia (2) penetration of juxtaosseous soft-tissue ganglion (= synovial herniation) into underlying bone (occasionally)
Path: uni- / multilocular cyst surrounded by fibrous lining, containing gelatinous material Location: epiphysis of long bone (medial malleolus, femoral head, proximal tibia, carpal bones) / subarticular flat bone (acetabulum) well-demarcated solitary 0.6 6 cm lytic lesion sclerotic margin NO communication with joint increased radiotracer uptake on bone scintigraphy (in 10%) DDx: posttraumatic / degenerative cyst
Periosteal Ganglion
= cystic structure with viscid / mucinous contents
Incidence: 11 cases in literature Age: 39 50 years; M > F swelling, mild tenderness
Location: long tubular bones of lower extremity cortical erosion / scalloping / reactive bone formation NO intraosseous component (endosteal surface intact) CT:
well-defined soft-tissue mass adjacent to bone cortex with fluid contents
MR:
homogeneous isointense signal to muscle on T1WI homogeneous hyperintense signal to fat on T2WI NO internal septations (DDx to soft-tissue ganglion)
DDx: periosteal chondroma without matrix calcification, cortical desmoid, subperiosteal aneurysmal bone cyst, acute subperiosteal hematoma (history of trauma / blood dyscrasia), subperiosteal abscess (involvement of adjacent bone marrow) Rx: surgical excision (local recurrence possible)
Gardner Syndrome
= autosomal dominant syndrome characterized by
osteomas
soft-tissue tumors
colonic polyps
Location of osteomas: paranasal sinuses; outer table of skull (frequent); mandible (at angle) endosteal cortical thickening / osteomas in any bone may have solid periosteal cortical thickening osteomas / exostoses may protrude from periosteal surface wavy cortical thickening of superior aspect of ribs polyps: colon, stomach, duodenum, ampulla of Vater, small intestine Cx: high incidence of carcinoma of duodenum / ampulla of Vater
Gaucher Disease
= rare autosomal recessive / dominant (in a few) lipid storage disorder; the most common lysosomal storage disorder;
M = F
Incidence: 1:50,000 100,000 (general population); 1:500 1,000 (in Ashkenazi Jews) Etiology: deficiency of lysosomal hydrolase acid -glycosidase (= beta-glucocerebrosidase) leads to accumulation of glucosylceramide (glucocerebroside) within macrophages of RES (liver, spleen, bone marrow, lung, lymph nodes) Histo: bone-marrow aspirate shows Gaucher cells (kerasin-laden histiocytes) of 20 100 m in diameter with a foamy wrinkled-paper appearance Clinical types:
Adult / chronic nonneuropathic form
= type 1 (most common form in USA)
Age of onset: 3rd 4th decade no clinical signs (most)
Prognosis: longest time of survival; pulmonary involvement / hepatic failure may lead to early death
Rapidly fatal infantile / acute neuropathic form
= type 2
Age of onset: 1 3 12 months early onset of significant hepatosplenomegaly
severe progressive neurologic symptoms: seizures, mental retardation, strabismus, spasticity
skeletal manifestations are rare Prognosis: fatal during first 2 years of life
Juvenile / subacute neuropathic form
= type 3 (rarest type)
Age of onset: 2 6 years variable hepatosplenomegaly
mild neurologic involvement: seizures
delayed onset of skeletal manifestations Prognosis: survival into adolescence
hepatosplenomegaly, impairment of liver function, ascites
elevated serum acid phosphatase
pancytopenia, anemia (chronic fatigue), leukopenia, thrombocytopenia (easy bruising, hypersplenism)
hemochromatosis (yellowish brown pigmentation of conjunctiva + skin)
dull bone pain (bone involvement in 75%)
Location: predominantly long tubular bones (distal femur), axial skeleton, hip, shoulder, pelvis; bilateral generalized osteopenia (decrease in trabecular bone density): striking cortical thinning + bone widening endosteal scalloping (due to marrow packing)
numerous sharply circumscribed lytic lesions resembling metastases / multiple myeloma (marrow replacement) periosteal reaction = cloaking Erlenmeyer flask deformity of distal femur + proximal tibia (2 to marrow infiltration) MOST CHARACTERISTIC weakening of subchondral bone: osteonecrosis (common, frequently of femoral head) degenerative arthritis
bone infarcts in long-bone metaphyses (most common in femoral + humeral heads): focal / serpentine areas of sclerosis bone-within-bone appearance
H-shaped / step-off / biconcave fish-mouth vertebrae (DDx: sickle cell disease) MR:
focal / diffuse replacement of adipocytes in bone marrow by Gaucher cells results in decreased marrow signal on T1WI + T2WI (marrow involvement follows the distribution of hematopoietic marrow in spine, pelvis, proximal femoral metaphysis; from proximal to distal in appendicular skeleton): epiphyses generally not involved
myelofibrotic marrow of low signal intensity on T1WI + T2WI (in long-standing disease)
@ Liver
hepatomegaly nonspecific fatty + cirrhotic changes focal lesions hypointense on T1WI + hyperintense to isointense on T2WI
@ Spleen
splenomegaly + lymphadenopathy multiple nodular lesions (= clusters of RES cells laden with glucosylceramide): hypodense without enhancement on CT hypoechoic / hyperechoic on US slightly hypointense to isointense on T1WI hypointense (Gaucher cells / fibrosis) or hyperintense (dilated sinusoids filled with blood around Gaucher cell infiltrates) on T2WI
splenic infarcts leading to fibrosis, especially in massively enlarged spleen
@ Lung
normal nonspecific diffuse reticulonodular / miliary infiltrates at lung bases (= infiltration with Gaucher cells)
P.94
Dx: | elevated serum activity of -glucocerebrosidase; genotyping |
Cx: | >90% have orthopedic complications at some time (1) Pathologic fractures + compression fractures of vertebrae (2) Avascular necrosis of femoral head, humeral head, wrist, ankle (common) (3) Osteomyelitis (increased incidence) (4) Myelosclerosis in long-standing disease (5) Repeated pulmonary infections (6) Cancer of hematopoietic origin (14.7-fold risk) |
Prognosis: | highly variable clinical course; strong relationship between splenic volume and disease severity |
Rx: | no cure; bone marrow transplantation; enzyme replacement therapy with Cerezyme |
DDx: | metastatic disease, multiple myeloma, leukemia, sickle-cell disease, fibrous dysplasia |
Giant Cell Reparative Granuloma
= GIANT CELL REACTION = GIANT CELL GRANULOMA
Cause: | ? reactive inflammatory process to trauma / infection (not a true neoplasm) |
Histo: | numerous giant cells in exuberant fibrous matrix arranged in clusters around foci of hemorrhage + commonly exhibiting osteoid formation (unusual in giant cell tumor); indistinguishable from brown tumor of HPT; cystic degeneration + ABC components distinctly uncommon |
Peak age: | 2nd + 3rd decade (ranging from childhood to 76 years); 74% <30 years of age; M:F = 1:1 |
May be associated with: | enchondromatosis, Goltz syndrome, fibrous dysplasia, Paget disease |
Location:
@ Gnathic (1 7% of all benign oral tumors):
gingiva + alveolar mucosa of mandible, maxilla
central type = in bone
peripheral type = in gingival soft tissue
M:F = 1:2
nonspecific pain + swelling (increasing during pregnancy)
expansile remodeling of bone with multilocular appearance thinned usually intact cortex DDx: indistinguishable from odontogenic cyst, ABC, ameloblastoma, odontogenic myxoma, odontogenic fibroma
@ Small bones of hand + feet (less common): phalanges of hand > metcarpals > metatarsals > carpal bones > tarsal bones > phalanges of foot
M:F = 1:1
nonspecific pain + swelling for months to years
Site: metaphysis extension into diaphysis; extension into epiphysis is UNCOMMON expansile lytic defect of 2 2.5 cm in diameter with internal trabeculations thinning of overlying cortex matrix mineralization may be seen (DDx to GCT) periosteal reaction is unusual (as in GCT) extension beyond cortex is unusual
@ Other locations (rare):
ethmoid sinus, sphenoid sinus, temporal bone, skull, spine, clavicle, tibia, humerus, ribs, femur
Cx: | pathologic fracture |
Prognosis: | may recur; no malignant transformation |
Rx: | curettage (22 50% recurrence rate) / local excision |
DDx: | (1) Enchondroma (same location, matrix calcification) (2) Aneurysmal bone cyst (rare in small bones of hand + feet, typically prior to epiphyseal closure) (3) Giant cell tumor (more aggressive appearance) (4) Infection (clinical) (5) Brown tumor of HPT (periosteal bone resorption, abnormal Ca + P levels) |
P.95
Giant Cell Tumor
= OSTEOCLASTOMA = OSTEOBLASTOCLASTOMA = TUMOR OF MYELOPLEXUS = MYELOID SARCOMA
= nonmineralized lytic eccentric metaepiphyseal lesion involving a long bone with extension to subarticular bone in the skeletally mature patient
Origin: | probably arise from zone of intense osteoclastic activity (of endochondral ossification) in skeletally immature patients |
Incidence: | 4 9.5% of all primary bone tumors; 18 23% of benign skeletal tumors; unusually high prevalence in China + southern India |
Path: | friable vascular stroma of numerous thin-walled capillaries with necrosis + hemorrhage + cyst formation (DDx: aneurysmal bone cyst without solid areas) |
Histo: | large number of multinucleated osteoclastic giant cells in a diffuse distribution in a background of mononuclear cells intermixed throughout a spindle cell stroma (DDx: giant cells characteristic of all reactive bone disease as in pigmented villonodular synovitis, benign chondroblastoma, nonosteogenic fibroma, chondromyxoid fibroma, fibrous dysplasia) |
Age: | peaks in 3rd decade; 1 3% < age 14; 80% between 20 and 50 years; 9 13% > age 50; M:F = 1:1.1 to 1:1.5 (in spine 1:2.5) |
May be associated with: | Paget disease (in 50 60% located in skull + facial bones) |
Staging:
Stage 1 | indolent radiographic + histologic appearance (10 15%) |
Stage 2 | more aggressive radiographic appearance with expansile remodeling (70 80%) |
Stage 3 | extension into adjacent soft tissues with histologically benign appearance (10 15%) |
pain at affected site (most common in 10% pathologic fracture)
local swelling + tenderness
weakness + sensory deficits (if in spine)
Location:
@ long bones (75 85 90%)
lower extremity (50 65% about knee):
distal end of femur (23 30%) > proximal end of tibia (20 25%) > proximal femur (4%) > distal tibia (2 5%) > proximal fibula (3 4%) > foot (1 2%)
RARE in patella (the largest sesamoid bone) + greater trochanter (epiphyseal equivalent)
upper extremity (away from elbow):
distal end of radius (10 12%) > proximal end of humerus (4 8%) > hand and wrist (1 5%)
@ flat bones (15%)
pelvis: sacrum near SIJ (4%), iliac bone (3%)
spine (3 6%): thoracic > cervical > lumbar spine (tumor frequency 2nd only to chordoma)
rib (anterior / posterior end)
skull (sphenoid bone)
Site: eccentric (42 93%) in metaphysis of long bones adjacent to ossified epiphyseal line; extension to within 1 cm of subarticular bone (84 99%) after fusion of epiphyseal plate (MOST TYPICAL) with possible transarticular spread The open epiphyseal plate acts as a barrier to tumor growth!
well-circumscribed expansile solitary lytic bone lesion with a narrow zone of transition: wide zone of transition (10 20%) large lesions are more centrally located
soap bubble appearance (47 60%) = expansile remodeling with multiloculated appearance: NO internal mineralization of tumor matrix prominent trabeculation (33 57%): reactive with appositional bone growth
pseudotrabeculation of osseous ridges in endosteal scalloping
no sclerosis (80 85%) / periosteal reaction (10 30%) due to aggressive rapid growth in absence of fracture cortical penetration (33 50%): cortical thinning soft-tissue invasion (25%) complete / incomplete pathologic fracture (11 37%)
destruction of vertebral body with secondary invasion of posterior elements (DDx: ABC, osteoblastoma) frequently vertebral collapse involves adjacent vertebral disks + vertebrae, crosses sacroiliac joint may cross joint space in long bones (exceedingly rare) NUC:
diffusely increased uptake doughnut sign (57%) of central photopenia on delayed bone scintigraphy increased uptake across an articulation + in adjacent joints (62%) due to increased blood flow + disuse osteoporosis and NOT tumor extension
Angio:
hypervascular (60 65%) / hypovascular (20%) / avascular (10%) lesion
CT:
tumor of soft-tissue attenuation similar to muscle with foci of low attenuation (hemorrhage / necrosis): NO matrix mineralization
well-defined margins thin rim of sclerosis (in up to 20%) soft-tissue extension (33 44%) usually at metaphyseal end of tumor aneurysmal bone cyst components (in 14%) of low density with fluid levels joint involvement is unusual except for sacroiliac joint (38%) with sacral lesion significant enhancement
MR:
relatively well-defined lesion of heterogeneous signal intensity with low to intermediate intensity on T1WI + T2WI (63 96%) due to increased cellularity + high collagen content + hemosiderin P.96
HELPFUL feature to distinguish from other subarticular lesions (solitary subchondral cyst, intraosseous ganglion, Brodie abscess, clear cell chondrosarcoma with hyperintense matrix on T2WI)
focal aneurysmal bone cyst components (in 14%) in tumor center with marked hyperintensity on T2WI Direct biopsy to peripheral solid-tissue component to prevent misdiagnosis!
low-signal-intensity margin (= osseous sclerosis / pseudocapsule significant enhancement of solid-tissue component
Cx: | in 5 10% malignant transformation within first 5 years (M:F = 3:1); metastases to lung |
Prognosis: | locally aggressive; 80 90% recurrence rate within first 3 years after initial treatment |
Rx: | currettage + bone grafting (40 60% recurrence); currettage with filling of void with high-speed burr + polymethylmethacrylate (2 25% recurrence); wide resection (7% recurrence) and reconstruction with allografts / metal prosthesis; radiation therapy for inoperable GCT (39 63% recurrence) |
DDx: | (1) Aneurysmal bone cyst (contains only cystic regions; in posterior elements of spine) (2) Brown tumor of HPT (lab values) (3) Osteoblastoma (4) Cartilage tumor: chondroblastoma, enchondroma (not epiphyseal), chondromyxoid fibroma, chondrosarcoma (5) Nonossifying fibroma (6) Bone abscess (7) Hemangioma (8) Fibrous dysplasia (9) Giant cell reparative granuloma |
Multifocal Giant Cell Tumor
= additional GCTs (up to a maximum of 20) developing synchronously / metachronously for up to 20 years without increased risk of pulmonary metastases
Incidence: | <1% of all GCT cases |
Age: | 25 years (range, 11 62 years); M<F |
May be associated with: | Paget disease, usually polyostotic (GCT develops at a mean age of 61 years + after an average time lapse of 12 years) with involvement of skull + facial bones |
Location: | increased prevalence of hands + feet |
Malignant Giant Cell Tumor
= group of giant cell containing lesions capable of malignant behavior + pulmonary metastases
Prevalence: | 5 10% of all GCTs |
Age: | older than patients with benign GCTs |
Types:
Benign metastasizing GCT
Prevalence: 1 5% pulmonary metastases may remain stable / regress spontaneously pulmonary nodules may show peripheral ossification
Prognosis: death in 13% Primary malignant transformation of GCT
= malignant tumor of bone composed of a sarcomatous growth juxtaposed to zones of typical benign GCT without a history of radiation therapy / repeated currettage / resection
Prognosis: median survival time of 4 years
Secondary malignant GCT (86%)
= sarcomatous growth that occurs at a site of previously documented GCT usually after radiation therapy (80%) / repeated resections
Prognosis: median survival time of 1 year
Osteoclastic (giant cell) sarcoma
= highly malignant tumor composed of anaplastic osteoclast-like giant cells without tumor osteoid / bone / cartilage
Glomus Tumor
= hamartoma composed of cells derived from neuro-myoarterial apparatus (regulating blood flow in skin)
Glomus body = encapsulated oval organ of 300 m length; located in reticular dermis (= deepest layer of skin); concentrated in tips of digits (93 501/cm2); composed of an afferent arteriole, an anastomotic vessel (= Sucquet-Hoyer canal lined by endothelium + surrounded by smooth muscle fibers), a primary collecting vein, the intraglomerular reticulum + capsule
Histo: (a) vascular (b) myxoid (c) solid form Prevalence: 1 5% of soft-tissue tumors of hand Age: mostly in 4 5th decade joint tenderness + pain (on average of 4 7 years duration prior to diagnosis)
Love test = eliciting pain by applying precise pressure with a pencil tip
Hildreth sign = disappearance of pain after application of a tourniquet proximally on arm (PATHOGNOMONIC)
@ SUBUNGUAL GLOMUS TUMOR
increased distance between dorsum of phalanx + underside of nail (25%) extrinsic bone erosion (14 25 65%), often with sclerotic border small hypoechoic tumor by US (>3 mm detectable) homogeneously high-signal intensity lesion on T2WI (detectable if >2 mm in diameter)
@ GLOMUS TUMOR OF BONE occasionally within bone
resembles enchondroma
DDx: (1) Mucoid cyst (painless, in proximal nail fold, communicating with DIP joint, associated with osteoarthritis) (2) Angioma (more superficially located)
Gout
= characterized by derangement of purine metabolism manifested by:
hyperuricemia
deposition of positively birefringent monosodium urate monohydrate crystals in synovial fluid leukocytes
gross deposits of sodium urate in periarticular soft tissues (synovial membranes, articular cartilage, ligaments, bursae)
recurrent episodes of arthritis
P.97
Age: | >40 years; males (in women gout may occur after menopause) |
Cause:
Primary Gout (90%)
Incidence: 0.3%; M:F = 20:1; 5% in postmenopausal women Disturbance:
overproduction of uric acid due to inborn error of metabolism
inherited defect in renal urate excretion
Idiopathic (99%)
normal urinary excretion (80 90%)
increased urinary excretion (10 20%)
Specific enzyme / metabolic defect (1%)
increased activity of PP-ribose-P synthetase
partial deficiency of hypoxanthine-guanine phosphoribosyltransferase
Secondary Gout (10%)
Rarely cause for radiographically apparent disease
increased turnover of nucleic acids:
Myeloproliferative disorders + sequelae of their treatment: polycythemia vera, leukemia, lymphoma, multiple myeloma
Blood dyscrasias: chronic hemolysis
increase in purine synthesis de novo due to enzyme defects:
Glycogen storage disease Type I (von Gierke = glucose-6-phosphatase deficiency)
Lesch-Nyhan syndrome (choreoathetosis, spasticity, mental retardation, self-mutilation of lips + fingertips) due to absence of hypo-xanthine-guanine phosphoribosyltransferase
acquired defect in renal excretion of urates (due to reduction in renal function):
Chronic renal failure
Drugs, toxins: lead poisoning
Endocrinologic: myxedema, hypo- / hyperparathyroidism
Vascular: myocardial infarction, hypertension
Histo: | tophus (PATHOGNOMONIC LESION) composed of crystalline / amorphous urates surrounded by highly vascularized inflammatory tissue rich in histiocytes, lymphocytes, fibroblasts, foreign-body giant cells (similar to a foreign-body granuloma) |
Clinical stages in chronologic order:
Asymptomatic hyperuricemia
Acute gouty arthritis
Gout accounts for 5% of all cases of arthritis Precipitated by: trauma, surgery, alcohol, dietary indiscretion, systemic infection monoarticular (90%)
polyarticular (10%): any joint may be affected
Prognosis: usually self-limited (pain resolving within a few hours / days) without treatment
Chronic tophaceous gout
= multiple large urate deposits in intraarticular, extraarticular, intraosseous location
Prevalence: <50% of patients experiencing acute attacks; M:F = 20:1 Histo: cartilage degeneration + destruction, synovial proliferation + pannus, destruction of sub-articular bone + proliferation of marginal bone Distribution: symmetric polyarticular disease (resembling rheumatoid arthritis), asymmetric polyarticular disease, monoarticular disease more severe prolonged attacks
may ulcerate expressing whitish chalky material
Cx: tendon rupture, nerve compression / paralysis
Gouty nephropathy / nephrolithiasis
Acute urate nephropathy
Uric acid urolithiasis
May precede arthritis in up to 20% of cases! renal hypertension
isosthenuria (inability to concentrate urine)
proteinuria
pyelonephritis
Cx: increased incidence of calcium oxalate stones (urate crystals serve as a nidus)
Location:
joints: hands + feet (1st MTP joint most commonly affected = podagra) > ankles > heels > wrists (carpometacarpal compartment especially common and severe) > fingers > elbows; knees; shoulder; sacroiliac joint (15%, unilateral);
involvement of hip + spine is rare
bones, tendon, bursa, bones
external ear; pressure points over elbow, forearms, knees, feet
Radiologic features usually not seen until 6 12 years after initial attack Radiologic features present in 45% of inflicted patients @ Soft tissues
eccentric juxtaarticular lobulated soft-tissue masses (hand, foot, ankle, elbow, knee) Site: tendency for extensor tendons, eg, quadriceps, triceps, Achilles tendon calcific deposits in periphery of gouty tophi in 50% (sodium urate crystals are not radiopaque, tophi radiographically visible only after calcium deposition of an underlying abnormality of calcium metabolism) bilateral effusion of bursae olecrani (PATHOGNOMONIC), prepatellar bursa aural calcification
@ Joints
joint effusion (earliest sign) periarticular swelling (in acute monoarticular gout) preservation of joint space until late in disease (IMPORTANT CLUE): cartilage destruction (late in course of disease)
absence of periarticular demineralization (due to short duration of attacks; important DDx for rheumatoid arthritis) eccentric erosions with thin sclerotic margins: scalloped erosion of bases of ulnar metacarpals
chondrocalcinosis (5%): Location: menisci (fibrocartilage only) Patients with gout have a predisposition for calcium pyrophosphate dihydrate deposition disease (CPPD) P.98
Cx: secondary osteoarthritis
round / oval well-marginated subarticular cysts (pseudotumor) up to 3 cm (containing tophus / urate crystal-rich fluid) DDx: rheumatoid arthritis (marginal erosions without sclerotic rim, periarticular demineralization)
@ Bone
punched-out lytic bone lesion sclerosis of margin = mouse / rat bite from erosion of long-standing soft-tissue tophus overhanging margin (40%) = elevated osseous spicule separating tophaceous nodule from adjacent erosion (in intra- and extraarticular locations) (HALLMARK) proliferative bone changes: club-shaped metatarsals, metacarpals, phalanges enlargement of ulnar styloid process diaphyseal thickening
ischemic necrosis of femoral / humeral heads intraosseous calcification: punctate / circular calcifications of subchondral / subligamentous regions (DDx: enchondroma) bone infarction due to deposits at vascular basement membrane (DDx: bone island)
@ Kidney
renal stones (in up to 20%): pure uric acid stones (84%): radiolucent on radiographs, hyperdense on CT
uric acid + calcium oxalate (4%)
pure calcium oxalate / calcium phosphate (12%)
MR:
tophus (most frequently) isointense to muscle on T1WI low or intermediate signal intensity on T2WI homogeneous intense enhancement
Rx: | colchicine, allopurinol (effective treatment usually does not improve roentgenograms) |
DDx:
CPPD (pseudogout symptomatology, polyarticular chondrocalcinosis involving hyaline and fibrocartilage + degenerative arthropathy with joint space narrowing)
Psoriasis (progressive joint space destruction, paravertebral ossification, sacroiliac joint involvement)
Rheumatoid arthritis (nonproliferative marginal bone erosions, fusiform soft-tissue swelling, symmetric distribution, early joint-space narrowing, osteopenia)
Joint infection (rapid destruction of joint space, loss of articular cortex over a continuous segment)
Amyloidosis (bilateral symmetric involvement, periarticular osteopenia)
Xanthomatosis (laboratory work-up)
Osteoarthritis (symmetric distribution, elderly women)
Granulocytic Sarcoma
= CHLOROMA = MYELOBLASTOMA
= extramedullary solid tumor consisting of primitive precursors of the granulocytic series of WBCs (myeloblasts, promyelocytes, myelocytes)
Clinical setting:
patient with acute myelogenous leukemia (in 3 8%)
harbinger of AML in nonleukemic patient (usually developing within 1 year)
indicator of impending blast crisis in CML (in 1%) / leukemic transformation in myelodysplastic syndromes (polycythemia rubra vera, myelofibrosis with myeloid metaplasia, hypereosinophilic syndrome)
isolated event
60% are of green color (chloroma) due to high levels of myeloperoxidase (30% are white / gray / brown depending on preponderance of cell type + oxidative state of myeloperoxidase)
Location: orbit, soft tissue, skin, paranasal sinus, lymph node, periosteum, organs, bowel; often multiple Site: propensity for bone marrow (arises from bone marrow traversing haversian canal + reaching the periosteum), perineural + epidural tissue osteolysis with ill-defined margins homogeneous enhancement on CT / MR (DDx to hematoma / abscess) MR:
isointense to brain / bone marrow / muscle on T1WI + T2WI Prognosis: resolution under chemotherapy radiation therapy; recurrence rate of 23% DDx: osteomyelitis, histiocytosis X, neuroblastoma, lymphoma, multiple myeloma
Gunshot Injury
Firearms: | handgun, rifle (great energy), shotgun |
Projectiles:
bullet:
jacketed bullet with mantle of copper
semijacketed bullet = exposed lead at tip
nonjacketed bullet
pellets of steel / lead:
birdshot = small pellets
buckshot =large pellets
Assessment:
Type of projectile
fully jacketed bullets show no trail of lead fragments semi- / nonjacketed bullets distribute lead fragments along bullet track hollow-point bullets transform into mushroom shape lead snowstorm of high-velocity soft-point rifle bullets: conical distribution with apex pointing toward entry site
steel pellets remain round, lead pellets become deformed + fragmented No Caption Available.
Path of projectile
bullet tips points to entry wound (after tumbling through 180 ): impact deformation of bullet modifies tumbling
bullet + bone fragments deposited along track bone fracture beveled toward the direction of travel
Extent of injury
P.99
Cx: | pellet embolization, magnetization in MRI |
Hemangioendothelial sarcoma
= HEMANGIOENDOTHELIOMA = HEMANGIOEPITHELIOMA
= neoplasm of vascular endothelial cells of intermediate aggressiveness with either benign or malignant behavior
Histo: irregular anastomosing vascular channels lined by one / several layers of atypical anaplastic endothelial cells Age: 4th 5th decade; M:F = 2:1 history of trauma / irradiation
Soft-tissue Hemangioendothelioma (common)
Location: | deep tissues of extremities |
Site: | in 50% closely related to a vessel (often a vein) |
Osseous Hemangioendothelioma (rare)
Age: | 2nd 3rd decade of life; M > F |
Location: | calvarium, spine, femur, tibia, humerus, pelvis; multicentric lesions in 30% often with regional distribution (less aggressive) |
eccentric lesion in metaphysis of long bones osteolytic aggressively destructive area with indistinct margins (high grade) well-demarcated margins with scattered bony trabeculae (low grade) osteoblastic area in vertebrae, contiguous through several vertebrae
Metastases to: | lung (early) |
Prognosis: | 26% 5-year survival rate |
DDx: | aneurysmal bone cyst, poorly differentiated fibrosarcoma, highly vascular metastasis, alveolar rhabdomyosarcoma |
Hemangioma
Most common benign soft-tissue tumor of vascular origin!
Histo: | frequently containing variable amounts of nonvascular elements: fat, smooth muscle, fibrous tissue, bone, hemosiderin, thrombus Fat overgrowth may be so extensive that some lesion may be misdiagnosed as a lipoma! |
CAPILLARY HEMANGIOMA (most common)
= small-caliber vessels lined by flattened epithelium
Site: skin, subcutaneous tissue; vertebral body Age: first few years of life Juvenile capillary hemangioma = strawberry nevus
Prevalence: 1:200 births; in 20% multiple Prognosis: involutes in 75 90% by age 7 years Verrucous capillary hemangioma
Senile capillary hemangioma
enlarged arteries + arteriovenous shunting pooling of contrast material
CAVERNOUS HEMANGIOMA
= dilated blood-filled spaces lined by flattened endothelium
Site: deeper soft tissues, frequently intramuscular; calvarium Age: childhood phleboliths = dystrophic calcification in organizing thrombus (in nearly 50%) large cystic spaces enlarged arteries + arteriovenous shunting pooling of contrast material Prognosis: NO involution
ARTERIOVENOUS HEMANGIOMA
= persistence of fetal capillary bed with abnormal communications of an increased number of normal / abnormal arteries and veins
Etiology: (?) congenital arteriovenous malformation Age: young patients Site: soft tissues superficial lesion without arteriovenous shunting
deep lesion with arteriovenous shunting
limb enlargement, bruit
distended veins, overlying skin warmth
Branham sign = reflex bradycardia after compression
large tortuous serpentine feeding vessels fast blood flow + dense staining early draining veins
VENOUS HEMANGIOMA
= thick-walled vessels containing muscle
Site: deep soft tissues of retroperitoneum, mesentery, muscles of lower extremities Age: adulthood phleboliths serpentine vessels with slow blood flow vessels oriented along long axis of extremity (in 78%) + neurovascular bundle (in 64%) multifocal involvement (in 37%) muscle atrophy with increased subcutaneous fat may be normal on arterial angiography
Osseous Hemangioma
Incidence: | 10% |
Histo: | mostly cavernous; capillary type is rare |
Age: | 4th 5th decade; M:F = 2:1 |
usually asymptomatic
@ Vertebra (28% of all skeletal hemangiomas)
Incidence: in 5 11% of all autopsies; multiple in 1/3 Histo: capillary hemangioma interspersed in fatty matrix The larger the degree of fat overgrowth, the less likely the lesion will be symptomatic! Age: >40 years; female Location: in lower thoracic / upper lumbar spine accordion / corduroy / honeycomb vertebra = coarse vertical trabeculae with osseous reinforcement adjacent to bone resorption caused by vascular channels (also in multiple myeloma, lymphoma, metastasis) bulge of posterior cortex extraosseous extension beyond bony lesion into spinal canal (with cord compression) / neural foramina paravertebral soft-tissue extension lesion enhancement (due to hypervascularity) CT:
polka-dot appearance = small punctate areas of sclerosis (= thickened vertical trabeculae)
MR:
mottled pattern of low-to-high intensity on T1WI + very-high intensity on T2WI depending on degree of adipose tissue (CHARACTERISTIC)
Cx: vertebral collapse (unusual), spinal cord compression
P.100
@ Calvarium (20% of all hemangiomas)
Location: frontal / parietal region Site: diploe <4 cm round osteolytic lesion with sunburst / weblike / spoke-wheel appearance of trabecular thickening expansion of outer table to a greater extent than inner table producing palpable lump
@ Flat bones & long bones (rare)
ribs, clavicle, mandible, zygoma, nasal bones, metaphyseal ends of long bones (tibia, femur, humerus)
radiating trabecular thickening bubbly bone lysis creating honeycomb / latticelike / hole-within-hole appearance MR:
serpentine vascular channels with low signal intensity on T1WI + high signal intensity on T2WI (= slow blood flow) / low signal intensity on all sequences (= high blood flow)
NUC (bone / RBC-labeled scintigraphy):
photopenia / moderate increased activity
Soft-tissue Hemangioma
Incidence: | 7% of all benign tumors; most frequent tumor of infancy + childhood |
Age: | primarily in children; M < F |
May be associated with: | Maffucci syndrome (= multiple cavernous hemangiomas + enchondromas) |
intermittent change in size
painful
bluish discoloration of overlying skin (rare)
may dramatically increase in size during pregnancy
Location: usually intramuscular; synovia (<1% of all hemangiomas); common in head and neck nonspecific soft-tissue mass may extend into bone creating subtle rounded / linear areas of hyperlucency (rare) longitudinal / axial bone overgrowth (secondary to chronic hyperemia) may contain phleboliths (30% of lesions, SPECIFIC) nonspecific curvilinear / amorphous calcifications may contain such large amounts of fat as to be indistinguishable from lipoma CT:
poorly defined mass with attenuation similar to muscle areas of decreased attenuation approximating subcutaneous fat (= fat overgrowth) most prominent in periphery of lesion
MR:
poorly marginated mass hypo- / isointense to muscle on T1WI areas with increased signal intensity on T1WI in periphery of lesion extending into septations (= fat) well-marginated markedly hyperintense mass on T2WI (increased free water content in stagnant blood) with striated / septated configuration tubular structures with blood flow characteristics (flow void / inflow enhancement; marked contrast enhancement) phleboliths as low-intensity areas inside lesion high-signal-intensity areas on T1WI + T2WI (= hemorrhage)
US:
complex mass low-resistance arterial signal (occasionally)
Synovial Hemangioma
repetitive bleeding into joint
Location: knee (60%), elbow (30%) DDx: hemophilic arthropathy (polyarticular)
Hemangiopericytoma
= borderline tumor with benign / locally aggressive / malignant behavior (counterpart of glomus tumor)
Age: 4th 5th decade; M:F = 1:1 Path: large vessels predominantly in tumor periphery Histo: cells packed around vascular channels containing cystic + necrotic areas; arising from cells of Zimmerman that are located around vessels @ Soft tissue
= deep-seated well-circumscribed lesion arising in muscle
Location: lower extremity in 35% (thigh), pelvic cavity, retroperitoneum painless slowly growing mass up to 20 cm
@ Bone (rare)
Location: lower extremity, vertebrae, pelvis, skull (dura similar to meningioma) osteolytic lesions in metaphysis of long / flat bone subperiosteal large blowout lesion (similar to aneurysmal bone cyst)
Angio:
displacement of main artery pedicle of tumor feeder arteries spider-shaped arrangement of vessels encircling tumor small corkscrew arteries dense tumor stain
DDx: hemangioendothelioma, angiosarcoma
Hemochromatosis
= excess iron deposition in tissues (hemosiderosis) resulting in tissue injury
Primary / Idiopathic Hemochromatosis
= autosomal recessive genetic disorder (abnormal iron-loading gene on short arm of chromosome 6) in thalassemia, sideroblastic anemia
Defect: increased absorption + parenchymal accumulation of dietary iron Organs: liver, pancreas, heart (parenchymal iron overload) Homozygous frequency: 1:200; M:F = 1:1 Age: >30 years (M), usually after menopause (F); females protected by menstruation cirrhosis (frequently present at time of diagnosis)
bronzed diabetes (50%) = insulin-dependent diabetes (excess intracellular iron reduces function of beta islet cells while reserve capacity of exocrine function is not exceeded by toxic effects of iron)
congestive cardiomyopathy (myocardial muscle accumulates toxic levels of intracellular iron)
skin pigmentation
hypogonadism + decreased libido (2 to pituitary dysfuncton)
slowly progressive arthritic symptoms (30%)
increased serum iron + ferritin level (nonspecific)
transferrin saturation + serum ferritin assay (specific)
@ Skeleton
Distribution: most commonly in hands (metacarpal heads, particularly 2nd + 3rd MCP joints), carpal (30 50%) + proximal interphalangeal joints, knees, hips, elbows generalized osteoporosis small subchondral cystlike rarefactions with fine rim of sclerosis (metacarpal heads) arthropathy in 50% (iron deposition in synovium) uniform symmetric joint space narrowing (unusual for degenerative joint disease) enlargement of metacarpal heads: hook-like osteophytes on radial aspect of metacarpal heads (CHARACTERISTIC)
chondrocalcinosis in >60%, knees most commonly affected calcium pyrophosphate deposition (inhibition of pyrophosphatase enzyme within cartilage which hydrolyzes pyrophosphate to soluble orthophosphate)
calcification of triangular cartilage of wrist, menisci, annulus fibrosus, ligamentum flavum, symphysis pubis, Achilles tendon, plantar fascia
@ Brain
marked loss in signal intensity of anterior lobe of pituitary gland (iron deposition)
@ Abdomen
decreased T2 signal intensity in liver, pancreas normal T2 signal intensity of spleen on T2WI + T2*WI
P.101
Dx: | liver biopsy with hepatic iron index > 2 (= iron concentration in mol/g of dry weight divided by patient's age in years) |
Cx: | hepatoma in 14% (iron stimulates growth of neoplasms) |
Prognosis: | death from CHF (30%), death from hepatic failure (25%), death from HCC (in up to 33%) |
Rx: | (1) Phlebotomy (return of life expectancy to normal if instituted prior to complications) (2) Screening of family members (gene can be located by human leukocyte antigen typing) |
DDx: | Pseudogout (no arthropathy) (2) Psoriatic arthritis (skin + nail changes) (3) Osteoarthritis (predominantly distal joints in hands) (4) Rheumatoid arthritis (5) Gout (may also have chondrocalcinosis) |
Secondary Hemochromatosis
= nongenetic iron overload
ineffective erythropoiesis: thalassemia major increased demand for iron resulting in increased absorption + retention of dietary iron
Cx: increase in parenchymal iron Bantu siderosis = parenchymal + RES iron overload due to extensive use of iron pots for cooking
Transfusional Siderosis
= iron overload of the RES (NOT a form of secondary hemochromatosis); iron less toxic [siderosis = exposure to excess iron]
Pathophysiology: large number of damaged erythrocytes from blood transfusions are incorporated into RES cells + undergo lysis with liberation of iron from hemoglobin (extravascular hemolysis) Organs of RES: Kupffer cells, spleen, bone marrow decreased signal intensity of liver + spleen on T2WI Iron storage capacity of RES: 10 g (equivalent to 40 units of packed RBCs)
Hemolytic Anemia
Cause:
Anemia:
Sickle cell disease
Thalassemia
Hereditary spherocytosis
Paroxysmal nocturnal hemoglobulinuria
Chronic / severe blood loss
Marrow replacement by neoplastic cells
Treatment with granulocyte-macrophage colony-stimulating factor
Reconversion = recruitment of yellow marrow for hematopoiesis once hematopoietic capacity of existing red marrow stores is exceeded
Order of reconversion: | spine > flat bones > skull > long bones (proximal > distal metaphysis > diaphysis > epi- / apophyses) |
MR:
signal intensity of hyperplastic marrow similar to muscle on T1WI + T2WI + STIR red marrow hypointense relative to fat on T2WI low signal intensity of renal cortex on T1WI + T2WI due to hemosiderin deposition (after intravascular hemolysis)
Cx:
Hemosiderosis (histologic term of iron deposition in tissue) = excess iron in cells of RES 2 to repeated blood transfusions
magnetic susceptibility effects of hemosiderin produce hypointense marrow on T2WI (+ T1WI if hemosiderosis severe)
Medullary infarction (common in sickle cell disease)
DDx: | leukemia (hyperintense on STIR) |
Hemophilia
= X-linked deficiency / functional abnormality of coagulation factor VIII (= hemophilia A) in >80% / factor IX (= hemophilia B = Christmas disease)
Incidence: | 1:10,000 males |
Hemophilic Arthritis |
P.102
Hemophilic Arthropathy (most common)
Cause: | repeated bleeding into synovial joint |
Path: | pannus formation erodes cartilage with loss of subchondral bone plate and formation of subarticular cysts |
Histo: | synovial hyperplasia, chronic inflammatory changes, fibrosis, siderosis of synovial membrane |
Age: | 1st and 2nd decade |
tense red warm joint with decreased range of motion (muscle spasm)
fever, elevated WBC (DDx: septic arthritis)
Location: knee > ankle > elbow > shoulder; commonly bilateral although bleeding episodes tend to recur within same joint joint effusion (= hemarthrosis) enlargement of epiphysis (secondary to synovial inflammation + hyperemia) juxtaarticular osteoporosis (secondary to synovial inflammation + hyperemia) joint space narrowing (particularly patella) secondary to cartilaginous denudation erosion of articular surface with multiple subchondral cysts sclerosis + osteophytosis (secondary to superimposed degenerative joint disease) @ Knee
squared patella widening of intercondylar notch flattening of condylar surface medial slanting of tibiotalar joint
MR:
low signal intensity of hypertrophied synovial membrane on all pulse sequences (due to magnetic susceptibility effect of hemosiderin) varying intensity of subarticular defects (depending on substrate: fluid / soft tissue / hemosiderin)
Hemophilic Pseudotumor (1 2%)
= posthemorrhagic cystic swelling within muscle + bone characterized by pressure necrosis + destruction
(a) juvenile form = usually multiple intramedullary expansile lesions without soft-tissue mass in small bones of hand / feet (before epiphyseal closure)
(b) adult form = usually single intramedullary expansile lesion with large soft-tissue mass in ilium / femur
(c) soft-tissue involvement of retroperitoneum (psoas muscle), bowel wall, renal collecting system
mixed cystic expansile lesion bone erosion + pathologic fracture CT:
sometimes encapsulated mass containing areas of low attenuation + calcifications
MR:
hemorrhage of varying age
Cx: | joint contracture (after repeated bleeding into muscle) |
N.B.: | Needle aspiration / biopsy / excision may cause fistulae / infection / uncontrolled bleeding! |
Rx: | palliative radiation therapy (destroys vessels prone to bleed) + transfusion of procoagulation factor concentrate |
Hereditary hyperphosphatasia
= JUVENILE PAGET DISEASE
= rare autosomal recessive disease with sustained elevation of serum alkaline phosphatase, especially in individuals of Puerto Rican descent
Histo: rapid turnover of lamellar bone without formation of cortical bone; immature woven bone is rapidly laid down, but simultaneous rapid destruction prevents normal maturation Age: 1st 3rd year; usually stillborn rapid enlargement of calvarium + long bones
dwarfism
cranial nerve deficit (blind, deaf)
hypertension
frequent respiratory infections
pseudoxanthoma elasticum
elevated alkaline phosphatase
deossification = decreased density of long bones with coarse trabecular pattern metaphyseal growth deficiency wide irregular epiphyseal lines (resembling rickets in childhood), persistent metaphyseal defects (40% of adults) bowing of long bones + fractures with irregular callus widened medullary canal with cortical thinning (cortex modeled from trabecular bone) skull greatly thickened with wide tables, cotton wool appearance vertebra plana OB-US:
diagnosis suspected in utero in 20%
Cx: pathologic fractures; vertebra plana universalis DDx: (1) Osteogenesis imperfecta (2) Polyostotic fibrous dysplasia
(3) Paget disease (> age 20, not generalized)
(4) Pyle disease (spares midshaft)
(5) van Buchem syndrome (only diaphyses > age 20, no long-bone bowing)
(6) Engelmann syndrome (lower limbs)
Hereditary Multiple Diaphyseal Sclerosis
= RIBBING DISEASE
Herniation Pit on AP and LAT Radiographs
= autosomal recessive disorder similar to Engelmann-Camurati disease
Age: after puberty mild neuromuscular symptoms
Location: long bones only unilateral asymmetric / asynchronous bilateral sclerosis DDx: Engelmann-Camurati disease (begins in childhood, severe neuromuscular symptoms, symmetric bilateral sclerosis of long bones, skull involved)
P.103
Hereditary Spherocytosis
= autosomal dominant congenital hemolytic anemia
Age: anemia begins in early infancy to late adulthood rarely severe anemia
jaundice
spherocytes in peripheral smear
bone changes rare (due to mild anemia); long bones rarely affected widening of diploe with displacement + thinning of outer table hair-on-end appearance Rx: splenectomy corrects anemia even though spherocytemia persists improvement in skeletal alterations following splenectomy
Herniation Pit
= SYNOVIAL HERNIATION PIT = CONVERSION DEFECT
= ingrowth of fibrous + cartilaginous elements from adjacent joint through perforation in cortex
Histo: fibroalveolar tissue Age: usually in older individuals may be symptomatic
no clinical significance
Location: anterior superolateral aspect of proximal femoral neck; uni- or bilateral Site: subcortical well-circumscribed round lucency usually <1 cm in diameter; may enlarge over time reactive thin sclerotic border hyperintense area on T2WI (= fluid signal intensity) bone scan may be positive
Holt-Oram Syndrome
Autosomal dominant; M < F
Associated with CHD: | secundum type ASD (most common), VSD, persistent left SVC, tetralogy, coarctation |
intermittent cardiac arrhythmia
bradycardia (50 60/min)
Location: upper extremity only involved; symmetry of lesions is the rule; left side may be more severely affected aplasia / hypoplasia of radial structures: thumb, 1st metacarpal, carpal bones, radius fingerized hypoplastic thumb / triphalangeal thumb slender elongated hypoplastic carpals + metacarpals hypoplastic radius; absent radial styloid shallow glenoid fossa (voluntary dislocation of shoulder common) hypoplastic clavicula high arched palate cervical scoliosis pectus excavatum
Homocystinuria
Autosomal recessive disorder
Etiology: | cystathionine B synthetase deficiency results in defective methionine metabolism with accumulation of homocystine + homocysteine in blood and urine; causes defect in collagen / elastin structure |
thromboembolic phenomena due to stickiness of platelets
ligamentous laxity
downward + inward dislocation of lens (DDx: upward + outward dislocation in Marfan syndrome)
mild / moderate mental retardation
crowding of maxillary teeth and protrusion of incisors
malar flush
arachnodactyly in 1/3 (DDx: Marfan syndrome) microcephaly enlarged paranasal sinuses osteoporosis of vertebrae (biconcave / flattened / widened vertebrae) scoliosis pectus excavatum / carinatum (75%) osteoporosis of long bones (75%) with bowing + fracture children: metaphyseal cupping (50%); enlargement of ossification centers in 50% (knee, carpal bones); epiphyseal calcifications (esp. in wrist, resembling phenylketonuria); delayed ossification Harris lines = multiple growth lines genu valgum, coxa valga, coxa magna, pes cavus Differences between Homocystinuria and Marfan
Homocystinuria Marfan Syndrome Inheritance autosomal recessive autosomal dominant Biochemical defect cystathionine synthetase not known Osteoporosis yes no Spine biconcave vertebrae scoliosis Lens dislocation downward upward Arachnodactyly 33% 100% premature vascular calcifications Prognosis: death from occlusive vascular disease / minor vascular trauma
P.104
Hyperparathyroidism
= uncontrolled production of parathyroid hormone
Age: 3rd 5th decade; M:F = 1:3 Histo: decreased bone mass secondary to increased number of osteoclasts, increased osteoid volume (defect in mineralization), slightly increased number of osteoblasts increase in parathyroid hormone (100%)
increase in serum alkaline phosphatase (50%)
elevation of serum calcium (due to accelerated bone turnover and increased calcium absorption) + decrease in serum phosphate (30%)
hypotonicity of muscles, weakness, constipation, difficulty in swallowing, duodenal / gastric peptic ulcer disease (secondary to hypercalcemia)
polyuria, polydipsia (hypercalciuria + hyperphosphaturia)
renal colic + renal insufficiency (nephrocalculosis + nephrocalcinosis)
rheumatic bone pain + tenderness (particularly at site of brown tumor), pathologic fracture secondary to brown tumor
BONE RESORPTION
subperiosteal (most constant + specific finding; virtually PATHOGNOMONIC of hyperparathyroidism):
lacelike irregularity of cortical margin; may progress to scalloping / spiculation (pseudoperiostitis) Site: phalangeal tufts (earliest involvement), radial aspect of middle phalanx of 2nd + 3rd finger beginning in proximal metaphyseal region (early involvement), bandlike zone of resorption in middle / base of terminal tuft, distal end of clavicles, medial tibia plateau, medial humerus neck, medial femoral neck, distal ulna, superior + inferior margins of ribs in midclavicular line, lamina dura of skull and teeth
subchondral:
pseudowidening of joint space collapse of cortical bone + overlying cartilage with development of erosion, cyst, joint narrowing (similar to rheumatoid arthritis) Site: DIP joint (most commonly 4th + 5th digit), MCP joint, PIP joint, distal clavicle, acromioclavicular joint (clavicular side), pseudowidening of sacroiliac joint (iliac side), sternoclavicular joint, symphysis pubis, scalloping of posterior surface of patella, Schmorl nodes; typically polyarticular
cortical (due to osteoclastic activity within haversian canal):
intracortical tunneling scalloping along inner cortical surface (endosteal resorption)
trabecular:
spotty deossification with indistinct + coarse trabecular pattern granular salt and pepper skull loss of distinction between inner and outer table ground-glass appearance
subligamentous:
bone resorption with smooth scalloped / irregular ill-defined margins Site: inferior surface of calcaneus (long plantar tendons + aponeurosis), inferior aspect of distal clavicle (coracoclavicular ligament), greater trochanter (hip abductors), lesser trochanter (iliopsoas), anterior inferior iliac spine (rectus femoris), humeral tuberosity (rotator cuff), ischial tuberosity (hamstrings), proximal extensor surface of ulna (anconeus), posterior olecranon (triceps)
BONE SOFTENING
basilar impression of skull wedged vertebrae, kyphoscoliosis, biconcave vertebral deformities bowing of long bones slipped capital femoral epiphysis
BROWN TUMOR
= OSTEOCLASTOMA
Cause: PTH-stimulated osteoclastic activity (more frequent in 1 HPT; in 1.5% of 2 HPT) Path: localized replacement of bone by vascularized fibrous tissue (osteitis fibrosa cystica) containing giant cells; lesions may become cystic following necrosis + liquefaction Location: jaw, pelvis, rib, metaphyses of long bones (femur), facial bones, axial skeleton Site: often eccentric / cortical; frequently solitary expansile lytic well-marginated cystlike lesion (DDx: giant cell tumor) without adjacent reactive bone formation endosteal scalloping destruction of midportions of distal phalanges with telescoping
OSTEOSCLEROSIS
More frequent in 2 HPT
Cause: ? PTH-stimulated osteoblastic activity,? role of calcitonin (poorly understood) Site: strong predilection for axial skeleton, pelvis, ribs, clavicles, metaphysis + epiphysis of appendicular skeleton rugger jersey spine
SOFT-TISSUE CALCIFICATION
More frequent in 2 HPT; metastatic calcification when Ca P product >70 mg/dL
cornea, viscera (lung, stomach, kidney)
periarticular in hip, knee, shoulder, wrist
arterial tunica media (resembling diabetes mellitus)
chondrocalcinosis (15 18%) = calcification of hyaline / fibrous cartilage in menisci, wrist, shoulder, hip, elbow
EROSIVE ARTHROPATHY
asymptomatic
simulates rheumatoid arthritis with preserved joint spaces
PERIOSTEAL NEW-BONE FORMATION
Cause: PTH-stimulation of osteoblasts Site: pubic ramus along iliopectineal line (most frequent), humerus, femur, tibia, radius, ulna, metacarpals, metatarsals, phalanges linear new bone paralleling cortical surface; may be laminated; often separated from cortex by radiolucent zone increase in cortical thickness (if periosteal reaction becomes incorporated into adjacent bone)
P.105
Sequelae:
Renal stones / nephrocalcinosis (70%)
Increased osteoblastic activity (25%)
increased alkaline phosphatase osteitis fibrosa cystica
subperiosteal bone resorption + cortical tunneling brown tumors (primary HPT)
bone softening
fractures
Peptic ulcer disease (increased gastric secretion from gastrinoma)
Calcific pancreatitis
Soft-tissue calcifications (2 HPT)
Marginal joint erosions + subarticular collapse (DIP, PIP, MCP)
Primary Hyperparathyroidism
= pHPT = 1 HPT = hypercalcemia due to uncontrolled secretion of parathormone by one / more hyperfunctioning parathyroid glands featuring
brown tumor
chondrocalcinosis (20 30%)
requires surgical Rx
Incidence: | 25:100,000 per year; incidence of bone lesions in HPT is 25 40% |
Etiology:
Parathyroid adenoma (87%): single (80%); multiple (7%)
Parathyroid hyperplasia (10%): chief cell (5%); clear cell (5%)
Parathyroid carcinoma (3%)
Histo: | increased number of osteoclasts, increased osteoid volume (defect in mineralization), slightly increased osteoblasts = decreased bone mass |
Age: | 3rd 5th decade; M:F = 1:3 |
Associated with:
Wermer syndrome = MEA I (+ pituitary adenoma + pancreatic islet cell tumor)
Sipple syndrome = MEA II (+ medullary thyroid carcinoma + pheochromocytoma)
X-RAY (skeletal involvement in 10 20%):
thin cortices with lacy cortical pattern (subperiosteal bone resorption) Differences between 1 and 2 HPT
Skeletal Findings 1 HPT 2 HPT Osteopenia, diffuse present present Osteosclerosis, regional / diffuse rare common Bone resorption common common Brown tumor common less common Soft-tissue calcification not infrequent common Chondrocalcinosis not infrequent rare brown tumor (particularly in jaw + long bones) osteitis cystica fibrosa (= intertrabecular fibrous connective tissue)
NUC:
normal bone scan in 80% foci of abnormal uptake: calvarium (especially periphery), mandible, sternum, acromioclavicular joint, lateral humeral epicondyles, hands increased uptake in brown tumors extraskeletal uptake: cornea, cartilage, joint capsules, tendons, periarticular areas, lungs, stomach normal renal excretion [except in stone disease / calcium nephropathy (10%)]
Rx: | pathologic glands identified by experienced surgeons in 90 95% on initial neck exploration (ectopic + supernumerary glands often overlooked at operation; recurrent hypercalcemia in 3 10%) |
Surgical risk for repeat surgery:
6.6% | recurrent laryngeal nerve injury |
20.0% | permanent hypoparathyroidism |
<1.0% | perioperative mortality |
Secondary Hyperparathyroidism
= sHPT = 2 HPT = diffuse / adenomatous hyperplasia of all four parathyroid glands as a compensatory mechanism in any state of hypocalcemia featuring (1) soft-tissue calcifications (2) osteosclerosis
requires medical Rx Etiology:
renal osteodystrophy (renal insufficiency + osteomalacia / rickets)
calcium deprivation, maternal hypoparathyroidism, pregnancy, hypovitaminosis D
rise in serum phosphate leading to decrease in calcium by feedback mechanism
low to normal calcium levels
Ca2+ PO42- solubility product often exceeded
NUC:
superscan in 2 HPT: absent kidney sign increased bone-to-soft tissue uptake ratio increased uptake in calvarium, mandible, acromioclavicular region, sternum, vertebrae, distal third of long bones, ribs
diffuse Tc-99m MDP uptake in lungs (60%)
Tertiary Hyperparathyroidism
= tHPT = 3 HPT = development of autonomous PTH adenoma in patients with chronically overstimulated hyperplastic parathyroid glands (renal insufficiency + prolonged renal dialysis)
requires surgical Rx Clue: (a) intractable hypercalcemia (b) inability to control osteomalacia by vitamin D administration
Ectopic Parathormone Production
= pseudohyperparathyroidism as paraneoplastic syndrome in bronchogenic carcinoma + renal cell carcinoma
P.106
Hypertrophic Osteoarthropathy
= HYPERTROPHIC PULMONARY OSTEOARTHROPATHY (HPO) = Marie-Bamberger disease
= paraneoplastic syndrome
Etiology: | (1) Release of vasodilators which are not metabolized by lung (2) Increased flow through AV shunts (3) Reflex peripheral vasodilation (vagal impulses) (4) Hormones: estrogen, growth hormone, prostaglandin |
Histo: | round cell infiltration of the outer fibrous layer of periosteum followed by new bone proliferation |
THORACIC CAUSES
malignant tumor (0.7 12%): bronchogenic carcinoma (88%), mesothelioma, lymphoma, pulmonary metastasis from osteogenic sarcoma, melanoma, renal cell carcinoma, breast cancer
4 17% of patients with bronchogenic carcinoma ma develop HPO!
benign tumor: benign pleural fibroma, tumor of ribs, thymoma, esophageal leiomyoma, pulmonary hemangioma, pulmonary congenital cyst
chronic infection / inflammation: pulmonary abscess, bronchiectasis, blastomycosis, TB (very rare); cystic fibrosis, interstitial fibrosis
cyanotic congenital heart disease with R-to-L shunt
EXTRATHORACIC CAUSES (less common)
GI tract: ulcerative colitis, amebic + bacillary dysentery, intestinal TB, Whipple disease, Crohn disease, gastric ulcer, bowel lymphoma, gastric carcinoma
liver disease: biliary + alcoholic cirrhosis, posthepatic cirrhosis, chronic active hepatitis, bile duct carcinoma, benign bile duct stricture, amyloidosis, liver abscess
undifferentiated nasopharyngeal carcinoma, pancreatic carcinoma, chronic myelogenous leukemia
burning pain, painful swelling of limbs, and stiffness of joints: ankles (88%), wrists (83%), knees (75%), elbows (17%), shoulders (10%), fingers (7%)
peripheral neurovascular disorders: local cyanosis, areas of increased sweating, paresthesia, chronic erythema, flushing + blanching of skin
hippocratic fingers + toes (clubbing)
hypertrophy of extremities (soft-tissue swelling)
Location: | tibia + fibula (75%), radius + ulna (80%), proximal phalanges (60%), femur (50%), metacarpus + metatarsus (40%), humerus + distal phalanges (25%), pelvis (5%); unilateral (rare) Spine, pelvis, ribs usually spared! |
Site: | in diametaphyseal regions |
cortical thickening lamellar periosteal proliferation of new bone, at first smooth then undulating + rough Site: most conspicuous on concavity of long bones (dorsal + medial aspects) soft-tissue swelling ( clubbing ) of distal phalanges Bone scan (reveals changes early with greater sensitivity + clarity):
parallel track / double stripe / tramline sign = patchy linear diffusely increased symmetric uptake along cortical margins of metaphysis + diaphysis of tubular bones (= periostitis) increased periarticular uptake (= synovitis) scapular involvement in 2/3 mandible maxilla abnormal in 40%
Prognosis: | treatment of underlying condition leads to remission of symptoms often within 24 hours + regression of radiographic findings in months |
DDx: | (1) Pachydermoperiostosis (self-limited, adolescence, autosomal dominant, M>F) (2) Metastases (axial skeleton, focal asymmetric distribution) (3) Chronic vascular insufficiency (4) Thyroid acropachy (5) Hypervitaminosis A |
Hypervitaminosis A
Age: | usually infants + children |
Cause: | overdosing vitamin A, 13-cis-retinoic acid (treatment for neuroblastoma) |
anorexia, irritability loss of hair, dry skin, pruritus, fissures of lips
jaundice, enlargement of liver
separation of cranial sutures secondary to hydrocephalus (coronal > lambdoid) in children <10 years of age, may appear within a few days symmetrical solid periosteal new-bone formation along shafts of long + short bones (ulna, clavicle) premature epiphyseal closure + thinning of epiphyseal plates accelerated growth tendinous, ligamentous, pericapsular calcifications changes usually disappear after cessation of vitamin A ingestion DDx: infantile cortical hyperostosis (mandible involved)
Hypervitaminosis D
= excessive ingestion of vitamin D (large doses act like parathormone)
loss of appetite, diarrhea, drowsiness, headaches
polyuria, polydipsia, renal damage
convulsions
excessive phosphaturia (parathormone decreases tubular absorption)
hypercalcemia + hypercalciuria; anemia
deossification widening of provisional zone of calcification cortical + trabecular thickening alternating bands of increased + decreased density near / in epiphysis (zone of provisional calcification) vertebra outlined by dense band of bone + adjacent radiolucent line within dense calvarium metastatic calcinosis in arterial walls (between age 20 and 30)
kidneys = nephrocalcinosis
periarticular tissue (puttylike)
premature calcification of falx cerebri (most consistent sign!)
Hypoparathyroidism
tetany = hypocalcemic neuromuscular excitability (numbness, cramps, carpopedal spasm, laryngeal stridor, generalized convulsions)
hypocalcemia + hyperphosphatemia
normal / low serum alkaline phosphatase
premature closure of epiphyses hypoplasia of tooth enamel + dentine; blunting of roots generalized increase in bone density in 9%: localized thickening of skull sacroiliac sclerosis bandlike density in metaphysis of long bones (25%), iliac crest, vertebral bodies thickened lamina dura (inner table) + widened diploe deformed hips with thickening + sclerosis of femoral head + acetabulum
@ Soft tissue
intracranial calcifications in basal ganglia, choroid plexus, occasionally in cerebellum calcification of spinal and other ligaments subcutaneous calcifications ossification of muscle insertions ectopic bone formation
P.107
Idiopathic Hypoparathyroidism
= rare condition of unknown cause
round face, short dwarflike, obese
mental retardation
cataracts
dry scaly skin, atrophy of nails
dental hypoplasia (delayed tooth eruption, impaction of teeth, supernumerary teeth)
Secondary Hypoparathyroidism
= accidental removal / damage to parathyroid glands in thyroid surgery / radical neck dissection (5%); I-131 therapy (rare); external beam radiation; hemorrhage; infection; thyroid carcinoma; hemochromatosis (iron deposition)
Hypophosphatasia
= autosomal recessive congenital disease with low activity of serum-, bone-, liver-alkaline phosphatase resulting in poor mineralization (deficient generation of bone crystals)
Incidence: | 1:100,000 |
Histo: | indistinguishable from rickets |
phosphoethanolamine in urine as precursor of alkaline phosphatase
normal serum calcium + phosphorus
GROUP I = neonatal = congenital lethal form
marked demineralization of calvarium ( caput membranaceum = soft skull) lack of calcification of metaphyseal end of long bones streaky irregular spotty margins of calcification cupping of metaphysis angulated shaft fractures with abundant callus formation short poorly ossified ribs poorly ossified vertebrae (especially neural arches) small pelvic bones
OB-US:
high incidence of intrauterine fetal demise increased echogenicity of falx (enhanced sound transmission secondary to poorly mineralized calvarium) poorly mineralized short bowed tubular bones + multiple fractures poorly mineralized spine short poorly ossified ribs polyhydramnios
Prognosis: death within 6 months GROUP II = juvenile severe form
onset of symptoms within weeks to months
moderate / severe dwarfism
delayed weight bearing
resembles rickets separated cranial sutures; craniostenosis in 2nd year
Prognosis: 50% mortality GROUP III = adult mild form
recognized later in childhood / adolescence / adulthood
dwarfism
clubfoot, genu valgum demineralization of ossification centers (at birth / 3 4 months of age): widened metaphyses wormian bones
Prognosis: excellent; after 1 year no further progression GROUP IV = latent form of heterozygous state
normal / borderline levels of alkaline phosphatase
patients are small for age
disturbance of primary dentition
bone fragility + healed fractures enlarged chondral ends of ribs metaphyseal notching of long bones Erlenmeyer flask deformity of femur
Hypothyroidism
Hypothyroidism during Childhood = Cretinism
Frequency: | 1:4,000 live births have congenital hypothyroidism |
Cause: | sporadic hypoplasia / ectopia of thyroid |
delayed skeletal maturation (appearance + growth of ossification centers, epiphyseal closure) fragmented stippled epiphyses wide sutures / fontanels with delayed closure delayed dentition delayed / decreased pneumatization of sinuses + mastoids hypertelorism dense vertebral margins demineralization hypoplastic phalanges of 5th finger MR:
reduced myelination of brain (usually beginning during midgestation)
OB-US:
fetal goiter (especially in hyperthyroid mothers treated with methimazole / propylthiouracil / I-131)
Hypothyroidism during Adulthood
calvarial thickening / sclerosis wedging of dorsolumbar vertebral bodies coxa vara with flattened femoral head premature atherosclerosis No skeletal changes with adult onset!
Differences between Various Types of Hypothyroidism
HypoPT | Pseudo HypoPT | Pseudopseudo HypoPT | |
---|---|---|---|
Serum Ca | |||
Serum P | |||
AlkaPhos | or | or | |
Response to PTH-Injection | |||
Urine AMP | |||
Urine P | |||
Plasma AMP |
P.108
Infantile Cortical Hyperostosis
= CAFFEY DISEASE
= uncommon self-limiting proliferative bone disease of infancy; remission + exacerbations are common
Cause: ? infectious;? autosomal dominant with variable expression + incomplete penetrance / sporadic occurrence (rare) Age: <6 months, reported in utero; M:F = 1:1 Histo: inflammation of periosteal membrane, proliferation of osteoblasts + connective tissue cells, deposition of immature bony trabeculae sudden, hard, extremely tender soft-tissue swellings over bone
irritability, fever
elevated ESR, increased alkaline phosphatase
leukocytosis, anemia
Location: mandible (80%) > clavicle > ulna + others (except phalanges + vertebrae + round bones of wrists and ankles) Site: hyperostosis affects diaphysis of tubular bones asymmetrically, epiphyses spared massive periosteal new-bone formation + perifocal soft-tissue swelling double-exposed ribs narrowing of medullary space (= proliferation of endosteum) bone expansion with remodeling of old cortex Prognosis: usually complete recovery by 30 months Rx: mild analgesics, steroids
Chronic Infantile Hyperostosis
disease may persist or recur intermittently for years
delayed muscular development, crippling deformities
bowing deformities, osseous bridging, diaphyseal expansion DDx: (1) Hypervitaminosis A (rarely <1 year of age) (2) Periostitis of prematurity
(3) Healing rickets
(4) Scurvy (uncommon <4 months of age)
(5) Syphilis (focal destruction)
(6) Child abuse
(7) Prostaglandin administration (usually following 4 6 weeks of therapy)
(8) Osteomyelitis
(9) Leukemia
(10) Neuroblastoma
(11) Kinky hair syndrome
(12) Hereditary hyperphosphatasia
Iron Deficiency Anemia
Age: | infants affected |
Cause: | (1) inadequate iron stores at birth (2) deficient iron in diet (3) impaired gastrointestinal absorption of iron (4) excessive iron demands from blood loss (5) polycythemia vera (6) cyanotic CHD |
widening of diploe + thinning of tables with sparing of occiput (no red marrow) hair-on-end appearance of skull osteoporosis in long bones (most prominent in hands) absence of facial bone involvement
Jaccoud Arthropathy
After subsidence of frequent severe attacks of rheumatic fever
Path: | periarticular fascial + tendon fibrosis without synovitis |
rheumatic valve disease
Location: | primarily involvement of hands; occasionally in great toe |
muscular atrophy periarticular swelling of small joints of hands + feet ulnar deviation + flexion of MCP joints most marked in 4th + 5th finger NO joint narrowing / erosion
Klinefelter Syndrome
47, XXY (rarely XXYY) chromosomal abnormality
Incidence: | 1:750 live births (probably commonest chromosomal aberration) |
testicular atrophy (hyalinization of seminiferous tubules) = small / absent testes, sterility (azoospermia) eunuchoid constitution: gynecomastia; paucity of hair on face + chest; female pubic escutcheon
mild mental retardation
high level of urinary gonadotropins + low level of 17-ketosteroids after puberty
NO distinctive radiological findings! may have delayed bone maturation failure of frontal sinus to develop small bridged sella turcica scoliosis, kyphosis coxa valga metacarpal sign (short 4th metacarpal) accessory epiphyses of 2nd metacarpal bilaterally
47, XXX = Superfemale Syndrome
usually over 6 feet tall; subnormal intelligence; frequently antisocial behavior
Klippel-Trenaunay Syndrome
= sporadic (nonhereditary) rare mesodermal abnormality that usually affects a single lower limb characterized by a triad of:
port-wine nevus = unilateral large flat infiltrative cutaneous capillary hemangioma often in dermatomal distribution on affected limb; may fade in 2nd 3rd decade
gigantism = overgrowth of distal digits / entire extremity (especially during adolescent growth spurt) involving soft-tissue + bone
varicose veins on lateral aspect of affected limb; usually ipsilateral to hemangioma
P.109
Pathogenesis:
superficial lateral venous channel of large caliber thought to represent the fetal lateral limb bud vein that has failed to regress; tissue overgrowth is secondary to impaired venous return
Age: usually in children; M:F = 1:1 Associated with: polydactyly, syndactyly, clinodactyly, oligodactyly, ectrodactyly, congenital dislocation of hip hemangiomas of colon / bladder (3 10%)
spinal hemangiomas + AVMs
hemangiomas in liver / spleen
lymphangiomas of limb
Location: lower extremity (10 15 more common than upper extremity); bilateral in <5%; extension into trunk may occur extremity pain
spontaneous cutaneous hemorrhage
chronic venous insufficiency
cutaneous lymphatic vesicles, lymphorrhea
elongation of bones: leg length discrepancy increased metatarsal / metacarpal + phalangeal size
cortical thickening soft-tissue hypertrophy (at birth / later in life) punctate calcifications (phleboliths) in pelvis (bowel wall, urinary bladder) pulmonary vein varicosities cystic lung lesions Venogram:
extensive dilation of superficial veins enlarged perforating veins aplasia / hypoplasia of lower extremity veins (18 40%):? selective flow of contrast material up the lateral venous channel may fail to opacify the deep venous system incompetent valveless collateral venous channels (? persistent lateral limb bud vein = Klippel-Trenaunay vein) arises near the ankle + extends a variable distance up the extremity + drains into deep femoral vein / iliac veins (in >66%)
Color Doppler US:
normal deep veins
Lymphangiography:
hypoplasia of lymphatic system
Cx: | thrombophlebitis, deep venous thrombosis, pulmonary embolism, lymphangitis |
Rx: | (1) conservative: application of graded compressive stockings, pneumatic compression devices, percutaneous sclerosis of localized venous malformations / superficial varicosities (2) surgical: epiphysiodesis, excision of soft-tissue hypertrophy, vein stripping |
DDx: | (1) Parke-Weber syndrome = congenital persistence of multiple microscopic AV fistulas + spectrum of Klippel-Trenaunay-Weber syndrome (pulsatility, thrill, bruit) (2) Neurofibromatosis (caf -au-lait spots, axillary freckling, cutaneous neurofibromas, macrodactyly secondary to plexiform neurofibromas, wavy cortical reaction, early fusion of growth plate, limb hypertrophy not as extensive / bilateral) (3) Beckwith-Wiedemann syndrome (aniridia, macroglossia, cryptorchidism, Wilms tumor, broad metaphyses, thickened long-bone cortex, advanced bone age, periosteal new-bone formation, hemihypertrophy) (4) Macrodystrophia lipomatosis (hyperlucency of fat, distal phalanges most commonly affected, overgrowth ceases with puberty, usually limited to digits) (5) Maffucci syndrome (cavernous hemangiomas, soft tissue hypertrophy, phleboliths, multiple enchondromas) |
Labral Tears of Shoulder
Anterior Labral Tear
Location: | anteroinferior labrum > entire anterior labrum > isolated tear of anterosuperior labrum |
Subtypes of anteroinferior labral tears:
Bankart lesion
Anterior labroligamentous periosteal sleeve avulsion
Perthes lesion
absence / detachment of labrum frayed labrum with irregular margin
DDx: | (1) Middle + inferior glenohumeral ligaments closely apposed to anterior labrum (2) Recess between anterior labrum + glenoid rim (3) Recess between middle + inferior ligaments |
Slap Lesion
= anterior-to-posterior lesion of the superior labrum centered at biceps tendon attachment
Mechanism: fall on an outstretched hand (most common), anterior shoulder dislocation, sports activity with overhead arm motion pain, clicking sensation
after fall on outstretched hand (31%) patient usually presents with SLAP III, IV, V lesion
P.110
SLAP I | = | fraying of superior labrum; common in elderly as a degenerative tear |
SLAP II | = | detachment of superior biceps-labral complex from glenoid rim DDx: superior sublabral recess (less distance between labrum + glenoid, no irregular appearance, no lateral extension of defect) |
SLAP III | = | bucket-handle tear of superior labrum leaving biceps tendon attached to glenoid |
SLAP IV | = | bucket-handle tear of superior labrum with tear extending into biceps tendon |
SLAP V | = | Bankart lesion dissecting upward to involve the biceps tendon |
SLAP VI | = | unstable radial / flap tear with separation of biceps anchor |
SLAP VII | = | superior labral tear extending into middle glenohumeral ligament |
SLAP VIII | = | SLAP II + entire posterior labral tear; anterior inferior labrum not involved |
SLAP IX | = | circumferential labral tear |
Superior Labrum Anterior-to-Posterior Lesions |
Langerhans cell histiocytosis
= LCH = HISTIOCYTOSIS X (former name)
= poorly understood group of disorders characterized by proliferation of Langerhans cells (normally responsible for first-line immunologic defense in the skin)
Cause: | uncertain (? primary proliferative disorder possibly due to defect in immunoregulation; neoplasm; virus) |
Path: | influx of eosinophilic leukocytes simulating inflammation; reticulum cells accumulate cholesterol + lipids (= foam cells); sheets or nodules of histiocytes may fuse to form giant cells, cytoplasm contains (? viral) Langerhans bodies |
Histo: | Langerhans cells are similar to mononuclear macrophages + dendritic cells as the two major types of nonlymphoid mononuclear cells involved in immune + nonimmune inflammatory response; derived from promonocytes (= bone marrow stem cell) |
Age: | any age, mostly presenting at 1 4 years; M:F = 1:1 |
Location: | bone + bone marrow, lymph nodes, thymus, ear, liver and spleen, gallbladder, GI tract, endocrine system |
DDx: | osteomyelitis, Ewing sarcoma, leukemia, lymphoma, metastatic neuroblastoma |
Clinical manifestations:
Localized LCH (70%) = eosinophilic granuloma
Disseminated LCH (30%)
Chronic disseminated LCH (20%) = Hand-Sch ller-Christian disease
Fulminant disseminated LCH (10%) = Letterer-Siwe disease
Eosinophilic Granuloma (70%)
= most benign variety of LCH localized to bone
Age: 5 10 years (highest frequency); range 2 30 years; <20 years (in 75%); M:F = 3:2 Path: bone lesions arise within medullary canal (RES) Histo: considerable number of eosinophils in addition to the dominant Langerhans cell constituent painful tender bone lesion + soft-tissue swelling
fever, leukocytosis, elevated sedimentation rate
eosinophilia in blood + CSF
Location: bone (in children) or lung (in adults) Sites: monostotic involvement in 50 75%; (a) flat bones: calvarium > mandible > ribs > pelvis > vertebrae (rarely posterior elements)
(b) long bones: diaphyseal (58%) + metaphyseal (28%) + metadiaphyseal (12%) + epiphyseal (2%) in humerus, femur, tibia
bone lesions 1 15 cm in diameter: geographic / permeative / moth-eaten configuration well- / poorly defined borders DDx: neuroblastoma metastases, leukemia, lymphoma
@ Skull (50%)
Site: diploic space of parietal bone (most commonly involved) + temporal bone (petrous ridge, mastoid) round / ovoid punched-out lesion: DDx: venous lake, arachnoid granulation, parietal foramen, epidermoid cyst, hemangioma beveled edge / hole-within-hole appearance (due to asymmetric destruction of inner + outer tables) sharply marginated without sclerotic rim (DDx: epidermoid with bone sclerosis) sclerotic margin during healing phase (50%)
button sequestrum = remnants of bone as a central bone density within a lytic lesion consisting of erosive accumulation of histiocytes soft-tissue mass overlying the lytic process in calvarium (often palpable) isodense homogeneously enhancing mass in hypothalamus / pituitary gland
@ Orbit
benign focal mass infiltration of orbital bones
@ Mastoid process
intractable otitis media with chronically draining ear (in temporal bone involvement)
destructive lesion near mastoid antrum DDx: mastoiditis, cholesteatoma, metastasis Cx: extension to middle ear may destroy ossicles leading to deafness
@ Jaw
gingival + contiguous soft-tissue swelling floating teeth = destruction of alveolar bone mandibular fracture
@ Axial skeleton (25%)
vertebra plana = coin on edge = Calv disease (6%) = collapse of vertebra (most commonly thoracic): Most common cause of vertebra plana in children preserved disk space rare involvement of posterior elements no kyphosis
lytic lesion in supraacetabular region
@ Proximal long bones (15%)
Site: mostly diaphyseal; epiphyseal lesions are uncommon expansile lytic lesion with ill-defined / sclerotic edges endosteal scalloping, widening of medullary cavity cortical thinning, intracortical tunneling erosion of cortex + soft-tissue mass laminated periosteal reaction (frequent), may show interruptions may appear rapidly within 3 weeks lesions respect joint space + growth plate
@ Lung involvement (20%)
Incidence: 0.05 0.5:100,000 annually Age: peak between 20 and 40 years Strong association between smoking + primary pulmonary Langerhans cell histiocytosis! 3 10 mm nodules reticulonodular pattern with predilection for apices may develop into honeycomb lung recurrent pneumothoraces (25%) rib lesions with fractures (common) pleural effusion, hilar adenopathy (unusual)
NUC:
negative bone scans in 35% (radiographs more sensitive) bone lesions generally not Ga-67 avid Ga-67 may be helpful for detecting nonosseous lesions
P.111
Prognosis: | excellent with spontaneous resolution of bone lesions in 6 18 months |
Hand-Sch ller-Christian Disease (20%)
= chronic disseminated form of LCH characterized by CLASSIC TRIAD (in 10 15%) of
exophthalmos (mass effect on orbital bone)
diabetes insipidus (basilar skull disease / direct infiltration of posterior pituitary gland)
destructive bone lesions (often of calvaria)
Path: proliferation of histiocytes, may simulate Ewing sarcoma Age at onset: <5 years (range from birth to 40 years); M:F = 1:1 diabetes insipidus (30 50%) often with large lytic lesion in sphenoid bone / panhypopituitarism
otitis media with mastoid + inner ear invasion
exophthalmos (33%), sometimes with orbital wall destruction
generalized eczematoid skin lesions (30%)
ulcers of mucous membranes (gingiva, palate)
Sites: bone, liver, spleen, lymph nodes, skin @ Bone
osteolytic skull lesions with overlying soft-tissue nodules geographic skull = ovoid / serpiginous destruction of large area floating teeth with mandibular involvement destruction of petrous ridge + mastoids + sella turcica
@ Orbit
diffuse orbital disease with multiple osteolytic bone lesions
@ Liver
hepatosplenomegaly (rare) scattered echogenic / hypoattenuating liver granuloma lymphadenopathy (may be massive) gallbladder wall thickening (from infiltration)
@ Lung
cyst + bleb formation with spontaneous pneumothorax (25%) ill-defined diffuse nodular infiltration often progressing to fibrosis + honeycomb lung
@ Thymus
enlarged thymus + punctate calcifications
Prognosis: spontaneous remissions + exacerbations; fatal in 15%
Letterer-Siwe Disease (10%)
= acute disseminated, fulminant form of LCH characterized by wasting, pancytopenia (from bone marrow dysfunction), generalized lymphadenopathy, hepatosplenomegaly
Incidence: 1: 2,000,000 Age: several weeks after birth to 2 years Path: generalized involvement of reticulum cells; may be confused with leukemia hemorrhage, purpura (secondary to coagulopathy)
severe progressive anemia / pancytopenia
intermittent fever
failure to grow / malabsorption + hypoalbuminemia
skin rash: scaly erythematous seborrhea-like brown to red papules
Location: especially pronounced behind ears, in axillary, inguinal, and perineal areas Sites: liver, spleen, bone marrow, lymph nodes, skin hepatosplenomegaly + lymphadenopathy (most often cervical) obstructive jaundice @ Bone involvement (50%):
widespread multiple lytic lesions; raindrop pattern in calvarium
Prognosis: | rapidly progressive with 70% mortality rate |
Lateral Epicondylitis
= Tennis Elbow = tendinitis (epicondylitis is a misnomer)
= chronic overuse syndrome involving origin of extensor carpi radialis brevis tendon
Age: 35 50 years Cause: tennis, throwing sports, swimming, carpentry, plumbing (repetitive forearm pronation + supination with wrist extension) pain + tenderness in region of lateral epicondyle radiating into forearm
Histo: tendon microtears followed by formation of angiofibrotic hyperplasia (= noninflammatory reactive tissue) MR (oblique coronal images):
focally hyperintense signal compared with muscle + less intense than fluid on all sequences
P.112
Rx: | (1) conservative management: avoidance of painful activity, application of ice, NSAID (2) splints, steroid injection (3) excision of abnormal tissue + decortication of epicondyle + reattachment of tendon |
DDx of painful elbow: | injury to radial collateral ligament / extensor carpi radialis longus tendon, cartilage defect |
Laurence-Moon-Biedl Syndrome
retardation
obesity
hypogonadism
craniosynostosis polysyndactyly
Lead Poisoning
= PLUMBISM
Path: lead concentrates in metaphyses of growing bones (distal femur > both ends of tibia > distal radius) leading to failure of removal of calcified cartilaginous trabeculae in provisional zone loss of appetite, vomiting, constipation, abdominal cramps
peripheral neuritis (adults), meningoencephalitis (children)
anemia
lead line at gums (adults)
bands of increased density at metaphyses of tubular bones (only in growing bone) lead lines may persist clubbing if poisoning severe (anemia) bone-in-bone appearance
DDx: | (1) Healed rickets (2) Normal increased density in infants <3 years of age |
Leprosy
= HANSEN DISEASE
Organism: Mycobacterium leprae Types:
lepromatous: in cutis, mucous membranes, viscera
neural: enlarged indurated nodular nerve trunks; anesthesia, muscular atrophy, neurotrophic changes
mixed form
@ Osseous changes (in 15 54% of patients)
specific signs: Location: center of distal end of phalanges / eccentric ill-defined areas of decalcification, reticulated trabecular pattern, small rounded osteolytic lesions, cortical erosions joint spaces preserved healing phase: complete resolution / bone defect with sclerotic rim + endosteal thickening nasal spine absorption + destruction of maxilla, nasal bone, alveolar ridge enlarged nutrient foramina in clawlike hand erosive changes of ungual tufts
nonspecific signs: soft-tissue swelling; calcification of nerves contractures / deep ulcerations neurotrophic joints (distal phalanges in hands, MTP in feet, Charcot joints in tarsus)
Leukemia of Bone
A. CHILDHOOD
Most common malignancy of childhood:
1/3 of all pediatric malignancies
Histo:
Acute Lymphocytic Leukemia (ALL in 75%)
most often in children <5 years of age
lymph node enlargement rare
Acute Myelogenous Leukemia (AML)
tends to affect older children + adolescents
lymph node enlargement common
migratory paraarticular arthralgias (25 50%) due to adjacent metaphyseal lesions (may be confused with acute rheumatic fever / rheumatoid arthritis)
low-grade fever, bruising, fatigue
bone pain (due to increased intraosseous pressure from proliferation of malignant cells)
elevated erythrocyte sedimentation rate, anemia
hepatosplenomegaly, occasionally lymphadenopathy
Peripheral blood smears may be negative in aleukemic form! Skeletal manifestations in 50 90%:
Location: proximal + distal metaphyses of long bones, flat bones, spine Diffuse osteopenia (most common pattern)
diffuse demineralization of spine + long bones (= leukemic infiltration of bone marrow + catabolic protein / mineral metabolism) coarse trabeculation of spongiosa (due to destruction of finer trabeculae) multiple biconcave / partially collapsed vertebrae (14%)
Leukemic lines (40 53% in acute lymphoblastic leukemia):
transverse radiolucent metaphyseal bands, uniform + regular across the width of metaphysis (= leukemic infiltration of bone marrow / osteoporosis at sites of rapid growth) Location: large joints (proximal tibia, distal femur, proximal humerus, distal radius + ulna) horizontal / curvilinear bands in vertebral bodies + edges of iliac crest dense metaphyseal lines after treatment
Focal destruction of flat / tubular bones:
multiple small clearly defined ovoid / spheroid osteolytic lesions (destruction of spongiosa, later cortex) in 30 60% moth-eaten appearance, sutural widening, prominent convolutional markings of skull Lytic lesions distal to knee / elbow in children are suggestive of leukemia (rather than metastases)!
Isolated periostitis of long bones (infrequent):
smooth / lamellated / sunburst pattern of periosteal reaction (cortical penetration by sheets of leukemic cells into subperiosteum) in 12 25%
Metaphyseal osteosclerosis + focal osteoblastic lesion (very rare)
osteosclerotic lesions (late in disease due to reactive osteoblastic proliferation) mixed lesions (lytic + bone-forming) in 18%
Dx: sternal marrow / peripheral blood smear Cx: proliferation of leukemic cells in marrow leads to extraskeletal hematopoiesis DDx: metastatic neuroblastoma, Langerhans cell histiocytosis
P.113
B. ADULTHOOD
Death usually occurs before skeletal abnormalities manifest osteoporosis solitary radiolucent foci (vertebral collapse) permeating radiolucent mottling (proximal humerus)
MR:
diffuse decrease in signal intensity compared with normal marrow on T1WI isointense / mildly hyperintense compared with normal marrow on T2WI (due to high water content of leukemic cells + displacement of fat) abnormally hyperintense relative to normal marrow on STIR
Lipoblastoma
= rare benign postnatal proliferation of mesenchymal cells with a spectrum of differentiation ranging from prelipoblasts (spindle cells) to mature adipocytes
Types: (a) lipoblastoma = circumscribed encapsulated form (2/3) (b) lipoblastomatosis = diffuse infiltrative form (1/3)
Incidence: 30% of adipose-derived tumors in children Path: encapsulated immature adipose tissue (embryonal fat) separated by septa into multiple lobules Histo: uni- and multivacuolated lipoblasts interspersed between spindle / stellate mesenchymal cells; suspended in myxoid stroma Age: <3 years of age (in >90%); M:F = 2:1 Location: subcutaneous tissue of extremities, neck, trunk, perineum, retroperitoneum Size: 3 5 cm gradually increasing painless soft-tissue mass
CT:
tumor of fat density separated by fibrous septa intratumoral fat stranding NO enhancement
MR:
high signal intensity on T1WI + T2WI heterogeneous texture ascribed to excessive amount of immature fat + myxoid tissue, intratumoral infarction, extensive mucoid, cystic degeneration areas of increased intensity after fat suppression (DDx to lipoma)
Rx: | complete excision with tendency to recur in 10 25% |
DDx: | liposarcoma (extremely rare in children), dermoid cyst |
Lipoma of Bone
= INTRAOSSEOUS LIPOMA
Incidence: <1:1,000 primary bone tumors Age: any (4th 6th decade); M:F = 1:1 May be associated with: hyperlipoproteinemia asymptomatic / localized bone pain
Location: calcaneus, extremities (proximal femur > tibia, fibula, humerus), ilium, skull, mandible, maxilla, ribs, vertebrae, sacrum, coccyx, radius Site: metaphysis expansile nonaggressive radiolucent lesion loculated / septated appearance (trabeculae) thin well-defined sclerotic border thinned cortex (NO cortical destruction) NO periosteal reaction may contain clump of calcification centrally (= dystrophic calcification from fat necrosis) VIRTUALLY DIAGNOSTIC: @ Calcaneus
in triangular region between major trabecular groups (LAT projection) calcified / ossified nidus
@ Proximal femur
on / above intertrochanteric line marked ossification of margins of lesion
Radiographic appearance similar to unicameral bone cyst (infarcted lipoma = unicameral bone cyst?)
DDx: | fibrous dysplasia, simple bone cyst, posttraumatic cyst, giant cell tumor, desmoplastic fibroma, chondromyxoid fibroma, osteoblastoma |
Lipoma of Soft Tissue
Most common mesenchymal tumor composed of mature adipose tissue
Histo: | mature fat cells (adipocytes) that are uniform in size + shape, occasionally have fibrous connective tissue as septations; fat unavailable for systemic metabolism |
stable size after initial period of discernible growth
Age: 5th 6th decade; M > F Location:
superficial = subcutaneous lipoma (more common) in posterior trunk, neck, proximal extremities
deep lipoma in retroperitoneum, mediastinum, chest wall, deep soft tissue of hands + feet; multiple in 5 7% (up to several hundred tumors)
mass of fat opacity / density / intensity identical to subcutaneous fat cortical thickening (with adjacent parosteal lipoma) CT:
well-defined + homogeneous tumor with low attenuation coefficient ( 65 to 120 HU) no enhancement following IV contrast material
MR:
well-defined + homogeneous, often with septations signal intensity characteristics similar to subcutaneous fat: hyperintense on T1WI + moderately intense on T2WI thin septations of low signal intensity (not uncommon) correspond to fibrous connective tissue differentiation from other lesions by fat suppression technique
Angiolipoma
= lesion composed of fat separated by small branching vessels
P.114
Age: 2nd + 3rd decade; 5% familial incidence tender
Location: upper extremity, trunk signal characteristics of fat + mixed with varying numbers of large / small vessels mostly encapsulated lesion, may infiltrate
Benign Mesenchymoma
= long-standing lipoma with chondroid + osseous metaplasia
Infiltrating Lipoma
= INTRAMUSCULAR LIPOMA
= relatively common benign lipomatous tumor extending between muscle fibers that become variably atrophic
Peak age: | 5th 6th decade; M > F |
Location: | thigh (50%), shoulder, upper arm |
Lipoma Arborescens
= DIFFUSE SYNOVIAL LIPOMA
= lipoma-like lesion composed of hypertrophic synovial villi distended with fat, probably reactive process to chronic synovitis
Location: | knee; monoarticular |
Frequently associated with: | degenerative joint disease, chronic rheumatoid arthritis, prior trauma |
Neural Fibrolipoma
= FIBROLIPOMATOUS HAMARTOMA OF NERVE
= rare tumorlike condition characterized by sausage-shaped / fusiform enlargement of a nerve by fibrofatty tissue
Age: early adulthood before age 30 years / at birth Histo: infiltration of epineurium + perineurium by fibrofatty tissue with separation of nerve bundles soft slowly enlarging mass
pain, tenderness, decreased sensation, paresthesia
Location: volar aspect of hand, wrist, forearm Site: median n. (most frequently), ulnar n., radial n., brachial plexus; May be associated with: macrodactyly (in 2/3) = macrodystrophia lipomatosa may not be visible radiographically MR:
longitudinally oriented, cylindrical, linear / serpiginous structures of signal void about 3 mm in diameter (= nerve fascicles with epi- and perineural fibrosis) separated by areas of fat signal intensity (= mature fat infiltrating the interfascicular connective tissue)
US:
cablelike appearance = alternating hyper- and hypoechoic bands on US
DDx: | cyst, ganglion, lipoma, traumatic neuroma, plexiform neurofibroma, vascular malformation |
Liposarcoma
Malignant tumor of mesenchymal origin with bulk of tumor tissue differentiating into adipose tissue
Incidence: 12 18% of all malignant soft-tissue tumors; 2nd most common soft-tissue sarcoma in adults (after malignant fibrous histiocytoma) Age: 5th 6th decade Histo:
rarely arising from lipoma
myxoid type (most common, in 40 50%): varying degrees of mucin + fibrous tissue + relatively little lipid (<10%) = intermediate differentiation
radiodensity between water + muscle
lipogenic type: malignant lipoblasts with large amounts of lipid + scanty myxoid matrix = well-differentiated
radiodensity of fat with thick + poorly defined streaks of high attenuation
pleomorphic type (least common): marked cellular pleomorphism, paucity of lipid + mucin
= highly undifferentiated
radiodensity of muscle (no distinguishing imaging features from other soft-tissue sarcomas)
usually painless mass (may be painful in 10 15%)
Location: lower extremity (45%), abdominal cavity + retroperitoneum (14%), trunk (14%), upper extremity (7.6%), head & neck (6.5%), miscellaneous (13.5 %) Spread: hematogenous to lung, visceral organs; myxoid liposarcoma shows tendency for serosal + pleural surfaces, subcutaneous tissue, bone nonspecific soft-tissue mass (frequently fat is radiologically not detectable) inhomogeneous mass with soft-tissue + fatty components enhancement after IV contrast material (contradistinction to lipoma) concomitant mass in retroperitoneum / thigh (in up to 10% of myxoid liposarcomas) as multicentric lesion / metastasis mass of near water density / hypoechoic / hypointense on T1WI + hyperintense on T2WI in myxoid liposarcoma (high content of myxoid cells)
Lyme Arthritis
Agent: | spirochete Borrelia burgdorferi; transmitted by tick Ixodes dammini |
Histo: | inflammatory synovial fluid, hypertrophic synovia with vascular proliferation + cellular infiltration |
history of erythema chronicum migrans
endemic areas: Lyme, Connecticut, first recognized location; now also throughout United States, Europe, Australia
recurrent attacks of arthralgias within days to 2 years after tick bite (80%)
Location: mono- / oligoarthritis of large joints (especially knee) erosion of cartilage / bone (4%) Rx: antibiotics DDx: (1) Rheumatic fever (2) Rheumatoid arthritis
(3) Gonococcal arthritis
(4) Reiter syndrome
Lymphangioma
= sequestered noncommunicating lymphoid tissue lined by lymphatic endothelium
Cause: congenital obstruction of lymphatic drainage Subtypes:
Capillary lymphangioma (rare)
Location: subcutaneous tissue Cavernous lymphangioma
Location: about the mouth + tongue Cystic lymphangioma (most common)
= cystic hygroma
Associated with: hydrops fetalis, Turner syndrome Location: head, neck (75%), axilla (20%), extension into mediastinum (3 10%) soft fluctuant mass
Lymphangiomas are frequently a mixture of subtypes!
P.115
Age: | found at birth (50 65%); within first 2 years of life (90%) |
Location: | soft tissue; bone (rare) |
multilocular cystic lesion with fibrous septations occasionally serpentine vascular channels opacification during lymphangiography / direct puncture clear / milky fluid on aspiration DDx: hemangioma (blood on aspiration)
Lymphangiomatosis of bone
= MASSIVE OSTEOLYSIS = GORHAM-Stout DISEASE = VANISHING BONE DISEASE = PHANTOM BONE Disease
= infrequent disorder of bone + soft tissues secondary to persistence of dilated lymphatics from 14 20th week EGA
Incidence: >100 cases described Histo: massive proliferation of hemangiomatous / lymphangiomatous tissue with large sinusoid spaces + fibrosis Age: infants + children, M=F Associated with: cystic hygroma (neck, axilla, chest wall, mediastinum), splenic cysts, chylothorax, soft-tissue hemangiomas without calcifications frequently history of severe trauma (50%) little / no pain
Location: any bone (frequently multiple locations); most commonly major long bones (humerus, shoulder, mandible), pelvis, spine, thorax, short tubular bones of hand + feet (unusual) progressive relentless resorption / destruction of bone: patchy osteopenia (early) expanding intramedullary lesion (later) complete resorption of entire bone segments (late)
lack of reaction (no periosteal reaction, minimal sclerosis) advancing edge of destruction not sharply delineated tapering margins of bone ends at sites of osteolysis with conelike spicule of bone (early changes) no respect for joints DDx: Langerhans cell histiocytosis, fibrous dysplasia, brown tumor of hyperparathyroidism
Lymphoma of Bone
= RETICULUM CELL SARCOMA = HISTIOCYTIC LYMPHOMA = PRIMARY LYMPHOMA OF BONE
= singular bone lesion
the generalized form of reticulum cell sarcoma is lymphoma Prevalence: 5% of all primary bone tumors; <1% of all NHL; 2 6% of all primary malignant bone tumors in children Incidence of bone marrow involvement:
5 15% in Hodgkin disease;
25 40% in non-Hodgkin lymphoma
Bone marrow involvement indicates progression of disease Bone marrow imaging-guidance for biopsy! NUC: 40% sensitivity; 88% specificity MR: 65% sensitivity; 90% specificity
Histo: mostly large B-cell category; sheets of reticulum cells, larger than those in Ewing sarcoma (DDx: myeloma, inflammation, osteosarcoma, eosinophilic granuloma) Age: bimodal distribution with peaks in 2nd 3rd and 5th 6th decades; 50% <40 years; 35% <30 years; M:F = 2:1 chronic dull pain
striking contrast between size of lesion + patient's well-being
Location: lower femur, upper tibia (40% about knee), humerus, pelvis, scapula, ribs, vertebra Site: dia- / metaphysis cancellous bone erosion (earliest sign) mottled permeative pattern of separate coalescent areas late cortical destruction lamellated / sunburst periosteal response (rare and less than in Ewing sarcoma) lytic / reactive new-bone formation associated soft-tissue mass without calcification (70%) synovitis of knee joint common Cx: pathologic fracture (most common among malignant bone tumors) Prognosis: 54% 5-year survival DDx: (1) Osteosarcoma (less medullary extension, younger patients) (2) Ewing tumor (systemic symptoms, debility, younger patients)
(3) Metastatic malignancy (multiple bones involved, more destructive)
Macrodystrophia Lipomatosa
= rare nonhereditary congenital form of localized gigantism = neural fibrolipoma with macrodactyly
Path: striking increase in adipose tissue in a fine fibrous network involving periosteum, bone marrow, nerve sheath, muscle, subcutaneous tissue May be associated with: syn-, clino-, polydactyly painless
Location: 2nd or 3rd digit of hand / foot; unilateral; one / few adjacent digits may be involved in the distribution of the median / plantar nerves long + broad splayed phalanges with endosteal + periosteal bone deposition overgrowth of soft tissue, greatest at volar + distal aspects slanting of articular surfaces lucent areas of fat (DIAGNOSTIC) Prognosis: accelerated maturation possible; growth stops at puberty DDx: fibrolipomatous hamartoma associated with macrodystrophia lipomatosa (indistinguishable), Klippel-Trenaunay-Weber syndrome, lymphangiomatosis, hemangiomatosis, neurofibromatosis, chronic vascular stimulation, Proteus syndrome
Marfan Syndrome
= ARACHNODACTYLY
= autosomal dominant familial disorder of connective tissue with high penetrance but extremely variable expression, new mutations in 15%
P.116
Etiology: fibrillin gene defect on chromosome 15 resulting in abnormal cross-linking of collagen fibers Prevalence: 5:100,000; M:F = 1:1 A. MUSCULOSKELETAL MANIFESTATIONS
tall thin stature with long limbs, arm span greater than height
muscular hypoplasia + hypotonicity
scarcity of subcutaneous fat (emaciated look)
generalized osteopenia @ Skull
elongated face
dolichocephaly prominent jaw high arched palate
@ Hand
Steinberg sign = protrusion of thumb beyond the confines of the clenched fist (found in 1.1% of normal population)
metacarpal index (averaging the 4 ratios of length of 2nd through 5th metacarpals divided by their respective middiaphyseal width) >8.8 (male) or 9.4 (female)
arachnodactyly = elongation of phalanges + metacarpals flexion deformity of 5th finger
@ Foot
pes planus clubfoot hallux valgus hammer toes disproportionate elongation of 1st digit of foot
@ Spine
ratio of measurement between symphysis and floor + crown and floor >0.45
pectus carinatum / excavatum (common) scoliosis / kyphoscoliosis (45 60%) increased incidence of Scheuermann disease and spondylosis dural ectasia increased interpedicular distance posterior scalloping presacral + lateral sacral meningoceles expansion of sacral spinal canal enlargement of sacral foramina winged scapulae
@ Joints
ligamentous laxity + hypermobility + instability
premature osteoarthritis patella alta genu recurvatum recurrent dislocations of patella, hip, clavicle, mandible slipped capital femoral epiphysis progressive protrusio acetabuli (50%), bilateral > unilateral, F > M
B. OCULAR MANIFESTATIONS
bilateral ectopia lentis, usually upward + outward (secondary to poor zonular attachments)
glaucoma, macrophthalmia
hypoplasia of iris + ciliary body
contracted pupils (absence of dilator muscle)
myopia, retinal detachment
strabismus, ptosis
blue sclera
megalocornea = flat enlarged thickened cornea
C. CARDIOVASCULAR MANIFESTATIONS (60 98%)
affecting mitral valve, ascending aorta, pulmonary artery, splenic + mesenteric arteries (occasionally)
Cause of death in 93%! chest pain, palpitations, shortness of breath, fatigue
mid-to-late systolic murmur + one / more clicks
Associated with: congenital heart defect (33%) incomplete coarctation, ASD @ Aorta (cause of death in 55%)
Histo: myxomatous degeneration of aortic annulus tulip bulb aorta = symmetrical dilatation of aortic sinuses of Valsalva slightly extending into ascending aorta (58%) annuloaortic ectasia = combination of aortic root dilatation + aortic regurgitation fusiform aneurysm of ascending aorta, rarely beyond innominate artery (due to cystic medial necrosis) aortic wall calcification rare Cx: (1) Aortic regurgitation (in 81% if root diameter >5 cm; in 100% if root diameter >6 cm (2) Aortic dissection
(3) Aortic rupture (secondary to progressive aortic root dilatation)
@ Mitral valve
Histo: myxomatous degeneration of valve leads to redundancy + laxness mid-to-late systolic murmur + one / more clicks
floppy valve syndrome (95%) = redundant chordae tendineae with mitral valve prolapse + regurgitation Cx: (1) Mitral regurgitation (2) Rupture of chordae tendineae (rare)
@ Coarctation (mostly not severe)
@ Pulmonary artery aneurysm + dilatation of pulmonary arterial root (43%)
@ Cor pulmonale (secondary to chest deformity)
D. PULMONARY MANIFESTATIONS
cystic lung disease recurrent spontaneous pneumothoraces
E. ABDOMINAL MANIFESTATION
recurrent biliary obstruction DDx: (1) Homocystinuria (osteoporosis) (2) Ehlers-Danlos syndrome
(3) Congenital contractural arachnodactyly (ear deformities, NO ocular / cardiac abnormalities)
(4) Type III MEN (medullary thyroid carcinoma, mucosal neuromas, pheochromocytoma, marfanoid habitus)
Melorheostosis
Nonhereditary disease of unknown etiology; often incidental finding
P.117
Age: slow chronic course in adults; rapid progression in children Associated with: osteopoikilosis, osteopathia striata, tumors / malformations of blood vessels (hemangioma, vascular nevi, glomus tumor, AVM, aneurysm, lymphedema, lymphangiectasia) severe pain + limited joint motion (bone may encroach on nerves, blood vessels, or joints)
thickening + fibrosis of overlying skin (resembling scleroderma)
muscle atrophy (frequent)
Location: diaphysis, usually monomelic with at least two bones involved in dermatomal distribution (follows spinal sensory nerve sclerotomes); entire cortex / limited to one side of cortex; more common in lower limb; skull, spine, ribs rarely involved candle wax dripping = continuous / interrupted streaks / blotches of sclerosis along tubular bone beginning at proximal end extending distally with slow progression may cross joint with joint fusion small opacities in scapula + hemipelvis (similar to osteopoikilosis) discrepant limb length flexion contractures of hip + knee genu valgum / varus dislocated patella ossified soft-tissue masses (27%) DDx: (1) Osteopoikilosis (generalized) (2) Fibrous dysplasia (normal bone structure not lost, not as dense)
(3) Engelmann disease
(4) Hyperostosis of neurofibromatosis, tuberous sclerosis, hemangiomas
(5) Osteoarthropathy
Orientation of Meniscal Tears |
Meniscal Tear
Cause: | acute injury, degeneration related to aging |
Type of cross-sectional tear pattern:
vertical tear with longitudinal / radial / oblique surface pattern
horizontal tear with longitudinal / oblique / cleavage surface pattern
mixed pattern
Type of arthroscopic surface pattern:
LONGITUDINAL TEAR
= tear oriented parallel to outer margin of meniscus
(a) vertical tear
full-thickness tear = extension to inferior + superior surfaces
partial-thickness tear = extension only to one surface
Rx: may be amenable to repair if (a) in vascularized outer 3 5 mm
(b) between 7 and 40 mm long
(c) no degenerative changes
1. Single peripheral longitudinal vertical tear
Cause: traumatic vertical tear in peripheral third of meniscus
2. Bucket handle tear
= longitudinal vertical tear with unstable displaced inner fragment (= handle of bucket)
Cause: traumatic Age: frequently in young individuals Frequency: 9 19% of symptomatic patients; 10% of all meniscal tears Associated with: ACL injury in up to 40% locked knee, lack of full knee extension
Site: medial: lateral meniscus = 2 3:1 absent bow-tie sign (sagittal image) = peripheral image fails to demonstrate normal bow-tie configuration on >2 consecutive images (71 98% sensitive, 63% specific) hypoplastic / truncated anterior + posterior horns on sagittal image double PCL sign (sagittal image) = meniscal fragment displaced into notch between PCL and medial tibial eminence oriented parallel to PCL (>98% specific, 27 44% sensitive, 93% PPV) fragment-in-notch sign (coronal image) = displaced fragment in intercondylar notch flipped meniscus sign Rx: arthroscopic / surgical repair
3. Broken bucket-handle tear
4. Double / triple vertical longitudinal bucket-handle tear
(b) horizontal tear (Cleavage Tear)
= divides meniscus in superior + inferior fragments
Cause: usually degenerative Associated with: meniscal cyst Site: primarily involving the central horizontal plane of meniscus beginning at inner margin Rx: partial meniscectomy
RADIAL TEAR = TRANSVERSE TEAR (6%)
= vertical tear perpendicular to free edge of meniscus; may extend partially / completely through the meniscus to its outer circumference
tears <3 mm may be asymptomatic
Site: posterior + mid third of lateral meniscus usually seen on only 1 image blunting of the inner margin of meniscus (if image plane parallel to tear) poorly defined meniscus with diffusely increased signal intensity (if tear extends to outer margin) normal meniscus in adjacent sections discrete vertical focus of increased signal intensity (if image plane perpendicular to tear) Cx: lack of resistance to hoop stresses Rx: partial resection often necessary 1. Parrot beak tear
= free edge tear with vertical + horizontal component
Cause: usually degenerative Site: in body of lateral meniscus near the junction of body + posterior horn fraying of free edge
2. Root tear
= tear in anterior / posterior horn
P.118
OBLIQUE / FLAP TEAR
= composite of a radial tears that curves into a longitudinal tear
Cause: traumatic, at times degenerative Frequency: most common type of tear Site: common in midportion of medial meniscus both horizontal and vertical components commonly extending to inferior surface of meniscus Rx: partial meniscectomy Distinctive Meniscal Tear Patterns
MR Classification of Meniscal Injury
Grade Type MR Finding PPV for Tear 0 0 normal meniscus 1% 1 I globular / punctate intrameniscal signal 2% 2 II linear signal not extending to surface 5% III short tapered apex of meniscus 23% IV truncated / blunted apex of meniscus 71% 3 V signal extending to only one surface 85% 3 VI signal extending to both surfaces 95% 3 VII comminuted reticulated signal pattern 82%
MENISCOCAPSULAR SEPARATION
= Peripheral Tear
= tearing of peripheral attachments of meniscus
linear region of fluid separating meniscus from capsule uncovering of a portion of tibial plateau owing to inward movement of separated meniscus
Site of injury:
medial meniscus in 45%: no isolated tears of body / anterior horn
lateral meniscus in 22%: posterior horn involved in 80% of all lateral meniscal tears
both menisci involved in 33%
Associated with: | ligamentous injury |
asymptomatic in up to 20% of older individuals
MR:
direct signs:
signal extending to articular surface: 2 images with signals contacting the surface (95% PPV) 1 image with signal to surface (33% PPV) Diagnosis of tear hinges on surface involvement! Intrameniscal signal may be a sign of myxoid degeneration
normal collagen bundles
persistent vascularity in children + young adults
contusion
Truncation artifact + magic angle artifact may cause increased intrameniscal signal!
distortion of meniscal shape
indirect signs
parameniscal cyst (meniscal tear in 98 100%) posterior lip medial tibial plateau bone bruise (64% PPV for meniscal tear mostly in periphery) torn popliteomeniscal fascicle (79% PPV)
MR sensitivity, specificity, and accuracy:
Tear of Sensitivity Specificity Accuracy Medial meniscus 95% 88% 59 92% Lateral meniscus 81% 96% 87 92% Anterior cruciate lig. 91 96% Posterior cruciate lig. up to 99% MR has a high negative predictive value! 60 97% accuracy for arthrography 84 99% accuracy for arthroscopy (poor at posterior horn of medial meniscus)
Interpretative errors (12% for experienced radiologist):
Lateral meniscus: 5.0% FN (middle + posterior horn) 1.5% FP (posterior horn)
Medial meniscus: 2.5% FN (posterior horn) 2.5% FP (posterior horn)
PITFALLS:
Normal variants simulating tears:
Superior recess on posterior horn of medial meniscus
Popliteal hiatus
hiatus of popliteal tendon separates lateral meniscus from joint capsule Seen above posterior aspect of lateral meniscus on most superficial sagittal slice! Tendon moves behind + inferior to meniscus on adjacent deeper sections!
P.119
Transverse ligament
Course: connects anterior horns of both menisci overrides superior aspect of menisci before completely fusing to menisci Trace the cross section of the transverse ligament through the infrapatellar fat pad on more central images!
Meniscofemoral ligaments
Origin: superior + medial aspect of posterior horn of lateral meniscus Attachment: medial femoral condyle demonstrated in 1/3 of cases on SAG images (a) Wrisberg ligament
posterior to posterior cruciate ligament
(b) Humphrey ligament
anterior to posterior cruciate ligament Finding usually limited to single most medial image!
Soft tissue between capsule + medial meniscus
Healed meniscus
persistent grade 3 signal at least up to 6 months S/P meniscectomy (false-positive type IV finding)
Degenerative changes
grade 1 signal = globular increase in intensity grade 2 signal = linear signal not extending to articular surface
Diskoid meniscus
= abnormally shaped enlarged diskus-like meniscus
Prevalence: in 1.5 3% for lateral meniscus; 0.12 0.3% for medial meniscus Age: children, adolescents Side: lateral: medial meniscus = 10:1 >2 bowtie slices on sagittal image >15 mm width on coronal image centrally displaced fragment with meniscus apparently of normal size (coronal images)
Mesomelic Dwarfism
= heritable bone dysplasia with shortening of intermediate segments (radius + ulna or tibia + fibula)
A. Langer type autosomal recessive
mental impairment
mesomelic shortening of limbs hypoplasia of ulna + fibula hypoplasia of mandible with short condyles
B. Nievergelt type autosomal dominant
severe mesomelic shortening of lower limbs marked thickening of tibia + fibula in central portion clubfoot (frequent)
C. Reinhardt type: autosomal dominant
D. Robinow type: autosomal dominant
E. Werner type: autosomal dominant
F. Lamy-Bienenfeld type autosomal dominant
ligamentous laxity
shortening of radius + ulna + tibia absent fibula normal femur + humerus shortening of all long bones at birth, most marked in tibia + radius modeling deformity with widening of diaphysis mild to moderate bowing hypoplasia of fibula with absent lateral malleolus short + thick ulna with hypoplastic distal end Madelung deformity of wrist hypoplasia of a vertebral body may be present
Metaphyseal Chondrodysplasia
= severe short-limbed dwarfism
metaphyseal flaring (Erlenmeyer flask deformity) extending into diaphysis A. Schmid type (most common)
autosomal dominant
waddling gate
Distribution: more marked in lower limbs; mild involvement of hands + wrists shortened bowed long bones widened epiphyseal growth plates irregular widened cupped metaphyses coxa vara genu varum DDx: vitamin D refractory rickets
B. McKusick type
autosomal recessive (eg, in Amish)
sparse brittle hair, deficient pigmentation
normal intelligence
shortening of long bones with normal width cupped + widened metaphyses with lucent defects short middle phalanges + narrow distal phalanges becoming triangular and bullet-shaped (more frequent in hands than feet) widened costochondral junctions + cystic lucencies
C. Jansen type (less common)
sporadic occurrence with wide spectrum
intelligence normal / retarded
serum calcium levels often elevated
Distribution: symmetrical involvement of all long + short tubular bones widened epiphyseal plates expanded irregular + fragmented metaphyses (unossified cartilage extending into diaphyses) DDx: rickets
D. Pyle disease = Metaphyseal dysplasia
often tall
often asymptomatic
Distribution: major long bones, tubular bones of hands, medial end of clavicle, sternal end of ribs, innominate bone splaying of proximal + distal ends of long bones with thinned cortex relative constriction of central portion of shafts craniofacial hyperostosis genu valgum
Metastases to Bone
15 100 times more common than primary skeletal neoplasms!
P.120
Frequency:
If primary known | If primary unknown | ||
---|---|---|---|
Breast | 35% | Prostate | 25% |
Prostate | 30% | Lymphoma | 15% |
Lung | 10% | Breast | 10% |
Kidney | 5% | Lung | 10% |
Uterus | 2% | Thyroid | 2% |
Stomach | 2% | Colon | 1% |
Others | 13% |
SOLITARY BONE LESION
Of all causes only 7% are due to metastasis In patients with known malignancy solitary bone lesions are due to metastasis (55%), due to trauma (25%), due to infection (10%)
Location: | axial skeleton (64 68%), ribs (45%), extremities (24%), skull (12%) |
mnemonic: | Several Kinds Of Horribly Nasty Tumors Leap Promptly To Bone |
Sarcoma, Squamous cell carcinoma
Kidney tumor
Ovarian cancer
Hodgkin disease
Neuroblastoma
Testicular cancer
Lung cancer
Prostate cancer
Thyroid cancer
Breast cancer
Breast cancer: | extensive osteolytic lesions; involvement of entire skeleton; pathologic fractures common |
Thyroid / kidney: | often solitary; rapid progression with bone expansion (bubbly); frequently associated with soft-tissue mass (distinctive) |
Rectum / colon: | may resemble osteosarcoma with sunburst pattern + osteoblastic reaction |
Hodgkin tumor: | upper lumbar + lower thoracic spine, pelvis, ribs; osteolytic / occasionally osteoblastic lesions |
Osteosarcoma: | 2% with distant metastases, adjuvant therapy has changed the natural history of the disease in that bone metastases occur in 10% of osteosarcomas without metastases to the lung |
Ewing sarcoma: | extensive osteolytic / osteoblastic reaction (13% with distant metastases) |
Neuroblastoma: | extensive destruction, resembles leukemia (metaphyseal band of rarefaction), mottled skull destruction + increased intracranial pressure, perpendicular spicules of bone |
Mode of spread: | through bloodstream / lymphatics / direct extension |
Location: | predilection for marrow-containing skeleton (skull, spine, ribs, pelvis, humeri, femora) |
single / multiple lesions of variable size usually nonexpansile joint spaces + intervertebral spaces preserved (cartilage resistant to invasion)
Osteolytic Bone Metastases
Most common cause: | neuroblastoma (in childhood); lung cancer (in adult male); breast cancer (in adult female), thyroid cancer; kidney; colon |
may begin in spongy bone (associated with soft tissue mass in ribs) vertebral pedicles often involved (not in multiple myeloma)
Osteoblastic Bone Metastases
= evidence of slow-growing neoplasm
Primary: prostate, breast, lymphoma, malignant carcinoid, medulloblastoma, mucinous adenocarcinoma of GI tract, TCC of bladder, pancreas, neuroblastoma Most common cause: prostate cancer (in adult male); breast cancer (in adult female) mnemonic: 5 Bees Lick Pollen Brain (medulloblastoma)
Bronchus
Breast
Bowel (especially carcinoid)
Bladder
Lymphoma
Prostate
frequent in vertebrae + pelvis may be indistinguishable from Paget disease
Mixed Bone Metastases
breast, prostate, lymphoma
Expansile / Bubbly Bone Metastases
kidney, thyroid
Permeative Bone Metastases
Burkitt lymphoma, mycosis fungoides
Bone Metastases with Sunburst Periosteal Reaction
(infrequent)
prostatic carcinoma, retinoblastoma, neuroblastoma (skull), GI tract
Bone Metastases with Soft-tissue Mass
thyroid, kidney
Calcifying Bone Metastases
mnemonic: | BOTTOM |
Breast
Osteosarcoma
Testicular
Thyroid
Ovary
Mucinous adenocarcinoma of GI tract
Skeletal Metastases in Children
Neuroblastoma (most often): diffuse / focal
Lymphoma
Rhabdomyosarcoma
Ewing sarcoma
Retinoblastoma
Hepatoma
P.121
Skeletal Metastases in Adult
mnemonic: | Common Bone Lesions Can Kill The Patient |
Colon
Breast
Lung
Carcinoid
Kidney
Thyroid
Prostate
Role of Bone Scintigraphy in Bone Metastases
Pathophysiology: | accumulation of tracer at sites of reactive bone formation |
False-negative scan: | very aggressive metastases |
False-positive scan: | degeneration, healing fractures, metabolic disorders |
Baseline bone scan:
high sensitivity for many metastatic tumors to bone (particularly carcinoma of breast, lung, prostate); 5% of metastases have normal scan; 5 40% occur in appendicular skeleton
substantially less sensitive than radiographs in infiltrative marrow lesions (multiple myeloma, neuroblastoma, histiocytosis)
screening of asymptomatic patients
useful in: prostate cancer, breast cancer
not useful in: non small-cell bronchogenic carcinoma, gynecologic malignancy, head and neck cancer
multiple asymmetric areas of increased uptake axial > appendicular skeleton (dependent on distribution of bone marrow); vertebrae, ribs, pelvis involved in 80% superscan in diffuse bony metastases
Follow-up bone scan:
stable scan = suggestive of relatively good prognosis increased activity in: enlargement of bone lesions / appearance of new lesions indicate progression of the disease
healing flare phenomenon (in 20 61%) = transient increase in lesion activity secondary to healing under antineoplastic treatment concomitant with increased sclerosis, detected at 3.2 1.4 months after initiation of hormonal / chemotherapy, of no additional favorable prognostic value
avascular necrosis particularly in hips, knees, shoulders caused by steroid therapy
osteoradionecrosis / radiation-induced osteosarcoma
decreased activity in: predominately osteolytic destruction
metastases under radiotherapy; as early as 2 4 months with minimum of 2000 rads
DDx: | pulmonary metastasis (SPECT helpful in distinguishing nonosseous lung from overlying rib uptake) |
Role of Bone Scan in Breast Cancer
Routine preoperative bone scan not justified:
Stage I: unsuspected metastases in 2%, mostly single lesion Stage II: unsuspected metastases in 6% Stage III: unsuspected metastases in 14% Follow-up bone scan:
At 12 months no new cases; at 28 months in 5% new metastases; at 30 months in 29% new metastases
Conversion from normal:
Stage I: in 7% Stage II: in 25% Stage III: in 58% With axillary lymph node involvement conversion rate 2.5 that of those without! Serial follow-up examinations are important to assess therapeutic efficacy + prognosis!
Role of Bone Scan in Prostate Cancer
Stage B: | 5% with skeletal metastases |
Stage C: | 10% with skeletal metastases |
Stage D: | 20% with skeletal metastases |
Test sensitivities for detection of osseous metastases:
scintigraphy 1.0
radiographic survey 0.68
alkaline phosphatase 0.5
acid phosphatase 0.5
Role of Magnetic Resonance Imaging in Bone Metastases
ideal for bone marrow imaging due to high contrast between bone marrow fat + water-containing metastatic deposits
Metastases are most often found in sites of dominant hematopoietic marrow because of its rich vascular supply!
in children: | proximal + distal metaphyses of long bones, flat bones, spine |
in adults: | calvarium, spine, flat bones, proximal humeral + femoral metaphyses |
Focal lytic lesion (usual):
hypointense on T1WI (more conspicuous when surroundings contain large number of fat cells) hyperintense on T2WI / STIR (due to increased water content of hypercellular tumor tissue) occasionally surrounded by mild edema
Focal sclerotic lesion
(eg, medulloblastoma, retinoblastoma):
hypointense on T1WI + T2WI (bone production)
Diffuse heterogeneous lesions (eg, neuroblastoma):
inhomogeneously hypointense on T1WI + hyperintense on T2WI
Diffuse homogeneous lesions:
homogeneously hypointense on T1WI + hyperintense on T2WI
Metatrophic Dysplasia
= HYPERPLASTIC ACHONDROPLASIA = METATROPHIC DWARFISM
metatrophic = changeable (change in proportions of trunk to limbs over time secondary to developing kyphoscoliosis in childhood)
longitudinal double skin fold overlying coccyx
long bones short with dumbbell-like / trumpet-shaped configuration (exaggerated metaphyseal flaring) hourglass phalanges (short with widened ends) wide separation of major joint spaces (thick articular cartilage) delayed ossification of flat irregular epiphyses
P.122
@ Chest
cylindrical narrowed elongated thorax short + wide ribs pectus carinatum
@ Vertebrae
odontoid hypoplasia with atlantoaxial instability progressive kyphoscoliosis platyspondyly + very wide intervertebral spaces wedge- / keel-shaped vertebral bodies
@ Pelvis
coccygeal appendage similar to a tail (rare but CHARACTERISTIC) short squared iliac bones + irregular acetabula narrowed greater sciatic notch
Prognosis: | compatible with life, increased disability from kyphoscoliosis |
DDx: | achondroplasia, mucopolysaccharidoses |
Methotrexate Osteopathy
= syndrome that consists of
bone pain
osteopenia
pathologic fractures
Methotrexate
= dihydrofolate reductase inhibitor most often used in children for treatment of ALL / osteosarcoma / brain tumor
Radiographic findings similar to scurvy: osteopenia dense provisional zones of calcification pathologic fractures (most often metaphyseal) sharply outlined epiphyses NO massive subperiosteal hemorrhage impaired healing of fractures
Morton Neuroma
= INTERDIGITAL NEUROMA
Age: highest prevalence in 5th + 6th decade; M:F = 1:4 Path: perineural fibrosis entrapping a plantar digital nerve; neuroma is a misnomer Often associated with: intermetatarsal bursitis Histo: dense collagenous + fibrous tissue numbness; burning / tingling electric forefoot pain increasing with activity + wearing of narrow shoes
Mulder sign = painful palpable click when metatarsal heads are squeezed together with one hand + involved metatarsal space simultaneously compressed between thumb and index finger of the other hand
Location: plantar side of deep transverse intermetatarsal ligament Site: typically 2nd / 3rd intermetatarsal space (rarely 1st / 4th) MR (87% sensitive, 100% specific):
small well-demarcated teardrop-shaped mass isointense to muscle on T1WI + hypointense to fat on T2WI fluid in intermetatarsal bursa Best depicted prone (positional changes) fluid in intermetatarsal bursa (vertically oriented between metatarsal heads)
Rx: | conservative treatment; surgical excision for neuromas >5 mm in transverse diameter (more commonly symptomatic) |
Mucopolysaccharidoses
= lysosomal storage disorder from deficiency of specific lysosomal enzymes involved in degradation of mucopolysaccharides
Types:
Type I = Hurler
Type II = Hunter
Type III = Sanfilippo
Type IV = Morquio (most common)
Type V = Scheie
Type VI = Maroteaux-Lamy
Type VII = Sly
All autosomal recessive except for Hunter (X-linked)! Associated with: valvular heart disease corneal clouding
retardation (prominent in types I, II, III, VII)
skeletal involvement dominates in types IV and VI
scaphocephaly, macrocephaly; thick calvarium; hypertelorism platyspondyly with kyphosis + dwarfism irregularity at anterior aspect of vertebral bodies atlantoaxial subluxation + instability (laxity of transverse ligament / hypoplasia or absence of odontoid) limb contractures broad hands + brachydactyly hepatosplenomegaly
@ Brain
brain atrophy varying degree of hydrocephalus multiple white matter changes within cerebral hemispheres (diffuse hypodense areas, prolongation of T1 + T2)
Cx: | cord compression at atlantoaxial joint (types IV + VI) |
Dx: | combination of clinical features, radiographic abnormalities correlated with genetic + biochemical studies |
Prenatal Dx: | occasionally successful analysis of fibroblasts cultured from amniotic fluid |
DDx: | Gaucher disease, Niemann-Pick disease |
Hurler Syndrome
= GARGOYLISM = PFAUNDLER-HURLER DISEASE
= MPS I-H
= autosomal recessive disease
Cause: homozygous for MPS III gene with excess chondroitin sulfate B due to deficient X-L iduronidase (= Hurler corrective factor) Incidence: 1:10,000 births Age: usually appears >1st year dwarfism
progressive mental deterioration after 1 3 years
large head; sunken bridge of nose; hypertelorism
early corneal clouding progressing to blindness
gargoyle features = everted lips + protruding tongue
teeth widely separated + poorly formed
progressive narrowing of nasopharyngeal airway
protuberant abdomen (secondary to dorsolumbar kyphosis + hepatosplenomegaly)
urinary excretion of chondroitin sulfate B (dermatan sulfate) + heparan sulfate
P.123
Mucopolysaccharidoses
Type Eponym Inheritance Enzyme Deficiency Urinary Glycosaminoglycan Neurologic Signs I-H Hurler autosomal recessive alpha-L-iduronidase dermatan sulfate marked II Hunter X-linked recessive iduronate sulfatase dermatan / heparan sulfate mild to moderate III Sanfilippo autosomal recessive heparan sulfate mental deterioration A heparan sulfate sulfatase B N-acetyl-alpha-D-glucosaminidase C alpha-glucosamine-N-acetyl-transferase D N-acetylglucosamine-6-sulfate sulfatase IV Morquio autosomal recessive N-acetylgalactosamine-6-sulfate sulfatase keratan sulfate none A D beta-galactosidase I-S(V) Scheie autosomal recessive alpha-L-iduronidase heparan sulfate none VI Maroteaux-Lamy autosomal recessive arylsulfatase B dermatan sulfate none VII Sly autosomal recessive beta-glucuronidase dermatan / heparan sulfate variable Reilly bodies (metachromic granules) in white blood cells or bone marrow cells
@ Skull (earliest changes >6 months of age)
frontal bossing calvarial thickening premature fusion of sagittal + lambdoid sutures deepening of optic chiasm enlarged J-shaped sella (undermining of anterior clinoid process) small facial bones wide mandibular angle + underdevelopment of condyles communicating hydrocephalus
@ Extremities
thick periosteal cloaking of long-bone diaphyses (early changes) swelling / enlargement of diaphyses + cortical thinning (due to dilatation of medullary canal) + tapering of either end: distal humerus, radius, ulna, proximal ends of metacarpals deossification with heterogeneous bone density + course trabeculation (due to deposition of accumulated precursor metabolites in bone marrow) flexion deformities of knees + hips trident hands; clawing (occasionally) delayed maturation of irregular carpal bones
@ Spine
thoracolumbar kyphosis with lumbar gibbus oval centra with normal / increased height + anterior beak at T12/L1/L2 long slender pedicles proximally long slender ribs at level of neck + wide distally = spatulate rib configuration
@ Pelvis
widely flared iliac wings with inferior tapering constriction of iliac bones coxa valga
Prognosis: | death by age 10 15 years |
Morquio Syndrome
= KERATOSULFATURIA = MPS IV (most common type)
= autosomal recessive; excess keratosulfate
Incidence: | 1:40,000 births |
Etiology: | N-acetyl-galactosamine-6-sulfatase deficiency resulting in defective degradation of keratin sulfate (mainly in cartilage, nucleus pulposus, cornea) |
Age: | normal at birth; skeletal changes manifest within first 18 months; M:F = 1:1 |
excessive urinary excretion of keratan sulfate
normal intelligence
muscular weakness + hypotonia
ligamentous laxity, but joint stiffness
short-trunk dwarfism (<4 feet tall)
head thrust forward + sunken between high shoulders
corneal clouding evident around age 10
progressive deafness
coarse face with short nose, broad mouth, widely spaced teeth with thin enamel
semicrouching stance + knock knees from flexion deformities of knees + hips
@ Skull
mild dolichocephaly hypertelorism poor mastoid air cell development short nose + depression of bridge of nose prominent maxilla
P.124
@ Chest
increased AP diameter + marked pectus carinatum (horizontal protuberant sternum) slight lordosis with wide short ribs bulbous costochondral junctions failure of fusion of sternal segments
@ Spine
hypoplasia / absence of odontoid process of C2 C1-C2 instability with anterior (life-threatening) atlantoaxial subluxation + progressive disabling myelopathy thick C2-body with narrowing of vertebral canal atlas close to occiput / posterior arch of C1 within foramen magnum platyspondyly = universal vertebra plana esp. affecting lumbar spine by age 2 3 years (DDx: normal height in Hurler syndrome) ovoid vertebral bodies with central anterior beak / tongue at lower thoracic / upper lumbar vertebrae mild gibbus at thoracolumbar transition = low dorsal kyphosis exaggerated lumbar lordosis widened intervertebral disk spaces
@ Pelvis
goblet-shaped / wineglass pelvis = constricted iliac bodies + elongated pelvic inlet + broad flat flared iliac wings oblique hypoplastic acetabular roofs
@ Femur
initially well-formed femoral head epiphysis, then involution + fragmentation by age 3 6 years lateral subluxation of femoral heads; later hip dislocation wide femoral neck + coxa valga deformity
@ Tibia
delayed ossification of lateral proximal tibial epiphysis sloping of superior margin of tibia plateau laterally + severe genu valgum
@ Hand & foot
short bones of forearm with widening of proximal ends delayed appearance + irregularity of carpal centers small irregular carpal bones proximally pointed short metacarpals 2 5 enlarged joints; hand + foot deformities (flat feet) ulnar deviation of hand
Cx: | cervical myelopathy (traumatic quadriplegia / leg pains / subtle neurologic abnormality) most common cause of death secondary to C2 abnormality; frequent respiratory infections (from respiratory paralysis) |
Rx: | early fusion of C1 C2 |
Prognosis: | may live to adulthood (3rd 4th decade) |
DDx: | (1) Hurler syndrome (normal / increased vertebral height; vertebral beak inferior) |
(2) Spondyloepiphyseal dysplasia (autosomal dominant, present at birth, absent flared ilia / deficient acetabular ossification, small acetabular angle, deficient ossification of pubic bones, varus deformity of femoral neck, minimal involvement of hand + foot, myopia) |
Multiple Epiphyseal Dysplasia
= FAIRBANK DISEASE
=? tarda form of chondrodystrophia calcificans congenita
mild limb shortening irregular mottled calcifications of epiphyses (in childhood + adolescence) epiphyseal irregularities + premature degenerative joint disease, especially of hips (in adulthood) short phalanges
DDx: | Legg-Perthes disease, hypothyroidism |
Multiple Myeloma
= malignancy characterized by monoclonal proliferation of malignant plasma cells
Most common primary malignant neoplasm in adults! Histo: normal / pleomorphic plasma cells (not pathognomonic), may be mistaken for lymphocytes (lymphosarcoma, reticulum cell sarcoma, Ewing tumor, neuroblastoma) (a) diffuse infiltration: myeloma cells intimately admixed with hematopoietic cells (b) tumor nodules: displacement of hematopoietic cells by masses entirely composed of myeloma cells Age: usually 5th 8th decade; 98% >40 years; rare <30 years of age; M:F = 2:1 (a) DISSEMINATED FORM: >40 years of age (98%); M:F = 3:2 (b) SOLITARY FORM: mean age 50 years bone pain (68%)
normochromic normocytic anemia (62%)
RBC rouleau formation
renal insufficiency (55%)
hypercalcemia (30 50%)
proteinuria (88%)
Bence Jones proteinuria (50%)
increased globulin production (monoclonal gammopathy)
Location:
DISSEMINATED FORM:
scattered; axial skeleton predominant site; vertebrae (50%) > ribs > skull > pelvis > long bones (distribution correlates with normal sites of red marrow)
SOLITARY PLASMACYTOMA OF BONE:
vertebrae > pelvis > skull > sternum > ribs
SPINAL PLASMA CELL MYELOMA
sparing of posterior elements (no red marrow) (DDx: metastatic disease) paraspinal soft-tissue mass with extradural extension scalloping of anterior margin of vertebral bodies (osseous pressure from adjacent enlarged lymph nodes)
generalized osteopenia only (15%) with accentuation of trabecular pattern, especially in spine (early) punched out appearance of widespread osteolytic lesions (skull, long bones) with endosteal scalloping and of uniform size diffuse osteolysis (pelvis, sacrum) expansile osteolytic lesions (ballooning) in ribs, pelvis, long bones soft-tissue mass adjacent to bone destruction (= extrapleural + paraspinal mass adjacent to ribs / vertebral column) periosteal new-bone formation exceedingly rare involvement of mandible (rarely affected by metastatic disease) sclerosis may occur after chemotherapy, radiotherapy, fluoride administration sclerotic form of multiple myeloma (1 3%) solitary sclerotic lesion: frequently in spine
diffuse sclerosis
Associated with POEMS syndrome: Polyneuropathy
Organomegaly
Endocrine abnormalities
Myeloma, sclerotic
Skin changes
MR (recognition dependent on knowledge of normal range of bone marrow appearance for age):
hypointense multiple focal areas on T1WI (25%) hyperintense multiple focal areas on T2WI (53%) absence of fatty infiltration (nonspecific)
SENSITIVITY OF BONE SCANS VS. RADIOGRAPHS
Radiographs: in 90% of patients and 80% of sites Bone scan: in 75% of patients and 24 54% of sites Gallium scan: in 55% of patients and 40% of sites 30% of lesions only detected on radiographs 10% of lesions only detected on bone scans Cx: (1) Renal involvement frequent (2) Predilection for recurrent pneumonias (leukopenia) (3) Secondary amyloidosis in 6 15% (4) Pathologic fractures occur often Prognosis: 20% 5-year survival; death from renal insufficiency, bacterial infection, thromboembolism
DDx:
with osteopenia:
Postmenopausal osteoporosis
Hyperparathyroidism
with lytic lesion:
Metastatic disease
Amyloidosis
Myeloid metaplasia
with sclerotic lesion:
Osteopoikilosis
Lymphoma
Osteoblastic metastasis
Mastocytosis
Myelosclerosis
Fluorosis
Lymphoma
Renal osteodystrophy
P.125
Myelomatosis
generalized deossification without discrete tumors vertebral flattening
Musculotendinous Injury
Muscle Contusion
Cause: | direct trauma, usually by blunt object |
Site: | deep within muscle belly |
injury at point of impact
NO architectural changes feathery appearance of diffuse muscle edema increased muscle girth deep intramuscular hematoma (with severe trauma resulting in disruption of muscle fibers)
Myotendinous Strain
Cause: | single traumatic event from excessive stretching |
Susceptibility factors:
muscle composed of (fast contracting) type II fibers
fusiform shape of muscle
extension across two joints
superficial location of muscle
eccentric muscle action
Site: myotendinous junction (= weakest point of musculotendinous unit)
Classification:
1 degree = stretch injury (some fiber disruptions)
no loss of muscle function
Path: interstitial edema + hemorrhage at myotendinous junction with extension into adjacent muscle fibers feathery appearance of muscle
2 degree = partial tear without retraction
mild loss of muscle function
hematoma at myotendinous junction perifascial fluid collection
3 degree = complete rupture
complete loss of muscle function
retracted muscle tendon hematoma at myotendinous junction
Acute Avulsion Injury
Cause: | forceful unbalanced often eccentric muscle contraction |
Path: | periosteal stripping with hematoma at tendon attachment site |
Site: | at tendon insertion |
loss of function, severe tenderness
waviness + retraction of the torn end of tendon with fragment of bone / cartilage
Myelofibrosis
= MYELOSCLEROSIS = AGNOGENIC MYELOID METAPLASIA = MYELO-PROLIFERATIVE SYNDROME = PSEUDOLEUKEMIA
= hematologic disorder of unknown etiology with gradual replacement of bone marrow elements by fibrotic tissue
Characterized by:
extramedullary hematopoiesis
progressive splenomegaly
anemia
variable changes in number of granulocytes + platelets; often predated by polycythemia vera
Cause:
primary: rare in children
secondary: radiation therapy / chemotherapy for leukemia or lymphoma or metastatic disease; Gaucher disease
Age: usually >50 years Path: fibrous / bony replacement of bone marrow; extramedullary hematopoiesis Associated with: metastatic carcinoma, chemical poisoning, chronic infection (TB), acute myelogenous leukemia, polycythemia vera, McCune-Albright syndrome, histiocytosis
dyspnea, weakness, fatigue, weight loss, hemorrhage
normochromic normocytic anemia; polycythemia may precede myelosclerosis in 59%
dry marrow aspirate
Location: red marrow containing bones in 40% (thoracic cage, pelvis, femora, humeral shafts, lumbar spine, skull, peripheral bones) splenomegaly widespread diffuse increase in density (ground glass) jail-bar ribs sandwich / rugger jersey spine generalized increase in bone density in skull + obliteration of diploic space; scattered small rounded radiolucent lesions; or combination of both MR:
hypointense marrow on T1WI + T2WI signal intensity slightly higher than muscle on STIR
NUC:
diffuse increased uptake of bone tracer in affected skeleton, possibly superscan increased uptake at ends of long bones
P.126
DDx: | (1) With splenomegaly: chronic leukemia, lymphoma, mastocytosis |
(2) Without splenomegaly: osteoblastic metastases, fluorine poisoning, osteopetrosis, chronic renal disease |
Myeloid Depletion
= APLASTIC ANEMIA
Cause: idiopathic;? sequelae of viral infection, medication, toxin, chemo- / radiation therapy Path: normal marrow replaced by fat cells MR:
high signal intensity on T1WI low signal intensity on fat-suppressed T2WI Best seen in areas with high percentage of hematopoietic marrow: proximal femoral metaphyses, spine
Myeloproliferative Disorders
= autonomous clonal disorder initiated by an acquired pluripotential hematopoietic stem cell
Types:
Polycythemia vera
Chronic granulomatous leukemia = chronic myelogenous leukemia
Essential idiopathic thrombocytopenia
Agnogenic myeloid metaplasia (= primary myelofibrosis + extramedullary hematopoiesis in liver + spleen)
Pathophysiology:
self-perpetuating intra- and extramedullary hematopoietic cell proliferation without stimulus
trilinear panmyelosis (RBCs, WBCs, platelets)
myelofibrosis with progression to myelosclerosis
myeloid metaplasia = extramedullary hematopoiesis (normocytic anemia, leukoerythroblastic anemia, reticulocytosis, low platelet count, normal / reduced WBC count)
Myositis Ossificans
= PSEUDOMALIGNANT OSSEOUS TUMOR OF SOFT TISSUE = EXTRAOSSEOUS LOCALIZED NONNEOPLASTIC BONE AND CARTILAGE FORMATION = MYOSITIS OSSIFICANS CIRCUMSCRIPTA = HETEROTOPIC OSSIFICATION
= benign solitary self-limiting ossifying soft-tissue mass typically occurring within skeletal muscle
Myositis is a misnomer for lack of inflammation! Cause: direct trauma (75%), paralysis, burn, tetanus, intramuscular hematoma, spontaneous Age: adolescents, young athletic adults; M > F Path: lesion rimmed by compressed fibrous connective tissue + surrounded by atrophic skeletal muscle (myositis = misnomer since no primary inflammation of muscle present) Histo:
early: focal hemorrhage + degeneration + necrosis of damaged muscle; histiocytic invasion; central nonossified core of proliferating benign fibroblasts + myofibroblasts; mesenchymal cells enclosed in ground substance assume characteristics of osteoblasts with subsequent mineralization + peripheral bone formation
intermediate age (3 6 weeks): zone phenomenon with central area of cellular variation and atypical mitotic figures (impossible to differentiate from soft-tissue sarcoma); middle zone of immature osteoid; outer zone of well-formed mature trabeculated dense bone
pain, tenderness, soft-tissue mass
Location: large muscles of extremities (80%) within muscle: anterolateral aspect of thigh + arm; temporal muscle; small muscles of hands; gluteal muscle; rider's bone (adductor longus); fencer's bone (brachialis); dancer's bone (soleus); breast, elbow, knee
periosteal at tendon insertion: Pellegrini-Stieda disease (in / near medial (tibial) collateral ligament of knee) as a result of Stieda fracture (= avulsion injury from medial femoral condyle at origin of tibial collateral ligament)
[Augusto Pellegrini (1877 1958), surgeon in Florence, Italy]
[Alfred Stieda (1869 1945), surgeon in K nigsberg, Germany]
faint calcifications develop in 2 6 weeks after onset of symptoms well-defined partially ossified soft-tissue mass apparent by 6 8 weeks, becoming smaller + mature by 5 6 months radiolucent zone separating lesion from bone (DDx: periosteal sarcoma on stalk) periosteal reaction CT:
well-defined mineralization at periphery of lesion after 4 6 weeks + less distinct lucent center (DDx: sarcoma with ill-defined periphery + calcified ossific center) diffuse ossification in mature lesion
MR:
initially heterogeneous muscle edema progression to masslike region of high-signal intensity on T2WI (during first days to weeks after injury) P.127
Early phase:
mass with poorly defined margins inhomogeneously hyperintense to fat on T2WI isointense to muscle on T1WI contrast enhancement
Intermediate phase:
isointense / slightly hyperintense core on T1WI, increasing in intensity on T2WI rim of curvilinear areas of decreased signal intensity surrounding the lesion (= peripheral mineralization / ossification) increased peritumoral signal intensity on T2WI (= edema of diffuse myositis) focal signal abnormality within bone marrow (= marrow edema)
Mature phase:
well-defined inhomogeneous mass with signal intensity approximating fat decreased signal intensity surrounding lesion + within (dense ossification + fibrosis, hemosiderin from previous hemorrhage)
NUC:
intense tracer accumulation on bone scan (directly related to deposition of calcium in damaged muscle) in phase of mature ossification activity becomes reduced + surgery may be performed with little risk of recurrence
Angio:
diffuse tumor blush + fine neovascularity in early active phase avascular mass in mature healing phase Prognosis: ? resorption in 1 year
DDx:
In early stages difficult to differentiate histologically + radiologically from soft-tissue sarcomas! (1) Osteosarcoma Synovial sarcoma
Fibrosarcoma
Chondrosarcoma
Rhabdomyosarcoma
Parosteal sarcoma (usually metaphyseal with thick densely mineralized attachment to bone)
Posttraumatic periostitis (ossification of subperiosteal hematoma with broad-based attachment to bone)
Acute osteomyelitis (substantial soft-tissue edema + early periosteal reaction)
Tumoral calcinosis (periarticular calcific masses of lobular pattern with interspersed lucent soft-tissue septa)
Osteochondroma (stalk contiguous with normal adjacent cortex + medullary space)
Myositis Ossificans Variants
Panniculitis Ossificans
Location: | subcutis of mostly upper extremities |
less prominent zoning phenomenon
Fasciitis Ossificans
Location: | fascia |
Fibroosseous Pseudotumor of Digits
= FLORID REACTIVE PERIOSTITIS
= nonneoplastic solitary self-limiting process of unknown pathogenesis, probably related to trauma
Age: mean age of 32 years (range 4 64 years); M:F = 1:2 fusiform soft-tissue swelling / mass
Location: predominantly tubular bones of hand + foot: fingers (2nd > 3rd > 5th) Site: proximal > distal > middle phalanx radiopaque soft-tissue mass with radiolucent band between mass + cortex visible calcifications (50%) focal periosteal thickening (50%) cortical erosion (occasionally)
Rx: | local excision |
DDx: | parosteal / periosteal osteogenic sarcoma, peripheral chondrosarcoma, periosteal chondroma, soft-tissue chondroma |
Nail-patella syndrome
= FONG DISEASE = ILIAC HORNS = FAMILIAL / HEREDITARY OSTEO-ONYCHODYSPLASIA = OSTEO-ONYCHODYSOSTOSIS = HOOD SYNDROME = ELBOW-PATELLA SYNDROME
= rare autosomal dominant disorder characterized by symmetrical meso- and ectodermal anomalies
Etiology: ? enzymatic defect in collagen metabolism Age: evident in 2nd + 3rd decades aplasia / hypoplasia of thumb + index fingernails
bilateral spooning / splitting / ridging of fingernails
abnormal gait
abnormal pigmentation of iris
renal dysfunction (secondary to abnormal glomerular basement membrane): proteinuria, hematuria, failure later in life
bilateral posterior iliac horns in 80% (occasionally capped by an epiphysis) DIAGNOSTIC flared iliac crest with protuberant anterior iliac spines genu valgum due to asymmetrical development of femoral condyles prominent tibial tubercles fragmentation / hypoplasia / absence of patella; frequently with recurrent lateral dislocations radial head / capitellum hypoplasia with subluxation / dislocation of radial head dorsally and increased carrying angle of elbow (DDx: congenital dislocation of radial head) clinodactyly of 5th finger short 5th metacarpal flexion contractures of hip, knee, elbow, fingers, foot deltoid, triceps, quadriceps hypoplasia mandibular cysts (occasionally) scoliosis renal osteodystrophy
DDx: | (1) Seckel syndrome = bird-headed dwarfism |
(2) Popliteal pterygium syndrome (absence of patella, toenail dysplasia) |
Necrotizing Fasciitis
Incidence: | 500 cases in literature |
Age: | 58 14 years; M>F |
Cause: | deep internal infection / malignancy (perforated duodenal ulcer / retroperitoneal appendix, retroperitoneal / perirectal infection, infiltrating rectal / sigmoid carcinoma |
Predisposed: | patients with diabetes, cancer, alcohol / drug abuse, poor nutrition |
Organism: | Staphylococcus, E. coli, Bacteroides, Streptococcus, Peptostreptococcus, Klebsiella, Proteus, C. perfringens (5 15%) (multiple organisms in 75%) |
Histo: | necrotic superficial fascia, leukocytic infiltration of deep fascial layers; fibrinoid thrombosis of arterioles + venules with vessel wall necrosis; microbial infiltration of destroyed fascia |
P.128
indolent (1 21 days delay before diagnosis)
nonspecific symptoms: severe pain, fever, leukocytosis, shock, altered mental status
crepitus (50%), overlying skin may be completely intact
Location: lower extremity, arm, neck, back, male perineum / scrotum (= Fournier gangrene) asymmetric fascial thickening with fat stranding (80%) from fluid gas in soft-tissues dissecting along fascial planes from gas-forming organisms (in 55%) associated deep abscess (35%) secondary muscle involvement
Prognosis: | poor with delay in diagnosis |
Rx: | extensive surgical d bridement |
DDx: | (1) Myonecrosis (infection originating in muscle) |
(2) Fasciitis-panniculitis syndromes (chronic swelling of skin + underlying soft tissues + fascial planes in arm + calf) | |
(3) Soft-tissue edema of CHF / cirrhosis (symmetrical diffuse fat stranding) |
Neuropathic Osteoarthropathy
= Neurotrophic Joint = Charcot Joint = Osteoarthritis with a vengeance
= progressive degenerative + destructive joint disorder in patients with abnormal pain sensation + proprioception
Cause:
Congenital
Myelomeningocele
Congenital indifference to pain = asymbolia
Familial dysautonomia (Riley-Day syndrome)
Hereditary sensory and motor neuropathy (Charcot-Marie-Tooth disease)
Acquired
central neuropathy
Injury to brain / spinal cord
Syringomyelia (in 1/3 of patients): shoulder, elbow
Neurosyphilis = tabes dorsalis (in 15 20% of patients): hip, knee, ankle, tarsals
Spinal cord tumors / infection
Extrinsic compression of spinal cord
Multiple sclerosis
Alcoholism
peripheral neuropathy
Diabetes mellitus (most common cause, although incidence low): midfoot, tarsometatarsal joints (middle cuneiform + base of 2nd metatarsal bone first affected), intertarsal joints, subtalar joints, metatarsophalangeal joints, ankle
Peripheral nerve injury
Peripheral nerve tumor
Leprosy (Hansen disease)
Poliomyelitis
others
Scleroderma, Raynaud disease, Ehlers-Danlos syndrome
Rheumatoid arthritis, psoriasis
Amyloid infiltration of nerves, adrenal hypercorticism
Uremia
Pernicious anemia
Iatrogenic
Prolonged use of pain-relieving drugs
Intraarticular / systemic steroid injections
mnemonic: DS6 Diabetes
Syphilis
Steroids
Spinal cord injury
Spina bifida
Syringomyelia
Scleroderma
Pathophysiology:
Loss of proprioception with sensory deficits arising in the spinal cord / peripheral nerves
Neurotraumatic theory
= repetitive trauma with absence of normal protective sensory feedback
Neurovascular theory
= absence of neural stimuli leads to a loss of sympathetic tone resulting in vasodilatation and hyperemia, which promotes bone resorption + weakening of subchondral bone
Pathology:
atrophic pattern (most common):
joint destruction, resorption of fragments (osteoclasts + macrophages remove bone + cartilage debris), dissolution / amputation of periarticular bones, joint effusion
notable absence of osteosclerosis + osteophyte formation
Associated with: syringomyelia, peripheral nerve lesion, also in diabetes Location: non-weight-bearing joints of upper extremity DDx: surgical amputation, septic arthritis
hypertrophic pattern (only sensory nerves affected):
joint destruction, fragmentation of bone, periarticular bony debris
osteosclerosis + osteophyte formation (early, attaining enormous size)
DDx: severe osteoarthritis
mixed pattern
common to both:
joint disorganization, large persistent bloody joint effusion
no history of trauma
swollen + warm joint with normal WBC count + ESR (infection may coexist)
usually painless joint; pain at presentation (in 1/3) with decreased response to deep pain + proprioception
joint changes frequently precede neurologic deficit
synovial fluid: frequently xanthochromic / bloody, lipid crystals (from bone marrow)
persistent joint effusion (first sign) narrowing of joint space speckled calcification in soft tissue (= calcification of synovial membrane) fragmentation of eburnated subchondral bone NO juxtaarticular osteoporosis (unless infected) bag-of-bones appearance in late stage (= marked deformities around joint) mnemonic: 6 Ds Dense subchondral bone (= sclerosis) Degeneration (= attempted repair by osteophytes) Destruction of articular cortex (with sharp margins resembling those of surgical amputation) Deformity ( pencil point deformity of metatarsal heads) Debris (loose bodies) Dislocation (nontraumatic)
subluxation of joints (laxity of periarticular soft tissues) progressive rapid bone resorption joint distension (by fluid, hypertrophic synovitis, osteophytes, subluxation) fracture: healing with exuberant bizarre callus formation MR:
decreased signal intensity in bone marrow on T1WI + T2WI (due to osteosclerotic changes)
@ Shoulder
Cause: syringomyelia, cord trauma with paraplegia shoulder mass (due to fluid distension)
amputated appearance of proximal humerus dislocation large joint effusion fragmented osseous debris in joint capsule + subacromial-subdeltoid bursa DDx: chondrosarcoma
@ Hands + feet
Cause: leprosy (due to trauma + secondary bacterial infection) claw hand / claw toes licked candy cane appearance of metatarsal bone / tapered phalanx (due to concentric bone atrophy with decrease in bone length + width) DDx: diabetes mellitus, frostbite, pernicious anemia, scleroderma, syringomyelia, tabes dorsalis, familial sensory neuropathy
@ Spine (involved in 6 21%)
Cause: traumatic spinal cord injury, inadequately treated syphilis, amyloidosis, congenital insensitivity to pain, diabetes mellitus Site: thoracolumbar junction, lumbar spine disk space narrowing osteolysis / sclerosis of vertebrae + facet joints subluxation abrupt curvature scoliosis paraspinous soft-tissue calcification large hypertrophic beaking endplate osteophytes extensive osseous fragmentation with extension beyond confines of vertebral body margin into paraspinous musculature + into spinal canal DDx: vertebral osteomyelitis, metastasis, granulomatous infection
@ Foot + ankle
Cause: long-term poorly controlled diabetes mellitus, syphilis soft-tissue swelling, warmth, erythema
Site: often begins in midfoot vascular calcifications subluxation (starting at 2nd tarsometatarsal joint) avulsion fracture of posterior tubercle of calcaneus subchondral fracture of head of 2nd metatarsal talonavicular displacement with midfoot arthropathy
P.129
DDx: | osteomyelitis, septic arthritis (usually involve single joint) |
Nodular Tenosynovitis
= GIANT CELL TUMOR OF TENDON SHEATH
= benign proliferative lesion of synovial origin viewed as an extraarticular form of PVNS
Age: young adult Path: very cellular tumor with a capsule that separates the tumor into lobules Histo: multinucleated giant cells, macrophages, fibroblasts, xanthoma cells, varying amounts of hemosiderin Location: hand, occasionally ankle / foot One of the most common tumors of the hand! Site: tendon sheath, joint capsule, bursa, ligament lobulated lesion with well-defined nodules up to 4 cm in size located along tendon sheath (CHARACTERISTIC) bone erosion (15%) MR:
low signal intensity on T1WI + T2WI (hemosiderin deposition) homogeneous contrast enhancement
DDx: | (1) Florid proliferative synovitis (diffuse infiltrative form of GCT = extraarticular subtype of PVNS) |
(2) Pigmented villonodular synovitis | |
(3) Desmoid tumor | |
(4) Malignant fibrous histiocytoma |
Nonossifying Fibroma
= FIBROXANTHOMA = NONOSTEOGENIC FIBROMA = XANTHOMA = XANTHOGRANULOMA OF BONE = FIBROUS METAPHYSEAL-DIAPHYSEAL DEFECT = FIBROUS MEDULLARY DEFECT
Incidence: up to 40% of all children >2 years of age Etiology: lesion resulting from proliferative activity of a fibrous cortical defect that has expanded into medullary cavity Histo: interlacing whorled bundles of spindle-shaped fibroblasts + scattered multinucleated giant cells + foamy xanthomatous cells, variable degree of hemosiderin; usually cellular with only small amounts of collagen Age: 8 20 years; 75% in 2nd decade of life usually asymptomatic; pain if large
Location: shaft of long bone; mostly in bones of lower extremity, especially about knee (distal femur + proximal tibia); distal tibia; fibula Site: eccentric metaphyseal, several cm shaftward from epiphysis, mostly intramedullary, rarely purely diaphyseal multilocular ovoid bubbly osteolytic area alignment along long axis of bone, about 2 cm in length dense sclerotic border toward medulla; V- or U-shaped at one end endosteal scalloping + thinning overlying bulge migrates toward center of diaphysis resolves with age NUC:
minimal / mild uptake on bone scan
MR:
80% hypointense on T1WI + T2WI (extensive hypocellular fibrous tissue, hemosiderin pigment) 20% hypointense on T1WI + hyperintense on T2WI (massive aggregation of foamy histiocytes) peripheral hypointense rim + internal septation (marginal reactive sclerosis + trabeculation) intense contrast enhancement (in 80%) / marginal septal enhancement (in 20%) on T1WI
P.130
CAVE: | lesions >33 mm long involving >50% of the transverse bone diameter need observation |
Prognosis: | spontaneous healing in most cases |
Cx: | (1) Pathologic fracture (not uncommon) |
(2) Hypophosphatemic vitamin D resistant rickets + osteomalacia (tumor may secrete substance that increases renal tubular resorption of phosphorus) | |
DDx: | (1) Adamantinoma (midshaft of tibia) |
(2) Chondromyxoid fibroma (bulging of cortex more striking, hyperintense on T2WI) | |
(3) Fibrous dysplasia (internal septations rare) | |
(4) Aneurysmal bone cyst (heterogeneously hyperintense with fluid-fluid levels) | |
(5) Intraosseous ganglion (hyperintense on T2WI) |
Multiple Fibroxanthomas (in 8 10%)
Associated with: | neurofibromatosis, fibrous dysplasia, Jaff -Campanacci syndrome |
Jaff -Campanacci Syndrome
= nonossifying fibroma with extraskeletal manifestations in children
mental retardation
hypogonadism
ocular defect
cardiovascular congenital defect
caf -au-lait spots
Noonan Syndrome
= PSEUDO TURNER = MALE TURNER SYNDROME
= phenotype similar to Turner syndrome but with normal karyotype (occurs in both males + females)
Striking familial incidence
short / may have normal height
webbed neck
agonadism / normal gonads
delayed puberty
mental retardation
osteoporosis retarded bone age cubitus valgus @ Skull
mandibular hypoplasia with dental malocclusion hypertelorism biparietal foramina dolichocephaly, microcephaly / cranial enlargement webbed neck
@ Chest
sternal deformity: pectus excavatum / carinatum right-sided congenital heart disease (valvar pulmonic stenosis, ASD, eccentric hypertrophy of left ventricle, PDA, VSD) coronal clefts of spine may have pulmonary lymphangiectasis
@ Gastrointestinal tract
intestinal lymphangiectasia eventration of diaphragm renal malrotation, renal duplication, hydronephrosis, large redundant extrarenal pelvis
DDx: | Turner syndrome (mental retardation rare, renal anomalies frequent) |
Ochronosis
= ALKAPTONURIA
= inherited absence of homogentisic acid oxidase with excessive homogentisic acid production + deposition in connective tissue including cartilage, synovium, and bone
Histo: black-pigmented cartilage subject to deterioration resulting in calcification + denudation of cartilaginous tissue M:F = 2:1
black pigment in soft tissues (in 2nd decade): yellowish skin; gray pigmentation of sclera; bluish tinge of ears + nose cartilage
alkaptonuria with black staining of diapers
heart failure, renal failure (pigment deposition)
@ Spine
Age: middle age Site: lumbar region with progressive ascension laminated calcification of multiple intervertebral disks severe narrowing of intervertebral disk space multiple vacuum phenomena (common) osteoporosis of adjoining vertebrae massive osteophytosis + ankylosis of spine (in older patient) spotty calcifications in tissue anterior to vertebral bodies
@ Joints
hypertrophic changes in humeral head severe premature progressive osteoarthritic changes in shoulder, knee, hip, spine of young patients intraarticular osseous bodies small calcifications in paraarticular soft tissues + tendon insertions
Orodigitofacial Syndrome
= OROFACIODIGITAL SYNDROME
= group of heterogeneous defects, probably representing varying expressivity, involving face, oral cavity, and limbs
Etiology: autosomal trisomy of chromosome No. 1 with 47 chromosomes; X-linked dominant Sex: nuclear chromatin pattern female (lethal in male) Associated with: renal polycystic disease mental retardation
hypertelorism
cleft lip + tongue, lingual hamartoma
bifid nasal tip
cleft in palate + jaw bone hypoplasia of mandible (micrognathia) + occiput of skull hypodontia clinodactyly, syndactyly, brachydactyly (metacarpals may be elongated), polysyndactyly, duplication of hallux
P.131
Osgood-Schlatter Disease
[Robert B. Osgood (1873 1956), Boston orthopedic surgeon]
[Carl Schlatter (1864 1934), surgeon in Zurich, Switzerland]
= traumatically induced disruption of the attachment of the patellar ligament to the tibial tuberosity (chronic fatigue injury, NOT osteonecrosis); bilateral in 25%
Age: 10 15 years; M > F Cause: trauma (common in sports that involve jumping, kicking, squatting) =? cartilaginous avulsion fracture,? tendinitis local pain + tenderness on pressure
swelling of overlying soft tissue
soft-tissue swelling in front of tuberosity (= edema of skin + subcutaneous tissue) thickening of distal portion of patellar tendon indistinct margin of patellar tendon increased radiodensity of infrapatellar fat pad avulsion with separation of small ossicles from the developing ossification center of tibial tuberosity single / multiple ossifications in avulsed fragment comparison with other side (irregular development normal) MR:
increased signal intensity at tibial insertion site of patellar tendon on T1WI + T2WI distension of deep infrapatellar bursa bone marrow signal changes in tibial tuberosity + tibial apophysis (rare)
Cx: | nonunion of bone fragment, patellar subluxation, chondromalacia, avulsion of patellar tendon, genu recurvatum |
Rx: | immobilization / steroid injection |
DDx: | (1) Normal ossification pattern of tibial tuberosity between ages 8 14 (no symptoms) |
(2) Osteitis: tuberculous / syphilitic | |
(3) Soft-tissue sarcoma with calcifications |
Ossifying fibroma
Closely related to fibrous dysplasia + adamantinoma
Age: 2nd 4th decade; M < F Histo: maturing cellular fibrous spindle cells with osteoblastic activity producing many calcific cartilaginous + bone densities Location: frequently in face @ Mandible, maxilla
painless expansion of tooth-bearing portion of jaw
1 5 cm well-circumscribed round / oval tumor moderate expansion of intact cortex homogeneous tumor matrix dislodgment of teeth
@ Tibia
eccentric ground-glass lesion (resembling fibrous dysplasia)
Cx: | frequent recurrences |
Osteitis Condensans ILII
Incidence: | 2% of population |
Cause: | chronic stress secondary to instability of pubic symphysis |
Age: | young multiparous women |
associated with low back pain when instability of pubic symphysis present
triangular area of sclerosis along inferior anterior aspect of ileum adjacent to SI joint (joint space uninvolved) similar triangle of reparative bone on sacral side usually bilateral + symmetric; occasionally unilateral sclerosis dissolves in 3 20 years following stabilization of pubic symphysis
DDx: | (1) Ankylosing spondylitis (affects ilium + sacrum, joint space narrowing, involvement of other bones) |
(2) Rheumatoid arthritis (asymmetric, joint destruction) | |
(3) Paget disease (thickened trabecular pattern) |
Osteoarthritis
= DEGENERATIVE JOINT DISEASE
= predominantly noninflammatory degeneration of cartilage in synovial joints
Cause: (1) abnormal forces acting on a normal joint (eg, slipped capital femoral epiphysis) (2) normal forces acting on abnormal joint due to (a) cartilage abnormality (b) subchondral bone abnormality Path: decreased chondroitin sulfate with age creates unsupported collagen fibrils followed by irreversible hyaline cartilage degeneration (= inability for regeneration) Stages:
cartilage swelling + softening from damage to collagen matrix resulting in decreased proteoglycan content and aggregate size + increase in water content
increased cartilage thickness from proliferation of chondrocytes with increase in anabolic + catabolic activity
cartilage loss with continued damage due to decrease in cellular proliferation of chondrocytes resulting in fibrillation + erosion + cracking of articular cartilage
joint space narrowing (stage III) = inaccurate indicator of cartilage integrity subchondral sclerosis / eburnation in areas of stress subchondral cyst formation (geodes) increased joint fluid synovial inflammation (in severe osteoarthritis) osteophytosis at articular margin / nonstressed area MR:
increased signal intensity of abnormal cartilage on T2WI (= increased amount of free water) morphologic defects on surface of cartilage (best seen on fat-suppressed spoiled gradient-echo MR)
@ Hand + foot
Target area: 1st MCP; trapezioscaphoid; DIP > PIP; 1st MTP loss of joint space, subchondral eburnation, marginal osteophytes, small ossicles in DIP + PIP: Bouchard nodes = osteophytosis at PIP joint Heberden nodes = osteophytosis at DIP joint:M:F = 1:10
radial subluxation of 1st metacarpal base joint space narrowing + eburnation of trapezioscaphoid area
@ Shoulder
elevation of humeral head + lack of significant glenohumeral joint involvement (DDx to rheumatoid arthritis)
@ Hip
femoral + acetabular osteophytes, sclerosis, subchondral cyst formation thickening / buttressing of medial femoral cortex / calcar migration of femoral head superolateral subluxation of femoral head medial / axial subluxation protrusio acetabuli (in 20%) primary hereditary protrusio = Otto pelvis (M < F)
@ Knee
Location: medial > lateral femorotibial > patellofemoral compartment varus deformity (M>>F)
@ Spine
sclerosis + narrowing of intervertebral apophyseal joints osteophytosis usually associated with diskogenic disease
@ Sacroiliac joint
Most common disorder of sacroiliac joints Location: bi- / unilateral (contralateral SIJ with bad hip) diffuse joint space loss vacuum phenomenon well-defined line of sclerosis, especially on iliac side of articulation prominent bridging osteophyte at superior + inferior limits of joint
P.132
DDx: | osteoblastic metastasis |
Erosive Osteoarthritis
= inflammatory form of osteoarthrosis
Predisposed: postmenopausal females Site: distribution identical to noninflammatory osteoarthritis: DIP > PIP > MCP joints of hands; radial aspect of wrist; bilateral + symmetric bird-wing / sea-gull joint configuration = central erosions + osteophytosis may lead to bony ankylosis
DDx: | Rheumatoid arthritis, Wilson disease, chronic liver disease, hemochromatosis |
Early Osteoarthritis
mnemonic: | Early OsteoArthritis |
Epiphyseal dysplasia, multiple
Ochronosis
Acromegaly
Milwaukee Shoulder
= association of
complete rotator cuff tear
osteoarthritic changes
noninflammatory joint effusion containing calcium hydroxyapatite and calcium pyrophosphate dihydrate (CPPD) crystals
hyperplasia of synovium
destruction of cartilage + subchondral bone
multiple osteochondral loose bodies
Age: older women
frequent history of trauma
rapidly progressive arthritis of shoulder
Radiograph:
joint space narrowing subchondral sclerosis + cyst formation destruction of subchondral bone soft-tissue swelling capsular calcifications intraarticular loose bodies
MR:
large effusion complete rotator cuff tear narrowing of glenohumeral joint
Rapidly Destructive Articular Disease
= unusual form of osteoarthritis typically involving the hip (almost always unilateral)
Age: elderly women Associated with: conventional osteoarthritis in hands, wrists, knees, opposite hip hip pain
progressive loss of joint space loss of subchondral bone in femoral head + acetabulum resulting in hatchet deformity of femoral head superolateral subluxation of femoral head / intrusion deformity within ilium no / small osteophytes Prognosis: rapid destruction of hip within 14 months after onset of symptoms Rx: total joint replacement DDx: osteonecrosis, septic arthritis, neuroarthropathy, crystal-induced arthropathy
Osteoblastoma
= GIANT OSTEOID OSTEOMA = OSTEOGENIC FIBROMA OF BONE = OSSIFYING FIBROMA
= rare benign tumor with unlimited growth potential + capability of malignant transformation
Incidence: <1% of all primary bone tumors; 3% of all benign bone tumors Age: mean age of 16 19 years; 6 30 years (90%); 2nd decade (55%); 3rd decade (20%); M:F = 2:1 Path: lesion >1.5 cm; smaller lesions are classified as osteoid osteoma Histo: numerous multinucleated giant cells (osteoclasts), irregularly arranged osteoid + bone; very vascular connective tissue stroma with interconnecting trabecular bone; trabeculae broader + longer than in osteoid osteoma asymptomatic in <2%
dull localized pain of insidious onset (84%), worse at night in 7 13%
response to salicylates in 7%
localized swelling, tenderness, decreased range of motion (29%)
painful scoliosis in 50% (with spinal / rib location) secondary to muscle spasm, may be convex toward side of tumor
paresthesias, mild muscle weakness, paraparesis, paraplegia (due to cord compression)
occasional systemic toxicity (high WBC, fever)
Location: (rarely multifocal) spine (33 37%): 62 94% in posterior elements, secondary extension into vertebral body (28 42%); cervical spine (31%), thoracic spine (34%), lumbar spine (31%), sacrum (3%)
long bones (26 32%): femur (50%), tibia (19%), humerus (19%), radius (8%), fibula (4%); unusual in neck of femur
small bones of hand + feet (15 26%): dorsal talus neck (62%), calcaneus (4%), scaphoid (8%), metacarpals (8%), metatarsals (8%)
calvarium + mandible (= cementoblastoma)
Site: diaphyseal (58%), metaphyseal (42%); eccentric (46%), intracortical (42%), centric (12%), may be periosteal
similar to osteoid osteoma: radiolucent nidus >2 cm (range of 2 12 cm) in size well demarcated (83%) stippled / ringlike small flecks of matrix calcification reactive sclerosis (22 91%) / no sclerosis (9 56%)
progressive expansile lesion that may rapidly increase in size (25%): cortical expansion (75 94%) / destruction (20 22%) tumor matrix radiolucent (25 64%) / ossified (36 72%) sharply defined soft-tissue component thin shell of periosteal new bone (58 77%) / no periosteal reaction
scoliosis (35%) osteoporosis due to disuse + hyperemia in talar location rapid calcification after radiotherapy CT:
multifocal matrix mineralization, sclerosis expansile bone remodeling, thin osseous shell
NUC:
intense focal accumulation of bone agent (100%)
Angio:
tumor blush in capillary phase (50%)
MR:
low to intermediate signal intensity on T1WI mixed intermediate to high intensity on T2WI surrounding edema Prognosis: 10% recurrence after excision; incomplete curettage can effect cure due to cartilage production + trapping of host lamellar bone
DDx:
Osteo- / chondrosarcoma (periosteal new bone)
Osteoid osteoma (dense calcification + halo of bone sclerosis, stable lesion size <2 cm due to limited growth potential)
Cartilaginous tumors (lumpy matrix calcification
Giant cell tumor (no calcification, epiphyseal involvement)
Aneurysmal bone cyst
Osteomyelitis
Hemangioma
Lipoma
Epidermoid
Fibrous dysplasia
Metastasis
Ewing sarcoma
P.133
Osteochondroma
= OSTEOCARTILAGINOUS EXOSTOSIS
= developmental hyperplastic / dysplastic bone disturbance composed of cancellous bone surrounded by cortical bone; growth ends when nearest epiphyseal plate fuses
Most common benign growth of the skeleton! Most common benign cartilage-containing tumor! Etiology: separation of a fragment of physeal cartilage herniating through periosteal bone cuff that surrounds the growth plate (encoche of Ranvier); the fragment continues to grow and undergoes enchondral ossification microtrauma / Salter-Harris injury with in vivo transplantation of physeal tissue
radiation therapy (in 6 24%) with latency period of 3 17 years in patients between 8 months and 11 years of age receiving 1,500 5,500 cGy (frequently for treatment of neuroblastoma / Wilms tumor)
Most common benign radiation-induced tumor Path: continuity of lesion with marrow + cortex of host bone (HALLMARK) Histo: hyaline cartilage cap containing a basal surface with enchondral ossification (thin cortex + trabecular bone + marrow space)
continuity of bone cortex with host bone cortex continuity of medullary marrow space with host bone hyaline cartilaginous cap: arcs / rings / flocculent calcifications on radiographs
growth pointing away from nearest joint + toward center of shaft: at right angle on diaphyseal side of stalk slope on epiphyseal side
CT:
optimal depiction of cortical + marrow continuity with host bone (PATHOGNOMONIC) nonmineralized cartilage cap hypodense to muscle (in 75 80%): 6 8 mm thick in skeletally mature patients up to 30 mm thick in skeletally immature patients
MR:
cortical + medullary continuity (MR best modality) hyaline cartilage cap very hyperintense on T2WI + of low to intermediate intensity on T1WI reflecting high water content: hypointense mineralized areas of cartilage hypointense periphery = perichondrium slight septal + peripheral enhancement
US:
hypoechoic nonmineralized cartilaginous cap easily distinguished from muscle and fat posterior acoustic shadowing for mineralized portion
NUC:
active lesion (predominantly in young patient) quiescent lesion in older patient Prognosis: exostosis begins in childhood; stops growing when nearest epiphyseal center fuses Rx: surgical excision (2% recurrence rate, 13% complication rate [neuropraxia, arterial laceration, compartment syndrome, fracture])
Cx:
Osseous and cosmetic deformity (most frequent)
mechanical limitation of joint movement
snapping tendon / ligament
hematuria (irritating pubic osteochondroma)
saucerization / scalloping of cortex of adjacent bone due to extrinsic pressure erosion (of paired tubular bones) premature osteoarthritis pleural effusion / spontaneous hemothorax (due to irritating rib lesion)
Fracture through stalk of osteochondroma
Vascular compromise
venous / arterial stenosis
arterial occlusion / venous thrombosis
pseudoaneurysm formation:
Cause: repetitive trauma to vessel wall Age: near end of normal skeletal growth Location: popliteal a., brachial a., superficial femoral a., posterior tibial a.
Neurologic compromise
peripheral nerve compression with entrapment neuropathy: foot drop with peroneal nerve involvement (most frequent)
central nerve compression: cranial nerve deficit, radiculopathy, cauda equina syndrome, cord compression with myelomalacia
often very narrow stalk of attachment difficult imaging diagnosis owing to complex anatomy of skull base (21% TP) spinal canal osteochondroma (15% FN)
Reactive bursa formation (in 1.5%)
enlarging mass overlying an osteochondroma simulating malignant transformation
Location: scapula (>50%), lesser trochanter, shoulder fluid-filled mass chondral filling defects: mineralization of intrabursal chondral bodies may mimic a thick cartilage cap with growth Cx: inflammation, infection, hemorrhage into bursa, secondary synovial chondromatosis
Malignant transformation into secondary / peripheral chondrosarcoma / osteosarcoma
Frequency: 1% in solitary osteochondroma; 3 5% in hereditary multiple osteochondromatosis Location: iliac bone commonest site Any cartilage cap >1.5 cm thick / continued growth after skeletal maturation is suspect of malignant transformation! mnemonic: GLAD PAST Growth after physeal closure
Lucency (new radiolucency)
Additional scintigraphic activity
Destruction (cortical)
Pain after puberty
And
Soft-tissue mass
Thickened cartilaginous cap >1.5 cm
P.134
Osteochondromatous Variants
Dysplasia epiphysealis hemimelica
Subungual exostosis
Turret exostosis
Traction exostosis (at tendinous attachments)
Bizarre parosteal osteochondromatous proliferation = Nora lesion
Florid reactive periostitis
Solitary Osteochondroma
Frequency: | 1 2%; M:F = 1.6:1 3.4:1 |
20 50% of benign bone tumors; | |
10 15% of all bone tumors | |
Age: | 1st 3rd decade; M:F = 1.5:1 |
incidental nontender painless mass near joints
symptomatic (in 75% before the age of 20 years)
Site: | metaphysis of long bones; rarely diaphysis |
Location: | in any bone that develops by enchondromal calcification; femur (30%), tibia (15 20%), about knee (40%), humerus (10 20%), hands and feet (10%), pelvis (5%), scapula (4%), rib (3%), spine (2%, cervical [esp. C2] > thoracic [T8 > T4] > lumbar) |
Type: | (a) pedunculated osteochondroma = narrow stalk |
(b) sessile osteochondroma = broad base |
Hereditary Multiple Exostoses
= DIAPHYSEAL ACLASIS (ACLASIA) = MULTIPLE OSTEOCHONDROMAS = FAMILIAL OSTEOCHONDROMATOSIS
= most common of osteochondrodysplasias characterized by formation of multiple exostoses
Prevalence: 1:50,000 1:100,000; 1:1,000 on Guam / Mariana Islands Genetics: autosomal dominant (incomplete penetrance in females); 3 distinct loci on chromosomes 8, 11, 19 2/3 of affected individuals have a positive family history Age: forms shortly after birth; virtually all patients discovered by 12 years of age; M:F = 1.5:1.0 short stature (40%) due to development of exostoses at the expense of longitudinal bone growth
Location: multiple + usually bilateral; knee (70 98%), humerus (50 98%), scapula + rib (40%), elbow (35 40%), hip (30 90%), wrist (30 60%), ankle (25 54%), hand (20 30%), foot (10 25%), pelvis (5 15%), vertebra (7%) Site: metaphyses of long bones near epiphyseal plate (distance to epiphyseal line increases with growth) disproportionate shortening of an extremity (50%) @ Upper extremity
pseudo-Madelung deformity: ulnar shortening + longer bowed radius ulnar tilt of distal radial articular surface ulnar deviation of hand
dislocation of radial head radioulnar synostosis shortening of 4th + 5th metacarpals supernumerary fingers / toes
P.135
@ Lower extremity
coxa valga (25%) genu valgus (20 40%) valgus deformity of ankle = tibiotalar tilt (45 54%) undertubulation with widened metadiaphyseal junction: Erlenmeyer flask deformity of distal femur
CT:
wavy pelvis sign = small sessile lesion create undulating cortical contour
Osteochondrosis Dissecans
= Osteochondritis dissecans = Osteochondral Fracture
= fragmentation + possible separation of a portion of the articular surface
Etiology:
subchondral fatigue fracture as a result of shearing, rotatory / tangentially aligned impaction forces / repetitive microtrauma
autosomal dominant trait associated with short stature, endocrine dysfunction, Scheuermann disease, Osgood-Schlatter disease, tibia vara, carpal tunnel syndrome
Age: adolescence; M > F
asymptomatic / vague complaints
clicking, locking, limitation of motion
swelling, pain aggravated by movement
Location:
knee: medial (in 10% lateral) femoral condyle close to fossa intercondylaris; bilateral in 20 30%
humeral head
capitellum of elbow
talus
purely cartilaginous fragment unrecognized on plain film fracture line parallels joint surface mouse = osteochondrotic fragment Location: posterior region of knee joint, olecranon fossa, axillary / subscapular recess of glenohumeral joint mouse bed = sclerosed pit in articular surface soft-tissue swelling, joint effusion MR:
focus of abnormal signal in subarticular marrow defect in overlying cartilage loose bodies of heterogeneous low-signal intensity in coronoid + olecranon fossa outlined by hyperintense joint fluid on T2WI
DDx: | spontaneous osteonecrosis, neuroarthropathy, degenerative joint disease, synovial osteochondromatosis |
Osteochondritis Dissecans of Capitellum
Age: | adolescent boys 13 16 years of age |
Cause: | overhead throwing activity / gymnastics |
dull poorly localized pain in elbow
limited extension + locking of elbow
lucent defect within capitellum flattening of anterior border of capitellum
Osteofibrous Dysplasia
= entity previously mistaken for fibrous dysplasia
Age: newborn up to 5 years Histo: fibrous tissue surrounding trabeculae in a whorled storiform pattern Location: normally confined to tibia (middiaphysis in 50%), lesion begins in anterior cortex; ipsilateral fibula affected in 20% enlargement of tibia with anterior bowing cortex thin / invisible periosteal expansion sclerotic margin (DDx: nonosteogenic fibroma, chondromyxoid fibroma) spontaneous regression in 1/3
Cx: | pathologic fracture in 25%, fractures will heal with immobilization; infrequently complicated by pseudarthrosis |
DDx: | fibrous dysplasia, Paget disease |
Osteogenesis Imperfecta
= PSATHYROSIS = FRAGILITAS OSSIUM = LOBSTEIN DISEASE
= heterogeneous group of a generalized connective tissue disorder leading to micromelic dwarfism characterized by bone fragility, blue sclerae, and dentinogenesis imperfecta
Incidence: overall in 1:28,500 (1:20,000 1:60,000) live births; M:F = 1:1 Histo: immature collagen matrix (due to decreased / defective type I collagen synthesis) Genetics: mutation of COL1A1 gene on chromosome 17 and COL1A2 gene on chromosome 7 soft skull (caput membranaceum)
hyperlaxity of joints
blue sclerae
poor dentition
otosclerosis
thin loose skin
diffuse demineralization, deficient trabecular structure, cortical thinning defective cortical bone: increase in diameter of proximal ends of humeri + femora; slender fragile bone; multiple cystlike areas multiple fractures + pseudarthrosis with bowing (vertebral bodies, long bones) normal / exuberant callus formation rib thinning / notching thin calvarium sinus + mastoid cell enlargement otosclerosis = otospongiosis (= thickened undermineralized otic capsule due to markedly delayed + deficient ossification of all 3 layers) microfractures + deformities of middle ear ossicles (crus of stapes + handle of malleolus) wormian bones persisting into adulthood basilar impression (= platybasia) biconcave vertebral bodies + Schmorl nodes, increased height of intervertebral disk space bowing deformities after child begins to walk
Cx: | (1) Impaired hearing / deafness from otosclerosis (20 60%) |
(2) Death from intracranial hemorrhage (abnormal platelet function) | |
Dx: | chorionic villous sampling |
P.136
Osteogenesis Imperfecta Type I
= OSTEOGENESIS IMPERFECTA TARDA
Most common form of mild-to-moderate disease Transmission: autosomal dominant with varying expression; compatible with life Age at presentation: blue sclerae (50%)
presenile hearing loss (50%)
normal / abnormal dentinogenesis
infants of normal weight + length osteoporosis fractures in neonate (occurring during delivery)
OB-US:
marked bowing of long bones NO IUGR
Osteogenesis Imperfecta Type II
= CONGENITAL LETHAL OSTEOGENESIS IMPERFECTA
= perinatal (obstetrical) lethal form
Transmission: sporadic new dominant mutations / autosomal recessive Incidence: 1:54,000 births; most frequent variety disease manifest at birth (in utero)
blue sclerae
hearing loss
ligamentous laxity + loose skin
shortened broad crumpled long bones bone angulations, bowing, demineralization localized bone thickening from callus formation thin beaded ribs fractures resulting in bell-shaped / narrow chest thin poorly ossified skull wormian bones (present in most cases) spinal osteopenia platyspondyly OB-US:
A normal sonogram after 17 weeks MA excludes the diagnosis! increased through-transmission of skull (extremely poor mineralization): unusually good visualization of brain surface unusually good visualization of orbits increased visualization of intracranial arterial pulsations
abnormal compressibility of skull vault with transducer decreased visualization of skeleton multiple fetal fractures + deformities of long bones + ribs: wrinkled appearance of bone (= more than one fracture in single bone) beaded ribs (callus formation around fractures)
abnormally short limbs small thorax (collapse of thoracic cage) decreased fetal movement infants small for gestational age (frequent) polyhydramnios + nonimmune hydrops
Prognosis: | stillborn / death shortly after birth due to pulmonary hypoplasia |
DDx: | congenital hypophosphatasia; achondrogenesis type I; camptomelic dysplasia |
Osteogenesis Imperfecta Type III
= SEVERE PROGRESSIVELY DEFORMING OI
Transmission: autosomal recessive; progressively deforming disorder compatible with life bluish sclerae during infancy that turn pale with time
joint hyperlaxity (50%)
hearing loss (common)
decreased ossification of skull normal vertebrae + pelvis shortened + bowed long bones progressive deformities of limbs + spine into adulthood rib fractures multiple fractures present at birth in 2/3 of cases fractures heal well OB-US:
short + bowed long bones fractures humerus almost normal in shape normal thoracic circumference
Prognosis: | progressive limb + spine deformities during childhood / adolescence |
Osteogenesis Imperfecta Type IV
Transmission: | autosomal dominant; mildest form with best prognosis |
normal scleral color
little tendency to develop hearing loss
tubular bones of normal length; mild femoral bowing may occur osteoporosis OB-US:
bowing of long bones
Osteoid Osteoma
= benign skeletal neoplasm composed of osteoid + woven bone less than 1.5 cm in diameter per definition
Incidence: 12% of benign skeletal neoplasms Etiology: ? inflammatory response Histo: small nidus of osteoid-laden interconnected trabeculae with a background of highly vascularized fibrous connective tissue surrounded by zone of reactive bone sclerosis; osteoblastic rimming; indistinguishable from osteoblastoma Age: 10 20 years (51%); 2nd + 3rd decade (73%); 5 25 years (90%); range of 19 months 56 years; uncommon <5 and >40 years of age; M:F = 2:1; uncommon in Blacks tender to touch + pressure
local pain (95 98%), weeks to years in duration, worse at night, decreased by activity
salicylates give relief in 20 30 minutes in 75 90%
prostaglandin E2 elevated 100 1000 normal within nidus (probable cause of pain and vasodilatation)
Location:
meta- / diaphysis of long bones (73%): upper end of femur (43%), hands (8%), feet (4%); frequent in proximal tibia + femoral neck, fibula, humerus; no bone exempt
spine (10 14%): predominantly in posterior elements (50% in pedicle + lamina + spinous process; 20% in articular process) of lumbar (59%), cervical (27%), thoracic (12%), sacral (2%) segments
painful scoliosis, focal / radicular pain gait disturbance, muscle atrophy
skull, rib, ischium, mandible, patella
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round / oval radiolucent nidus (75%) of <1.5 cm in size variable surrounding sclerosis central calcification painful scoliosis concave toward lesion / kyphoscoliosis / hyperlordosis / torticollis with spinal location (due to spasm) may show extensive synovitis + effusion + premature loss of cartilage with intraarticular site (lymphofollicular synovitis) osteoarthritis (50%) with intraarticular site 1.5 22 years after onset of symptomatology regional osteoporosis (probably due to disuse) Radiographically difficult areas: vertebral column, femoral neck, small bones of hand + feet NUC:
intensely increased radiotracer uptake (increased blood flow + new-bone formation) double density sign = small area of focal activity (nidus) superimposed on larger area of increased tracer uptake
CT (for detection + precise localization of nidus):
small well-defined round / oval nidus surrounded by variable amount of sclerosis nidus enhances on dynamic scan nidus with variable amount of mineralization (50%): punctate / amorphous / ringlike / dense
MR (diminished conspicuity of lesion compared with CT):
nidus isointense to muscle on T1WI signal intensity increases to between that of muscle + fat / remains low on T2WI perinidal inflammation of bone marrow (63%) perinidal soft-tissue inflammation / edema (47%) synovitis + joint effusion with intraarticular site
Angio:
highly vascularized nidus with intense circumscribed blush appearing in early arterial phase + persisting late into venous phase Prognosis: no growth progression, infrequent regression Rx: (1) complete surgical excision of nidus (reactive bone regresses subsequently) (2) percutaneous CT-guided removal (3) percutaneous ablation with radio-frequency electrode / laser / alcohol DDx: (1) Cortical osteoid osteoma: Brodie abscess, sclerosing osteomyelitis, syphilis, bone island, stress fracture, osteosarcoma, Ewing sarcoma, osteoblastic metastasis, lymphoma, subperiosteal aneurysmal bone cyst, osteoblastoma (progressive growth) (2) Intraarticular osteoid osteoma: inflammatory / septic / tuberculous / rheumatoid arthritis, nonspecific synovitis / legg-Calv -Perthes disease
Cortical osteoid osteoma (most common)
= nidus within cortex
solid / laminated periosteal reaction fusiform sclerotic cortical thickening in shaft of long bone radiolucent area within center of osteosclerosis
Cancellous Osteoid Osteoma (intermediate frequency)
= intramedullary
Intraarticular lesion difficult to identify with delay in diagnosis of 4 months 5 years! Site: juxta- / intraarticular at femoral neck, vertebral posterior elements, small bones of hands + feet little osteosclerosis / sclerotic cortex distant to nidus (functional difference of intraarticular periosteum) joint space widened (effusion, synovitis)
Subperiosteal Osteoid Osteoma (rare)
= round soft-tissue mass adjacent to bone
Site: juxta- / intraarticular at medial aspect of femoral neck, hands, feet (neck of talus) juxtacortical mass excavating the cortex (bony pressure atrophy) with almost no reactive sclerosis
Osteoma
= benign tumor of membranous bone (hamartoma)
Age: adult life Associated with: Gardner syndrome (multiple osteomas + colonic polyposis) Location: inner / outer table of calvarium (usually from external table), paranasal sinuses (frontal / ethmoid sinuses), mandible, nasal bones well-circumscribed round extremely dense structureless lesion usually <2 cm in size
Fibrous Osteoma
Probably a form of fibrous dysplasia
Age: childhood less dense than osteoma / radiolucent expanding external table without affecting internal table DDx: endostoma, bone island, bone infarct (located in medulla)
Osteomyelitis
= infection of bone caused by bacteria, fungi, parasites, viruses
Acute Osteomyelitis
Age: | most commonly affects children |
Organism:
newborns: S. aureus, group B streptococcus, Escherichia coli
children: S. aureus (blood cultures in 50% positive)
adults: S. aureus (60%), enteric species (29%), Streptococcus (8%)
drug addicts: Pseudomonas (86%), Klebsiella, Enterobacteriae; (57 days average delay in diagnosis)
sickle cell disease: S. aureus, Salmonella
diabetics: often multiple organisms like S. aureus, Streptococcus, E. coli, Klebsiella, Clostridia, Pseudomonas (in soil + sole of shoes)
Cause:
genitourinary tract infection (72%)
lung infection (14%)
dermal infection (14%): direct contamination from a soft-tissue lesion in diabetic patient
Pathogenesis:
hematogenous spread
direct implantation from a traumatic / iatrogenic source
extension from adjacent soft-tissue infection
Location:
@ Lower extremity (75%) over pressure points in diabetic foot
@ Vertebrae (53%)
lumbar (75%) > thoracic > cervical (= infectious spondylitis)
@ Radial styloid (24%)
@ Sacroiliac joint (18%)
leukocytosis + fever (66%)
Conventional radiographs (insensitive):
initial radiographs often normal (notoriously poor in early phase of infection for as long as 10 14 days) localized soft-tissue swelling adjacent to metaphysis with obliteration of usual fat planes (after 3 10 days) permeative metaphyseal osteolysis (lags 7 14 days behind pathologic changes) endosteal erosion intracortical fissuring involucrum = cloak of laminated / spiculated periosteal reaction (develops after 20 days) button sequestrum = detached necrotic cortical bone (develops after 30 days) cloaca formation = space in which dead bone resides
CT:
marrow density of >+20 HU difference to healthy side indicates marrow infection
MR (82% sensitive, 80% specific in diabetics):
bone marrow hypointense on T1WI + hyperintense relative to normal fatty marrow on T2WI / STIR (= water-rich inflammatory tissue + edema fluid) bone marrow edema in bones adjacent to an infected point does not reliably indicate osteomyelitis periarticular bone marrow edema can be seen adjacent to joints involved by noninfectious inflammatory arthropathy / osteoarthritis
variable enhancement after IV administration of Gd-chelate focal / linear cortical involvement hyperintense on T2WI hyperintense halo surrounding cortex on T2WI = subperiosteal infection hyperintense line on T2WI extending from bone to skin surface + enhancement of borders (= sinus tract) cortical disruption, sequestrum Abscess characteristics:
hyperintense enhancing rim (= hyperemic zone) around a central focus of low intensity (= necrotic / devitalized tissue) on contrast-enhanced T1WI hyperintense fluid collection surrounded by hypointense pseudocapsule on T2WI + contrast enhancement of granulation tissue hyperintense adjacent soft tissues on T2WI fat-suppressed contrast-enhanced imaging (88% sensitive + 93% specific compared with 79% + 53% for nonenhanced MR imaging)
NUC (accuracy approx. 90%):
Ga-67 scans: 100% sensitivity; increased uptake 1 day earlier than for Tc-99m MDP
Gallium helpful for chronic osteomyelitis!
Static Tc-99m diphosphonate: 83% sensitivity 5 60% false-negative rate in neonates + children because of
masking effect of epiphyseal plates
early diminished blood flow with infection
spectrum of uptake pattern from hot to cold
Three-phase skeletal scintigraphy:
92% sensitivity, 87% specificity
Phase 1: Radionuclide angiography = perfusion phase of regional blood flow Phase 2: blood pool images Phase 3: bone uptake Limitations: diagnostic difficulties in children, in posttraumatic / postoperative state, diabetic neuropathy (poor blood supply), neoplasia, septic arthritis, Paget disease, healed osteomyelitis, noninfectious inflammatory process DDx: cellulitis (decrease in activity over time)
WBC-scan:
In-111 labeled leukocytes: best agent for acute infections
Tc-99m labeled leukocytes: preferred over In-111 leukocyte imaging especially in extremities
WBC scans have largely replaced gallium imaging for acute osteomyelitis due to improved photon flux + improved dosimetry (higher dose allowed relative to In-111) allowing faster imaging + greater resolution
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cold area in early osteomyelitis subsequently becoming hot if localized to long bones / pelvis (not seen in vertebral bodies) local increase in radiopharmaceutical uptake (positive within 24 72 hours)
Cx: | (1) Soft-tissue abscess |
(2) Fistula formation | |
(3) Pathologic fracture | |
(4) Extension into joint | |
(5) Growth disturbance due to epiphyseal involvement | |
(6) Neoplasm | |
(7) Amyloidosis | |
(8) Severe deformity with delayed treatment |
Acute Neonatal Osteomyelitis
Age: | onset <30 days of age |
little / no systemic disturbance
multicentric involvement more common; often joint involvement bone scan falsely negative / equivocal in 70%
Acute Osteomyelitis in Infancy
Age: | <18 months of age |
Pathomechanism: | spread to epiphysis because transphyseal vessels cross growth plate into epiphysis |
striking soft-tissue component subperiosteal abscess with extensive periosteal new bone
Cx: | frequent joint involvement |
Prognosis: | rapid healing |
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Acute Osteomyelitis in Childhood
Age: | 2 16 years of age |
Pathomechanism:
transphyseal vessels closed; metaphyseal vessels adjacent to growth plate loop back toward metaphysis locating the primary focus of infection into metaphysis; abscess formation in medulla with cortical spread
Location: femur, tibia
sequestration frequent periosteal elevation (with disruption of periosteal blood supply) small single / multiple osteolytic areas in metaphysis extensive periosteal reaction parallel to shaft (after 3 6 weeks); may be lamellar nodular (DDx: osteoblastoma, eosinophilic granuloma) shortening of bone with destruction of epiphyseal cartilage growth stimulation by hyperemia + premature maturation of adjacent epiphysis midshaft osteomyelitis less frequent site serpiginous tract with small sclerotic rim (PATHOGNOMONIC)
Acute Osteomyelitis in Adulthood
Associated with: | soft-tissue abscess, pathological fracture |
Risk factors: | IV drug use, previous trauma, immunosuppressed state, diabetes |
delicate periosteal new bone joint involvement common
Diabetic foot
Cause: | callus / minor skin trauma (eg, toenail cutting) |
Pathophysiology: | pressure points callus ulceration osteomyelitis |
Location:
@ typical sites: heads of 1st + 5th metatarsal bones, calcaneus, malleoli
@ additional sites due to neuropathic foot deformities: cuboid, midfoot (from arch collapse), dorsum of toes
poor healing due to vascular disease
MR:
primary osseous signs:
low marrow signal on T1WI + high on T2WI cortical interruption marrow enhancement periostitis = linear edema / enhancement along outer cortical margin
secondary (soft-tissue) signs (in >90%):
ulcer = interruption of cutaneous signal cellulitis enhancing focal soft-tissue mass effect with edema (= phlegmon) focal fluid signal with rim enhancement = abscess thin linear soft-tissue signal with enhancing margins (high on T2WI) = sinus tract
Cx:
Devitalized tissue = gangrene without infection
focal often triangular nonenhancing area of variable signal intensit central tissue usually of high signal intensity on T2WI signal voids of air enhancing marginal zone
Bone infarct
sharply demarcated nonenhancing marrow
Spread of infection to foot compartments, tendon, joint (= septic arthritis), bone (= osteomyelitis)
DDx: | Neuropathic osteoarthropathy (dislocation, disorganizaton, debris, destruction, density preserved; mildly symptomatic, joint effusion, multiple joints involved, marrow edema, periarticular enhancement; more common in ankle / Lisfranc / Chopart joints) |
Chronic Osteomyelitis
thick irregular sclerotic bone with radiolucencies, elevated periosteum, chronic draining sinus
Sclerosing Osteomyelitis of Garr
= STERILE OSTEOMYELITIS
= low-grade nonnecrotic nonpurulent infection
Location: mandible (most commonly) focal bulge of thickened cortex (sclerosing periosteal reaction) DDx: osteoid osteoma, stress fracture
Chronic Recurrent Multifocal Osteomyelitis
= benign self-limited disease of unknown etiology
Age: children + adolescents; M:F = 1:2 Histo: nonspecific subacute / chronic osteomyelitis pain, soft-tissue swelling, limited motion
Location: tibia > femur > clavicle > fibula Site: metaphyses of long bones; often symmetric small areas of bone lysis, often confluent
Brodie Abscess
= subacute pyogenic osteomyelitis (smoldering indolent infection)
Organism: S. aureus (most common); cultures often negative Histo: granulation tissue + eburnation Age: more common in children; M > F Location: predilection for ends of tubular bones (proximal / distal tibial metaphysis most common); carpal + tarsal bones Site: metaphysis, rarely traversing the open growth plate; epiphysis (in children + infants) lytic lesion often in an oval configuration that is oriented along the long axis of the bone surrounded by thick dense rim of reactive sclerosis that fades imperceptibly into surrounding bone lucent tortuous channel extending toward growth plate prior to physeal closure (PATHOGNOMONIC) periosteal new-bone formation adjacent soft-tissue swelling may persist for many months MR:
double line effect = high signal intensity of granulation tissue surrounded by low signal intensity of bone sclerosis on T2WI well-defined lesion of low- to intermediate signal intensity outlined by low-signal rim on T1WI generally surrounded by marrow edema no / rim enhancement after IV Gd-chelate
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DDx: | Osteoid osteoma |
Epidermoid Carcinoma
Etiology: | complication of chronic osteomyelitis (0.2 1.7%) |
Histo: | squamous cell carcinoma (90%); occasionally: basal cell carcinoma, adenocarcinoma, fibro-sarcoma, angiosarcoma, reticulum cell sarcoma, spindle cell sarcoma, rhabdomyosarcoma, parosteal osteosarcoma, plasmacytoma |
Age: | 30 80 (mean 55) years; M >> F |
Latent period: | 20 30 (range of 1.5 72) years |
history of childhood osteomyelitis
exacerbation of symptoms with increasing pain, enlarging mass
change in character / amount of sinus drainage
Location: at site of chronically / intermittently draining sinus; tibia (50%), femur (21%) lytic lesion superimposed on changes of chronic osteomyelitis soft-tissue mass pathologic fracture Prognosis:
Early metastases in 14 20 40% (within 18 months)
No recurrence in 80%
Osteopathia Striata
= VOORHOEVE DISEASE
= autosomal dominant / sporadic inherited disorder
usually asymptomatic (similar to osteopoikilosis)
Location: all long bones affected; the only bone sclerosis primarily involving metaphysis (with extension into epi- and diaphysis) longitudinal striations of dense bone in metaphysis radiating densities of sunburst appearance from acetabulum into ileum
Osteopetrosis
= ALBERS-SCH NBERG DISEASE = MARBLE BONE DISEASE
= rare hereditary disorder
Path: | defective osteoclast function with failure of proper reabsorption + remodeling of primary spongiosa; bone sclerotic + thick but structurally weak + brittle |
Cx: | (1) Usually transverse fractures (common because of brittle bones) with abundant callus + normal healing |
(2) Crowding of marrow (myelophthisic anemia + extramedullary hematopoiesis) | |
(3) Frequently terminates in acute leukemia | |
Rx: | bone marrow transplant |
DDx: | (1) Heavy metal poisoning |
(2) Melorheostosis (limited to one extremity) | |
(3) Hypervitaminosis D | |
(4) Pyknodysostosis | |
(5) Fibrous dysplasia of skull / face |
Infantile Autosomal Recessive Osteopetrosis
= congenital more severe form
Cause: defect on chromosome 11q13 failure to thrive
premature senile appearance of facies
severe dental caries
pancytopenia (= anemia, leukocytopenia, thrombocytopenia) due to severe marrow depression
cranial nerve compression (optic atrophy, deafness)
hepatosplenomegaly (extramedullary hematopoiesis)
lymphadenopathy
subarachnoid hemorrhage (due to thrombocytopenia)
May be associated with: renal tubular acidosis + cerebral calcification dense skeleton splayed metaphyses + costochondral junctions fractures from minor trauma (due to brittle bones) Prognosis: stillbirth, survival beyond middle life uncommon (death due to recurrent infection, massive hemorrhage, terminal leukemia) DDx: chronic renal failure, oxalosis, pyknodysostosis, physiologic sclerosis
Benign Adult Autosomal Dominant Osteopetrosis
Cause: | defect on chromosome 1p21 |
50% asymptomatic
recurrent fractures, mild anemia
occasionally cranial nerve palsy
Erlenmeyer flask deformity = clublike long bones due to lack of tubulization + flaring of ends Phenotype I:
diffuse osteosclerosis = generalized dense amorphous structureless bones with obliteration of normal trabecular pattern; mandible least commonly involved cortical thickening with medullary encroachment
Phenotype II:
bone-within-bone appearance (= endobones) sandwich vertebrae / rugger-jersey spine alternating sclerotic + radiolucent transverse metaphyseal lines (phalanges, ilium) as indicators of fluctuating course of disease longitudinal metaphyseal striations obliteration of mastoid cells, paranasal sinuses, basal foramina by osteosclerosis sclerosis predominantly involving base of skull; calvaria often spared
Prognosis: | normal life expectancy |
Osteopoikilosis
= OSTEOPATHIA CONDENSANS DISSEMINATA
= rare sclerosing bone dysplasia with autosomal dominant inheritance pattern
Age: no age predilection; M = F Histo: compact bone islands (= cortical bone) Associated with:
@ Dermatologic disorders:
Dermatofibrosis lenticularis disseminata (Buschke-Ollendorf syndrome) = small flesh-colored papules on trunk + extremities (in 25%)
Scleroderma
Keloid formation
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@ Bone abnormalities:
Melorheostosis
Osteopathia striata
commonly asymptomatic
Location: metaphyses + epiphyses (rarely extending into midshaft) of long tubular bones; concentrated at glenoid + acetabulum, carpal + tarsal bones, ankle, pelvis, scapula; rare in skull, ribs, vertebral centra, mandible multiple ovoid / lenticular bone islands (2 10 mm) in cancellous bone in symmetric distribution long axis of lesions parallel to long axis of bone bone scintigraphic activity rare MR signal characteristics equal to cortical bone
Prognosis: | not progressive, no change after cessation of growth |
DDx: | (1) Epiphyseal dysplasia (metaphyses normal) |
(2) Melorheostosis (diaphyseal involvement) | |
(3) Mastocytosis | |
(4) Tuberous sclerosis | |
(5) Osteoblastic metastases |
Osteosarcoma
Most common malignant primary bone tumor in young adults + children; 2nd most common primary malignant bone tumor after multiple myeloma
Prevalence: 4 5:1,000,000; 15% of all primary bone tumors confirmed at biopsy Types & Frequency:
Conventional osteosarcoma:
high-grade intramedullary 75%
telangiectatic 4.5 11%
low-grade intraosseous 4 5%
small cell 1 4%
osteosarcomatosis 3 4%
gnathic 6 9%
Surface / juxtacortical osteosarcoma: 4 10%
intracortical rare
parosteal 65%
periosteal 25%
high-grade surface 10%
Extraskeletal 4%
Secondary osteosarcoma 5 7%
Work-up: local staging by MR before biopsy; distant staging with bone scan + chest CT Prognosis: dependent on age, sex, tumor size, site, classification; best predictor is degree of tissue necrosis in postresection specimen following chemotherapy (91% survival with tumor necrosis >90%, 14% survival with <90% tumor necrosis)
Extraskeletal Osteosarcoma
= located within soft tissue without attachment to bone / periosteum
Incidence: 1.2% of soft-tissue sarcomas Histo: variable amounts of neoplastic osteoid + bone + cartilage; frequently associated with fibrosarcoma, malignant fibrous histiocytoma, malignant peripheral nerve sheath tumor Mean age: 50 years; 94% >30 years of age; M > F Location: lower extremity (thigh in 42 47%), upper extremity (12 23%), retroperitoneum (8 17%), buttock, back, orbit, submental, axilla, abdomen, neck, kidney, breast slowly growing firm soft-tissue mass
painful + tender (25 50%)
history of trauma (12 31%): in preexisting myositis ossificans / site of intramuscular injection
elevated levels of alkaline phosphatase (prognostic)
often deep-seated + fixed soft-tissue tumor (average diameter of 9 cm) focal / massive area of mineralization (>50%) faint moderate inhomogeneous enhancement increased radionuclide uptake on bone scan Prognosis:
multiple local recurrences (in 80 90%) after interval of 2 months to 10 years
metastases after interval of 1 month to 4 years: lungs (81 100%), lymph nodes (25%), bone, subcutis, liver
death within 2 3 years (>50%) with tumor size as major predictor
High-grade Intramedullary Osteosarcoma
= CENTRAL OSTEOSARCOMA = CONVENTIONAL OSTEOSARCOMA
Histo: arising from undifferentiated mesenchymal tissue; forming fibrous / cartilaginous / osseous matrix (mostly mixed) that produces osteoid / immature bone (a) osteoblastic (50 80%) (b) chondroblastic (5 25%) (c) fibroblastic-fibrohistiocytic (7 25%) Age: bimodal distribution 10 25 years and >60 years; 21% <10 years; 68% <15 years; 70% between 10 and 30 years; M:F = 3:2 to 2:1; >35 years: related to preexisting condition painful swelling (1 2 months' duration)
fever (frequent)
slight elevation of alkaline phosphatase
diabetes mellitus (paraneoplastic syndrome) in 25%
Location: long bones (70 80%), femur (40 45%), tibia (16 20%); 50 55% about knee; proximal humerus (10 15%); facial bones (8%); cylindrical bone <30 years; flat bone (ilium) >50 years Site: origin in metaphysis (90 95%) / diaphysis (2 11%) /epiphysis (<1%); growth through open physis with extension into epiphysis (75 88%) Doubling time: 20 30 day usually large bone lesion of >5 6 cm when first detected cloudlike density (90%) / almost normal density / osteolytic (fibroblastic type) aggressive periosteal reaction: sunburst / hair-on-end / onion-peel = laminated / Codman triangle moth-eaten bone destruction + cortical disruption soft-tissue mass with tumor new bone (osseous / cartilaginous type) transphyseal spread before plate closure (75 88%); physis does NOT act as a barrier to tumor spread spontaneous pneumothorax (due to subpleural metastases) NUC (bone scintigraphy):
intensely increased activity on blood flow, blood pool, delayed images (hypervascularity, new-bone formation) soft-tissue extension demonstrated, especially with SPECT bone scan establishes local extent (extent of involvement easily overestimated due to intensity of uptake), skip lesions, metastases to bone + soft tissues
CT:
soft-tissue attenuation (nonmineralized portion) replacing fatty bone marrow low attenuation (higher water content of chondroblastic component / hemorrhage / necrosis) very high attenuation (mineralized matrix)
MR (preferred modality):
tumor of intermediate signal intensity on T1WI + high signal intensity on T2WI clearly defines marrow extent (best on T1WI), vascular involvement, soft-tissue component (best on T2WI)
Evaluate for:
extent of marrow + soft-tissue involvement
invasion of epiphysis
joint (19 24%) + neurovascular involvement
viable tumor + mineralized matrix for biopsy
Metastases (in 2% at presentation):
hematogenous lung metastases (15%): calcifying; spontaneous pneumothorax secondary to subpleural cavitating nodules rupturing into pleural space
lymph nodes, liver, brain (may be calcified)
skeletal metastases uncommon (unlike Ewing sarcoma); skip lesions = discontinuous tumor foci in marrow cavity in 1 25%
Cx: (1) pathologic fracture (15 20%) (2) radiation-induced osteosarcoma (30 years delay) Rx: chemotherapy followed by wide surgical resection Prognosis: 60 80% 5-year survival
amputation: 20% 5-year survival; 15% develop skeletal metastases; 75% dead within <2 years
multidrug chemotherapy: 55% 4-year survival more proximal lesions carry higher mortality (0% 2-year survival for axial primary)
Predictors of poor outcome:
metastasis at presentation, soft-tissue mass >20 cm, pathologic fracture, skip lesions in marrow
Predictors of poor response to chemotherapy:
no change / increase in size of soft-tissue mass, increase in bone destruction
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DDx: | Osteoid osteoma, sclerosing osteomyelitis, Charcot joint |
High-grade Surface Osteosarcoma
Location: | femur, humerus, fibula |
Site: | diaphysis |
similar to periosteal osteosarcoma often involves entire circumference of bone frequent invasion of medullary canal
Prognosis: | identical to conventional intramedullary osteosarcoma |
Intracortical Osteosarcoma
Rarest form of osteosarcoma
Histo: sclerosing variant of osteosarcoma which may contain small foci of chondro- or fibrosarcoma Location: femur, tibia tumor <4 cm in diameter intracortical geographic bone lysis tumor margin may be well defined with thickening of surrounding cortex metastases in 29%
Low-grade Intraosseous Osteosarcoma
= WELL-DIFFERENTIATED / SCLEROSING OSTEOSARCOMA
Path: penetration among bony trabeculae; fibrous stroma sometimes lacking nuclear atypia + pleomorphism; highly variable amount of tumor osteoid production; may be misinterpreted as fibrous dysplasia Age: most frequently 3rd decade; M:F = 1:1 protracted clinical course with nonspecific symptoms
Location: about the knee; femur involved in 50% Site: metaphysis; often with extension into epiphysis may have well-defined margins + sclerotic rim diffuse sclerosis expansile remodeling of bone subtle signs of aggressiveness: bone lysis, focally indistinct margin, cortical destruction, soft-tissue mass, periosteal reaction
N.B.: | the relatively benign appearance has resulted in misdiagnosis as a benign entity! |
Cx: | transformation into high-grade osteosarcoma |
Prognosis: | similar to parosteal osteosarcoma; 80 90% 5-year survival rate; local recurrence in 10% (due to inadequate resection) |
DDx: | fibrous dysplasia, nonossifying fibroma, chondrosarcoma, chondromyxoid fibroma |
Osteosarcoma of Jaw
= GNATHIC OSTEOSARCOMA
Average age: 34 years (10 15 years older than in conventional osteosarcoma) Histo: chondroblastic predominance (~50%), osteoblastic predominance (~25%); better differentiated (grade 2 or 3) than conventional osteosarcoma (grade 3 or 4) simulating periodontal disease: rapidly enlarging mass, lump, swelling
paresthesia (if inferior alveolar nerve involved)
painful / loose teeth, bleeding gum
Location: body of mandible (lytic), alveolar ridge of maxilla (sclerotic), maxillary antrum osteolytic / osteoblastic / mixed pattern osteoid matrix (60 80%) aggressive periosteal reaction for mandibular lesion soft-tissue mass (100%) opacification of maxillary sinus (frequent in maxillary lesions)
Prognosis: | 40% 5-year survival rate (lower probability of metastases, lower grade) |
DDx: | metastatic disease (lung, breast, kidney), multiple myeloma, direct invasion by contiguous tumor from oral cavity, Ewing sarcoma, primary lymphoma of bone, chondrosarcoma, fibrosarcoma, acute osteomyelitis, amelo-blastoma, Langerhans cell histiocytosis, giant cell reparative granuloma, brown tumor of HPT |
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Osteosarcomatosis
= MULTIFOCAL OSTEOSARCOMA = MULTIPLE SCLEROTIC OSTEOSARCOMA
Frequency: 2.7 4.2% of osteosarcomas Etiology:
multicentric type of osteosarcoma
multiple metastatic bone lesions
Classification (Amstutz):
Type I multiple synchronous bone lesions occurring within 5 months of diagnosis + patient 18 years of age Type II multiple synchronous bone lesions occurring within 5 months of presentation + patient >18 years of age Type IIIa early metachronous metastatic osteosarcoma occurring 5 to 24 months after diagnosis Type IIIb late metachronous metastatic osteosarcoma occurring >24 months after diagnosis Age: Amstutz type I = 4 18 (mean 11) years Amstutz type II = 19 63 (mean 30) years Site: metaphysis of long bones; may extend into epiphyseal plate / begin in epiphysis multicentric simultaneously appearing lesions with a radiologically dominant tumor (97%) smaller lesions are densely opaque (osteoblastic) lesions bilateral + symmetrical early: bone islands late: entire metaphysis fills with sclerotic lesions breaking through cortex lesions are of same size lung metastases (62%)
Prognosis: | uniformly poor with mean survival of 12 (range, 6 37) months |
DDx: | heavy metal poisoning, sclerosing osteitis, progressive diaphyseal dysplasia, melorheostosis, osteopoikilosis, bone infarction, osteopetrosis |
Parosteal Osteosarcoma
Frequency: | 4% of all osteosarcomas; 65% of all juxtacortical osteosarcomas |
Origin: | outer layer of periosteum; slowly growing lesion with fulminating course if tumor reaches medullary canal |
Histo: | low-grade lesion with higher-grade regions (22 64%), invasion of medullary canal (8 59%); fibrous stroma + extensive osteoid with small foci of cartilage |
Age: | peak age 38 years (range of 12 58 years); 50% > age 30 (for central osteosarcoma 75% < age 30); M:F = 2:3 |
Location: | posterior aspect of distal femur (50 65%), either end of tibia, proximal humerus, fibula, rare in other long bones |
Site: | metaphysis (80 90%) |
palpable mass
large lobulated cauliflower-like homogeneous ossific mass extending away from cortex string sign = initially fine radiolucent line separating tumor mass from cortex (30 40%) tumor stalk (= attachment to cortex) grows with tumor obliterating the radiolucent cleavage plane cortical thickening without aggressive periosteal reaction tumor periphery less dense than center (DDx: myositis ossificans with periphery more dense than center + without attachment to cortex) large soft-tissue component with osseous + cartilaginous elements
Prognosis: | 80 90% 5- and 10-year survival rates (best prognosis of all osteosarcomas) |
DDx: | osteochondroma, myositis ossificans, juxtacortical hematoma, extraosseous osteosarcoma |
Periosteal Osteosarcoma
Origin: | deep layer of periosteum |
Histo: | intermediate-grade lesion; highly chondroblastic lesion with smaller areas of osteoid formation |
Age: | average 20 years (range of 13 70 years); M:F = 1.7:1 |
Location: | tibia (40%), femur (38%), ulna and humerus (5 10%) |
Site: | anteromedial diaphysis of proximal tibia + middle / distal femur; limited to periphery of cortex with normal endosteal margin + medullary canal (resembles parosteal sarcoma) |
broad-based soft-tissue mass attached to cortex over entire extent of tumor (100%): tumor 7 12 cm in length, 2 4 cm in width involving 50 55% of osseous circumference
cortical thickening (82%): solid nonaggressive (51%) extrinsic scalloping of cortex (92%): affecting only thickened cortex (68%) involving native cortex (32%)
periosteal reaction (95%): short spicules of new bone perpendicular to shaft extending into soft-tissue mass (51%) aggressive periosteal reaction of laminated appearance / Codman triangle (11%) both patterns (38%)
NO cortical destruction / medullary cavity invasion: marrow signal abnormality on MR usually due to reactive changes unless continuous with surface component (2%)
additional areas of matrix calcification by CT (91%) chondroblastic areas (80%) with inherent high water content of hyaline cartilage: hypodense on CT compared to muscle (91%) very high signal intensity on T2WI (83%) Biopsy may lead to erroneous diagnosis of chondrosarcoma!
NM (bone scintigraphy):
eccentric uptake (100%) Prognosis: 80 90% cure rate (better prognosis than central osteosarcoma with 50% 5-year survival but worse than parosteal osteosarcoma)
DDx:
Juxtacortical chondrosarcoma (4 5th decade, extensive osteoid + chondroid mineralization, no perpendicular periosteal reaction)
Ewing sarcoma (rarely periosteal, no perpendicular periosteal reaction, soft-tissue component not mineralized + not low in attenuation + not of very high intensity)
Parosteal osteosarcoma (3rd + 4th decade, posterior distal metaphysis of femur, attached to bone by narrow stalk, no perpendicular periosteal reaction)
High-grade surface osteosarcoma (surrounds >50% of bone circumference, frequent invasion of medullary cavity, no high water content of soft-tissue mass)
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Secondary Osteosarcoma
Most osteosarcomas in patients >60 years of age are secondary! Cause: malignant transformation within benign process Paget disease (67 90%)
0.2 7.5% of patients with Paget disease develop osteosarcoma dependent on extent of disease
Sequelae of irradiation (6 22%) 2 40 years ago (malignant fibrous histiocytoma most common; fibrosarcoma 3rd most common)
0.02 4% of patients with radiation therapy develop osteosarcoma related to exposure dose (usually >1,000 cGy)
Osteonecrosis, fibrous dysplasia, metallic implants, osteogenesis imperfecta, chronic osteomyelitis, retinoblastoma (familial bilateral type)
Path: high-grade anaplastic tissue with little / no mineralization Age: middle-aged / late adulthood
aggressive bone destruction in area of preexisting condition associated with large soft-tissue mass
Prognosis: | <5% 5-year survival rate |
Small-cell Osteosarcoma
Age: | similar to conventional osteosarcoma; M:F = 1:1 |
Histo: | small round blue cells (similar to Ewing sarcoma) lacking cellular uniformity and consistently producing fine reticular osteoid |
Location: | distal femur |
Site: | metaphysis with frequent extension into epiphysis; diaphysis (in 15%) |
predominantly permeative lytic medullary lesion cortical breakthrough aggressive periosteal reaction associated soft-tissue mass
Prognosis: | extremely poor |
Telangiectatic Osteosarcoma
= MALIGNANT BONE ANEURYSM
Frequency: 4 11% of all osteosarcomas Age: 3 67 (mean 20) years; M:F = 3:2 Path: malignant osteoid-forming sarcoma of bone with large blood-filled vascular channels Histo: hemorrhagic + cystic + necrotic spaces occupying >90% of the lesion before therapy; blood-filled cavernous vessels lined with osteoclastic giant cells Location: about knee (62%); distal femur (48%), proximal tibia (14%), proximal humerus (16%) Site: metaphysis (90%); extension into epiphysis (87%) geographic bone destruction with a wide zone of transition marked aneurysmal expansion of bone (19%) fluid-fluid levels (90%) nodular calcific foci of osteoid (61 81%) doughnut sign = peripherally increased uptake with central photopenia on bone scan
DDx: | aneurysmal bone cyst (no enhancing rim of viable tumor along lesion periphery) |
Oxalosis
Rare inborn error of metabolism
Etiology: excessive amounts of oxalic acid combine with calcium and deposit throughout body (kidneys, soft tissue, bone) hyperoxaluria = urinary excretion of oxalic acid >50 mg/ day progressive renal failure
osteoporosis = cystic rarefaction + sclerotic margins in tubular bones on metaphyseal side, may extend throughout diaphysis erosions on concave side of metaphysis near epiphysis (DDx: hyperparathyroidism) bone-within-bone appearance of spine nephrocalcinosis (2 HPT: subperiosteal resorption, rugger jersey spine, sclerotic metaphyseal bands)
Cx: | pathologic fractures |
Pachydermoperiostosis
= OSTEODERMOPATHIA HYPERTROPHICANS (TOURAINE-SOLENTE-GOLE) = PRIMARY HYPERTROPHIC OSTEOARTHROPATHY
Autosomal dominant
Age: 3 38 years with progression into late 20s / 30s; M >> F large skin folds of face + scalp
Location: epiphyses + diametaphyseal region of tubular bones; distal third of bones of legs + forearms (early); distal phalanges rarely involved enlargement of paranasal sinuses irregular periosteal proliferation of phalanges + distal long bones (hand + feet) beginning in epiphyseal region at tendon / ligament insertions thick cortex, BUT NO narrowing of medulla clubbing may have acroosteolysis
Prognosis: | self-limiting = progression ceases after several years |
DDx: | hypertrophic pulmonary osteoarthropathy, thyroid acropachy |
Paget Disease
= OSTEITIS DEFORMANS
= multifocal chronic skeletal disease characterized by disordered and exaggerated bone remodeling
Etiology: ? chronic paramyxoviral infection Prevalence: 3% of individuals >40 years; 10% of persons >80 years; higher prevalence in northern latitudes; 2nd most common disease (after osteoporosis) affecting older individuals Age: Caucasian >55 years (in 3%); >85 years (in 10%); unusual <40 years; M:F = 2:1 Histo: increased resorption + increased bone formation; newly formed bone is abnormally soft with disorganized trabecular pattern ( mosaic pattern ) causing deformity
P.145
ACTIVE PHASE = OSTEOLYTIC PHASE
= intense osteoclastic activity = aggressive bone resorption with lytic lesions
Path: replacement of hematopoietic bone marrow by fibrous connective tissue with numerous large vascular channels osteoporosis circumscripta of skull flame-shaped radiolucency
MIDDLE / MIXED PHASE (common)
= decreased osteoclastic activity + increased osteoblastic activity
coexistence of lytic + sclerotic phases
INACTIVE / LATE PHASE = QUIESCENT PHASE
= diminished osteoblastic activity with decreased bone turnover
Path: loss of excessive vascularity osteosclerosis + cortical accretion (eg, ivory vertebral body)
asymptomatic (1/5 3/4)
fatigue
enlarged hat size
peripheral nerve compression
neurologic disorders from compression of brainstem (basilar invagination)
hearing loss, blindness, facial palsy (narrowing of neural foramina) rare
pain from
primary disease process rare
pathologic fracture
malignant transformation
degenerative joint disease / rheumatic disorder aggravated by skeletal deformity
local hyperthermia of overlying skin
high-output congestive heart failure from markedly increased perfusion (rare)
increased alkaline phosphatase (increased bone formation)
hydroxyproline increased (increased bone resorption)
normal serum calcium + phosphorus
Sites: usually polyostotic + asymmetric; pelvis (75%) > lumbar spine > thoracic spine > proximal femur > calvarium > scapula > distal femur > proximal tibia > proximal humerus Sensitivity: scintigraphy + radiography (60%) scintigraphy only (27 94%) radiography only (13 74%) osseous expansion trabecular coarsening cortical thickening cystlike areas (fat-filled marrow cavity / blood-filled sinusoids / liquefactive degeneration + necrosis of proliferating fibrous tissue) @ Skull (involvement in 29 65%)
inner + outer table involved diploic widening osteoporosis circumscripta = well-defined lysis, most commonly in calvarium anteriorly, occasionally in long bones (destructive active stage) cotton wool appearance = mixed lytic + blastic pattern of thickened calvarium (late stage) basilar impression with encroachment on foramen magnum deossification + sclerosis in maxilla sclerosis of base of skull
@ Long bones (almost invariable at end of bone; rarely in diaphysis)
candle flame / blade of grass lysis = advancing tip of V-shaped lytic defect in diaphysis of long bone originating in subarticular site (CHARACTERISTIC) lateral curvature of femur, anterior curvature of tibia (commonly resulting in fracture)
@ Ribs (1 4%)
@ Small / flat bones
bubbly destruction + periosteal successive layering
@ Pelvis
thickened trabeculae in sacrum, ilium; rarefaction in central portion of ilium thickening of iliopectineal line acetabular protrusion (DDx: metastatic disease not deforming) + secondary degenerative joint disease
@ Spine (upper cervical, low dorsal, midlumbar)
lytic / coarse trabeculations at periphery of bone picture-frame vertebra = bone-within-bone appearance = enlarged square vertebral body with reinforced peripheral trabeculae + radiolucent inner aspect, typically in lumbar spine ivory vertebra = blastic vertebra with increased density ossification of spinal ligaments, paravertebral soft tissue, disk spaces
Bone scan (94% sensitive):
usually markedly increased uptake (symptomatic lesions strikingly positive due to increased blood flow + osteoblastic activity) normal scan in some sclerotic burned-out lesions marginal uptake in lytic lesions enlargement + deformity of bones
Bone marrow scan:
sulfur colloid bone marrow uptake is decreased (marrow replacement by cellular fibrovascular tissue)
MR:
Indications: imaging of complications (spinal stenosis, basilar impression, tumor staging) areas of decreased signal intensity within marrow on T1WI + increased intensity on T2WI (= fibrovascular tissue resembling granulation tissue) hypointense area / area of signal void on T1WI + T2WI (cortical thickening, coarse trabeculation) reduction in size + signal intensity of medullary cavity (replacement of high-signal-intensity fatty marrow by increased medullary bone formation) focal areas of higher signal intensity than fatty marrow (= cystlike fat-filled marrow spaces) widening of bone
Cx:
Associated neoplasia (0.7 1 20%)
sarcomatous transformation into osteosarcoma (22 90%), fibrosarcoma /malignant fibrous histiocytoma (29 51%), chondrosarcoma (1 15%)
osteolysis in pelvis, femur, humerus Prognosis: <10% 5-year survival
multicentric giant cell tumor (3 10%)
lytic expansile lesion in skull, facial bones
lymphoma, plasma cell myeloma
P.146
Insufficiency fracture
banana fracture = tiny horizontal cortical infractions on convex surfaces of lower extremity long bones (lateral bowing of femur, anterior bowing of tibia);
compression fractures of vertebrae (soft bone despite increased density)
Neurologic entrapment
basilar impression with obstructive hydrocephalus + brainstem compression + syringomyelia
spinal stenosis with extradural spinal block (osseous expansion / osteosarcoma / vertebral retropulsion owing to compression fracture)
Early-onset osteoarthritis
Pathogenesis: altered biomechanics across affected articulations
Rx: | calcitonin, biphosphonates, mithramycin |
Detection of recurrence:
in 1/3 detected by bone scan
in 1/3 detected by biomarkers (alkaline phosphatase, urine hydroxyproline)
in 1/3 by scan + biomarkers simultaneously
diffuse (most common) / focal increase in tracer uptake extension of uptake beyond boundaries of initial lesion
DDx: | osteosclerotic metastasis, osteolytic metastasis, Hodgkin disease, vertebral hemangioma |
Paraosteoarthropathy
= HETEROTOPIC BONE FORMATION = ECTOPIC OSSIFICATION = MYOSITIS OSSIFICANS
Common complication following surgical manipulation, total hip replacement (62%) and chronic immobilization (spinal cord injury / neuromuscular disorders)
Mechanism: pluripotent mesenchymal cell lays down matrix for formation of heterotopic bone similar to endosteal bone Causes: para- / quadriplegia (40 50%), myelomeningocele, poliomyelitis, severe head injury, cerebrovascular disease, CNS infections (tetanus, rabies), surgery (commonly following total hip replacement) Evolution: calcifications seen 4 10 weeks following insult; progression for 6 14 months; trabeculations by 2 3 months; stable lamellar bone ankylosis in 5% by 12 18 months largest quantity of calcifications around joints, especially hip, along fascial planes disuse osteoporosis of lower extremities renal calculi (elevation of serum calcium levels) Radiographic grading system (Brooker):
0 no soft-tissue ossification
I separate small foci of ossification
II >1 cm gap between opposing bone surfaces of heterotopic ossifications
III <1 cm gap between opposing bone surfaces
IV bridging ossification
Bone scan:
tracer accumulation in ectopic bone assessment of maturity for optimal time of surgical resection (indicated by same amount of uptake as normal bone)
Cx: | ankylosis in 5% |
Rx: | 1000 2000 rad within 4 days following surgical removal |
Phenylketonuria
High incidence of x-ray changes in phenylalanine-restricted infants:
metaphyseal cupping of long bones (30 50%), especially wrist calcific spicules extending vertically from metaphysis into epiphyseal cartilage (DDx to rickets) sclerotic metaphyseal margins osteoporosis delayed skeletal maturation
DDx: | homocystinuria |
Phosphorus Poisoning
Etiology:
ingestion of metallic phosphorus (yellow phosphorus)
treatment of rachitis or TB with phosphorized cod liver oil
Location: long tubular bones, ilium
multiple transverse lines (intermittent treatment with phosphorus) lines disappear after some years
Pierre Robin Syndrome
May be associated with: | CHD, defects of eye and ear, hydrocephalus, microcephaly |
glossoptosis
micrognathia = hypoplastic receding mandible arched cleft palate rib pseudarthrosis
Cx: | airway obstruction (relatively large tongue), aspiration |
Pigmented Villonodular Synovitis
= PVNS = benign inflammatory lesion with extensive intraarticular highly vascular synovial proliferation / benign tumor of histiocytic origin /
Cause: frequently history of antecedent trauma Path: many villous / frondlike synovial proliferations Histo: (1) hyperplasia of undifferentiated connective tissue with multinucleated large cells ingesting hemosiderin / lipoid (foam / giant cells) (2) villonodular appearance of synovial membrane fibrosis (3) pressure erosion / invasion of adjoining bone Age: mainly 3rd 4th decade (range 12 68 years); 50% <40 years; M:F=1:1 hemorrhagic chocolate / serosanguinous / xanthochromic joint effusion without trauma
insidious onset of swelling, pain of long duration
joint stiffness with decreased range of motion, joint locking
Location: knee (80%) > hip > ankle > shoulder > elbow > tarsal + carpal joints; predominantly monoarticular (DDx: degenerative arthritis) soft-tissue swelling around joint (effusion + synovial proliferation): P.147
joint effusion in knee, but not relevant in other joints
dense soft tissues (hemosiderin deposits) subchondral pressure erosion (56%) at margins of joint on both sides of joint multiple sites of irregular cystlike radiolucent defects due to invasion of bone NO calcifications, osteoporosis, joint space narrowing (until late) CT:
small radiographically invisible erosions juxtaarticular soft-tissue mass with high attenuation
MR:
lobulated intraarticular masses of synovial tissue in a joint with effusion scalloping / truncation of prefemoral fat pad predominantly low signal intensity on all sequences (due to presence of iron) is CHARACTERISTIC often heterogeneous low + high signal intensity on T2WI: marked signal loss in periphery of lesions (magnetic susceptibility effect of hemosiderin) DDx: hemosiderin deposits in other diseases (eg, rheumatoid arthritis) high-signal intensity areas (due to fat, effusion, edema, inflammation)
Rx: | synovectomy (50% recurrence rate), arthrodesis, arthroplasty, radiation |
DDx: | (1) Degenerative / traumatic arthritis |
(2) Synovial sarcoma (solitary calcified mass outside joint) | |
(3) Sclerosing hemangioma | |
(4) Benign xanthoma | |
(5) Xanthogranuloma |
Intraarticular Localized Nodular Synovitis
= synovial lining without hemosiderin
Tenosynovial Giant Cell Tumor
= localized form of PVNS only involving the tendon sheath
Poland Syndrome
May be associated with: | aplasia of mamilla / breast |
Autosomal recessive
unilateral absence of the sternocostal head of the pectoralis major muscle ipsilateral syndactyly + brachydactyly rib anomalies
Poliomyelitis
osteoporosis soft-tissue calcification / ossification intervertebral disk calcification rib erosion commonly on superior margin of 3rd + 4th rib (secondary to pressure from scapula) bamboo spine (resembling ankylosing spondylitis) sacroiliac joint narrowing
Popliteal Cyst
= BAKER CYST
= synovial cyst in the posterior aspect of knee joint communicating with posterior joint capsule
Prevalence: 19% in general orthopedic patients, 61% in patients with rheumatoid arthritis Pathophysiology:
formed by escape of synovial effusion into one of the bursae; fluid trapped by one-way valvular mechanism
Bunsen-type valve = expanding cyst compresses the communicating channel
ball-type valve = ball composed of fibrin + cellular debris plugs the communication channel
Etiology:
Arthritis (rheumatoid arthritis most common)
Internal derangement (meniscal / anterior cruciate ligament tears)
Pigmented villonodular synovitis
pseudothrombophlebitis syndrome (= pain + swelling in calf)
cellulitis (after leakage / rupture)
Location:
gastrocnemius-semimembranosus bursa = posterior to gastrocnemius muscle at level of medial condyle
supralateral bursa = between lateral head of gastrocnemius muscle + distal end of biceps muscle superior to lateral condyle (uncommon)
popliteal bursa = beneath lateral meniscus + anterior to popliteal muscle (uncommon)
communication with bursa (documented on arthrogram) hypointense collection on T1WI + hyperintense on T2WI Types:
Intact cyst
smooth contour
Dissected cyst
smooth contour extending along fascial planes (usually between gastrocnemius + soleus)
Ruptured cyst
leakage into calf tissues
DDx of other synovial cysts about the knee:
Meniscal cyst (at lateral / medial side of joint line; associated with horizontal cleavage tears)
Tibiofibular cyst (at proximal tibiofibular joint, which communicates with knee joint in 10%)
Cruciate cyst (surrounding anterior / posterior cruciate ligaments following ligamentous injury)
Progeria
= HUTCHINSON-GILFORD SYNDROME
= autosomal recessive inheritance; most commonly in populations with consanguineous marriages (Japanese, Jewish)
Age: shortly after adolescence; M:F = 1:1 characteristic habitus + stature:
symmetric retardation of growth
absent adolescent growth spurt
dwarf with short stature + light body weight
spindly extremities with stocky trunk
beak-shaped nose + shallow orbits
premature senescence:
birdlike appearance
graying of hair + premature baldness
hyperpigmentation
voice alteration
diffuse arteriosclerosis
bilateral cataracts
osteoporosis
scleroderma-like skin changes:
P.148
atrophic skin + muscles
circumscribed hyperkeratosis
telangiectasia
tight skin
cutaneous ulcerations
localized soft-tissue calcifications
endocrine abnormalities:
diabetes
hypogonadism
generalized osteoporosis
@ Skull
thin cranial vault delayed sutural closure + wormian bones hypoplastic facial bones (maxilla + mandible)
@ Chest
narrow thorax + slender ribs progressive resorption with fibrous replacement of outer portions of thinned clavicles (HALLMARK) coronary artery + heart valve calcifications with cardiac enlargement
@ Extremities & joints
short + slender long bones coxa valga valgus of humeral head acroosteolysis of terminal phalanges (occasionally) flexion + extension deformities of toes (hallux valgus, pes planus) excessive degenerative joint disease of major + peripheral joints neurotrophic joint lesions (feet) widespread osteomyelitis + septic arthritis (hands, feet, limbs)
@ Soft tissue
soft-tissue atrophy of extremities soft-tissue calcifications around bony prominences (ankle, wrist, elbow, knee) peripheral vascular calcifications = premature atherosclerosis
Prognosis: | most patients die in their 30s / 40s from complications of arteriosclerosis (myocardial infarction, stroke) or neoplasm (sarcoma, meningioma, thyroid carcinoma) |
DDx: | Cockayne syndrome (mental retardation, retinal atrophy, deafness, family history) |
Pseudoachondroplasia
normal face + head
limb shortening irregular epiphyses scoliosis coxa vara marked shortening of bones in hands + feet
Pseudofractures
= LOOSER LINES = LOOSER ZONES = OSTEOID SEAMS = MILKMAN SYNDROME
= insufficiency stress fractures + nonunion (incomplete healing due to mineral deficiency)
Path: area of unmineralized woven bone occurring at sites of mechanical stress / nutrient vessel entry Associated with:
Osteomalacia / rickets
Paget disease ( banana fracture )
Osteogenesis imperfecta tarda
Fibrous dysplasia
Organic renal disease in 1%
Renal tubular dysfunction
Congenital hypophosphatasia
Congenital hyperphosphatasia ( juvenile Paget disease )
Vitamin D malabsorption / deficiency
Neurofibromatosis
mnemonic: POOF Paget disease
Osteomalacia
Osteogenesis imperfecta
Fibrous dysplasia
Common locations:
scapulae (axillary margin, lateral + superior margin), medial femoral neck + shaft, pubic + ischial rami, ribs, lesser trochanter, ischial tuberosity, proximal 1/3 of ulna, distal 1/3 of radius, phalanges, metatarsals, metacarpals, clavicle
typically bilateral + symmetric at right angles to bone margin paralleled by marginal sclerosis in later stages healing fracture with little or no callus response 2 3-mm stripe of lucency at right angle to cortex (= osteoid seams formed within stress-induced infractions (PATHOGNOMONIC) + nonunion (= incomplete healing due to mineral deficiency)
Pseudohypoparathyroidism
= PHypoPT = congenital X-linked dominant abnormality with renal + skeletal resistance to PTH due to
end- organ resistance
presence of antienzymes
defective hormone
May be associated with: hyperparathyroidism due to hypocalcemia; F > M
short obese stature, round face
mental retardation
corneal + lenticular opacity
abnormal dentition (hypoplasia, delayed eruption, excessive caries)
hypocalcemia + hyperphosphatemia (resistant to PTH injection)
normal levels of PTH
brachydactyly in bones in which epiphysis appears latest (metacarpal, metatarsal bones I, IV, V) (75%) accelerated epiphyseal maturation resulting in dwarfism + coxa vara / valga Differential Signs between PHypoPT and PPHypoPT
PHypoPT PPHypoPT calcification of basal ganglia 44% 8% soft-tissue calcifications 55% 40% metacarpal shortening (4 + 5 always involved) 75% 90% metatarsal shortening (3 + 4 involved) 70% 99% multiple diaphyseal exostoses (occasionally) calcification of basal ganglia + dentate nucleus calcification / ossification of skin + subcutaneous tissue
P.149
Pseudopseudohypoparathyroidism
= PPHypoPT = different expression of same familial disturbance with identical clinical + radiographic features as pseudohypoparathyroidism but normocalcemic
Cause: end-organ resistance to PTH short stature, round facies NO blood chemical changes (normal calcium + phosphorus)
normal response to injection of PTH
brachydactyly
Pseudoxanthoma Elasticum
= recessive hereditary systemic disorder characterized by degeneration of elastic tissue
@ Skin
redundant skin folds, particularly in flexor regions
yellowish xanthomatous papules
large amorphous calcific deposits in soft tissue about the joints
@ Eyes
diminished visual acuity due to alteration of chorioretinal structure
angioid streaks = reddish brown serrated lines extending from optic disk in a spoke-wheel fashion
@ Arteries
claudication + decreased pulses
Histo: tissue degeneration of internal elastic lamina + medial thickening lobulated appearance of arteries (similar to fibromuscular hyperplasia) aneurysm formation vessel calcification at early age
Cx: | GI tract hemorrhage |
Psoriatic Arthritis
Uncommon disease involving synovium + ligamentous attachments with propensity for sacroiliitis / spondylitis classified as seronegative spondyloarthropathy 6/c
Incidence: 20% of patients with psoriasis (peripheral arthritis in 5%, sacroiliitis in 29%, peripheral arthritis + sacroiliitis in 10%) Path: synovial inflammation (less prominent than in rheumatoid arthritis) with early fibrosis of proliferative synovium; bony proliferation at joint margins / tendon insertions / subperiosteum Types:
true psoriatic arthritis (31%)
psoriatic arthritis resembling rheumatoid arthritis (38%)
concomitant rheumatoid + psoriatic arthritis (31%)
skin rash precedes / develops simultaneously with onset of arthritis in 85%
Arthritis antedates dermatological changes by an interval of up to 20 years!
pitting, discoloration, hyperkeratosis, subungual separation, ridging of nails (in 80%)
positive HLA-B27 in 80%
negative rheumatoid factor
Location: widely variable distribution + asymmetry with involvement of lower + upper extremities; distinctive pattern: terminal interphalangeal joints, ray distribution, unilateral polyarticular asymmetrical distribution NO / minimal juxtaarticular osteoporosis (early stage); frequent osteoporosis (later stages) marginal erosions periosteal reaction frequent intraarticular osseous excrescences @ Hand + foot
Target area: DIP, PIP, MCP sausage digit = soft-tissue swelling of entire digit destruction of distal interphalangeal joints (erosive polyarthritis) + osseous resorption bony ankylosis (10%) pencil-in-cup deformity = erosions with ill-defined margins + adjacent proliferation of periosteal new bone (CHARACTERISTIC) ivory phalanx = sclerosis of terminal phalanx (28%) destruction of interphalangeal joint of 1st toe with exuberant periosteal reaction + bony proliferation at distal phalangeal base (PATHOGNOMONIC) poorly defined diffuse new bone formation at attachment of Achilles tendon + plantar aponeurosis erosions at superior / posterior margin of calcaneus (20%) acroosteolysis (occasionally)
@ Axial skeleton
floating osteophyte = large bulky vertically oriented paravertebral soft-tissue ossification (AP view): ill-defined excrescence sweeping across the diskovertebral junction from midportion of one vertebra to the next Location: lower cervical, thoracic, upper lumbar spine; asymmetric / unilateral
squaring of vertebrae in lumbar region sacroiliitis (40%) = (most commonly) bilateral + symmetric sacroiliac joint widening, increased density, fusion apophyseal joint narrowing + sclerosis atlantoaxial subluxation + odontoid abnormalities
DDx: | (1) Reiter syndrome (affects only lower extremity) |
(2) Ankylosing spondylitis | |
(3) Rheumatoid arthritis (bilaterally symmetric well-defined erosions, juxtaarticular osteoporosis) |
Pyknodysostosis
= MAROTEAUX-LAMY DISEASE
= autosomal recessive inherited disease; probably variant of cleidocranial dysostosis
Cause: mutation in cathepsin-K gene Age: children; M:F = 2:1 dwarfism
mental retardation (10%)
widened hands + feet
dystrophic nails
yellowish discoloration of teeth
characteristic facies (beaked nose, receding jaw)
brachycephaly + platybasia wide cranial sutures, wormian bones thick skull base hypoplasia of mandible + obtuse mandibular angle hypoplasia + nonpneumatization of paranasal sinuses nonsegmentation of C1/2 and L5/S1 generalized increased density of long bones with thickened cortices (resembling osteopetrosis but with preservation of medullary canal) clavicular dysplasia hypoplastic tapered terminal tufts (=acroosteolysis) multiple spontaneous fractures
P.150
DDx: | (1) Osteopetrosis (no dwarfism, no mandibular / skull abnormality, no phalangeal hypoplasia, no transverse metaphyseal bands, anemia, Erlenmeyer flask deformity; bone-within-bone appearance) |
(2) Cleidocranial dysostosis (no dense bones / terminal phalangeal hypoplasia, short stature) |
Radiation Injury to Bone
Pathogenesis: | vascular compromise with obliterative endarteritis + periarteritis followed by damage to osteoblasts + osteoclasts with decreased matrix production (growing bone + periosteal new bone most sensitive) |
Dose effects:
depend on age of patient, absorbed dose, size of radiation field, beam energy, fractionation
>300 rad: microscopic changes >400 rad: growth retardation <600 1200 rad: histological recovery retained >1200 rad: pronounced cellular damage to chondrocytes; bone marrow atrophy + cartilage degeneration after >6 months; vascular fibrosis
FOCAL MARROW DEPLETION.
Pathophysiology: marrow edema, vascular congestion, suppressed hematopoiesis; replacement of marrow elements by fibrosis + fat (complete by 3 months) homogeneous high-intensity signal within radiation port on T1WI occasionally bandlike appearance characterized by peripheral zone of low signal intensity (red marrow) and a central zone of high signal intensity (fatty marrow) on T1WI
BONE GROWTH DISTURBANCE
@ Appendicular skeleton
joint space widening (due to cartilage hypertrophy) after 8 10 months growth plate widening in 1 2 months, often returning to normal by 6 months permanent alteration in bone length / size (due to premature fusion of physis) metaphyseal bowing sclerotic metaphyseal bands metaphyseal irregularity + fraying resembling rickets longitudinal striations overtubulation (= abnormal narrowing of the diaphyseal shaft) Cx: slippage of femoral / humeral epiphysis ischemic necrosis (after doses of >25 Gy)
@ Axial skeleton (dose of <15 Gy)
bone-within-bone appearance after 9 12 months irreversible scalloping + irregularity of vertebral endplate with decreased height of vertebra (= failure of vertical growth)
scoliosis concave to the side of irradiation (due to asymmetric vertebral growth + muscular fibrosis) hypoplasia of ilium + ribs acetabular dysplasia, coxa vara / valga
RADIATION OSTEITIS = OSTEORADIONECROSIS
= RADIATION NECROSIS
= bone mottling due to osteopenia + coarse trabeculation + focally increased bone density (due to attempts of osseous repair with deposition of new bone on ischemic trabeculae)
Dose: >6,000 cGy in adults; >2,000 cGy in children Time of onset: 1 3 years following radiation therapy Location: mandible, ribs, clavicle, humerus, spine, pelvis, femur focal lytic area with abnormal bone matrix: radiolucency confined to radiation field with narrow zone of transition
periostitis increased fragility with sclerosis (= pathologic insufficiency fracture) cortical thinning from chronic infection MR:
increased intensity of spinal bone marrow on T1WI + T2WI corresponding to radiation port (fatty infiltration)
NUC:
bone scan with decreased uptake in radiation field Cx: increased susceptibility of irradiated bone to infection DDx: recurrent malignancy, radiation-induced sarcoma (soft-tissue mass), infection
BENIGN NEOPLASM
Most likely in patients <2 years of age at treatment; with doses of 1600 6425 rads
Latent period: 1.5 5 14 years Osteochondroma = exostosis (exclusively in children under 2 years of age during treatment)
Osteoblastoma
MALIGNANT NEOPLASM
= RADIATION-INDUCED SARCOMA
Latency period: 3 55 (average of 11 14) years Minimum dose: 1,660 3,000 rad Criteria: (a) malignancy occurring within irradiated field (b) latency period of >5 years (c) histologic proof of sarcoma (d) microscopic evidence of altered histology of the original lesion Histo: 1. Osteosarcoma (90%) = 4 11% of all osteogenic sarcomas 2. Fibrosarcoma > chondrosarcoma > malignant fibrous histiocytoma pain, soft-tissue mass, rapid progression of lesion
Reflex Sympathetic Dystrophy
= CAUSALGIA = SHOULDER-HAND SYNDROME = POSTTRAUMATIC OSTEOPOROSIS = SUDECK DYSTROPHY
= serious + potentially disabling condition with poorly understood origin + cause
Etiology:
Trauma in >50% (fracture, frostbite; may be trivial)
Affects 0.01% of all trauma patients
Idiopathic in 27% (immobilization, infection)
Myocardial ischemia in 6%
CNS disorders in 6%
Affects 12 21% of patients with hemiplegia
Diskogenic disease in 5%
burning pain, tenderness, allodynia, hyperpathia
soft-tissue swelling pitting edema out of proportion to degree of injury
dystrophic skin + nail changes
sudomotor changes: hyperhidrosis + hypertrichosis
vasomotor instability (Raynaud phenomenon, local vasoconstriction / -dilatation)
end-stage (after 6 12 months): contractures, atrophy of skin + soft tissues
Location: hands and feet distal to injury periarticular soft-tissue swelling patchy osteopenia (50%) as early as 2 3 weeks after onset of symptoms (DDx: disuse osteopenia) generalized osteopenia = ground-glass appearance with endosteal + intracortical excavation: subperiosteal bone resorption lysis of juxtaarticular + subchondral bone preservation of joint space (DDx: rheumatoid / septic arthritis) NUC (3-phase bone scan):
increased flow + increased blood pool + increase in periarticular uptake on delayed images in affected part (60%) diminished flow / delayed uptake (15 20%)
P.151
Rx: | sympathetic block, - / -adrenergic blocking agents, nonsteroidal antiinflammatory drugs, radiation therapy, hypnosis, acupuncture, acupressure, transcutaneous nerve stimulation, physiotherapy, calcitonin, corticosteroids, early mobilization |
Reiter Syndrome
= triad of
arthritis
uveitis
urethritis; M:F = 98:2
Types:
endemic (venereal)
epidemic (postdysenteric)
history of sexual exposure / diarrhea 3 11 days before onset of urethritis
mucocutaneous lesions (keratosis blennorrhagia, balanitis circinata sicca)
uveitis, conjunctivitis
positive HLA-B27 in 76%
Location: asymmetric mono- / pauciarticular polyarthritis articular soft-tissue swelling + joint space narrowing in 50% (particularly knees, ankles, feet) widening + inflammation of Achilles + patella tendons fluffy periosteal reaction (DISTINCTIVE) at metatarsal necks, proximal phalanges, calcaneal spur, tibia + fibula at ankle and knee juxtaarticular osteoporosis (rare in acute stage) CHRONIC CHANGES:
recurrent joint attacks in a few cases
calcaneal spur at insertion of plantar fascia + Achilles tendon periarticular deossification marginal erosions, loss of joint space bilateral sacroiliac changes indistinguishable from ankylosing / psoriatic spondylitis (in 10 40%) paravertebral ossification = isolated floating osteophyte usually in thoracolumbar area
Cx: | gastric ulcer + hemorrhage; aortic incompetence; heart block; amyloidosis |
Relapsing Polychondritis
= rare disorder characterized by generalized recurring inflammation + destruction of cartilage in joints, ears, nose, larynx, airways
Etiology: acquired metabolic disorder (? abnormal acid mucopolysaccharide metabolism) / hypersensitivity / autoimmune process (antibodies directed against type II collagen) Histo: loss of cytoplasm in chondrocytes; plasma cell + lymphocyte infiltration Age: 40 60 years (no age predilection) nasal chondritis = saddle-nose deformity bilateral auricular chondritis = swollen + tender ears, cauliflower ears
hearing loss (obstruction of external auditory meatus / audiovestibular damage)
ocular inflammation
cough, hoarseness, dyspnea (collapse of trachea)
nonerosive seronegative inflammatory polyarthritis = arthralgia
@ Head
calcification of pinna of ear
@ Chest
manubriosternal / costochondral arthropathy (30%)
@ Respiratory tract (in up to 70%)
ectasia + collapsibility (cartilaginous destruction) of trachea and mainstem bronchi with focal thickening (mucosal edema) + luminal narrowing (fibrosis) bronchiectasis generalized + localized emphysema
@ Cardiovascular (in 15 46%)
aortic aneurysm (4 10%), mostly in ascending aorta, may be multiple / dissecting aortic / mitral valve insufficiency (8%) systemic vasculitis (13%)
@ Bone
periarticular osteoporosis erosive changes in carpal bones resembling rheumatoid arthritis soft-tissue swelling around joints + styloid process of ulna erosive irregularities in sacroiliac joints disk space erosion + increased density of articular plates
Rx: | corticosteroids, immunosuppression |
Prognosis: | 74% 5-year survival rate; 55% 10-year survival rate; median survival time of 11 years; airway complications account for >50% of deaths |
P.152
Renal osteodystrophy
= constellation of musculoskeletal abnormalities that occur with chronic renal failure as a combination of
osteomalacia (adults) / rickets (children)
2 HPT with osteitis cystica fibrosa + soft-tissue calcifications
osteosclerosis
soft-tissue + vascular calcifications
Classification:
Glomerular form = acquired renal disease: chronic glomerulonephritis (common)
Tubular form = congenital renal osteodystrophy:
Vitamin D resistant rickets = hypophosphatemic rickets
Fanconi syndrome = impaired resorption of glucose, phosphate, amino acids, bicarbonate, uric acid, sodium, water
Renal tubular acidosis
Pathogenesis:
Renal insufficiency causes a decrease in vitamin D conversion into the active 1,25(OH)2D3 (done by 25-OH-D-1-a hydroxylase, which is exclusive to renal tissue mitochondria); vitamin D deficiency slows intestinal calcium absorption; vitamin D resistance predominates and calcium levels stay low (Ca P product remains almost normal secondary to hyperphosphatemia); low calcium levels lead to OSTEOMALACIA; additional factors responsible for osteomalacia are inhibitors to calcification produced in the uremic state, aluminum toxicity, dysfunction of hepatic enzyme system
Renal insufficiency with diminished filtration results in phosphate retention; maintenance of Ca P product lowers serum calcium directly, which in turn increases PTH production (2 HPT); 2 HPT predominates associated with mild vitamin D resistance and leads to an increase in Ca P product with SOFT-TISSUE CALCIFICATION in kidney, lung, joints, bursae, blood vessels, heart as well as OSTEITIS FIBROSA
Mixture of (a) and (b): increased serum phosphate inhibits vitamin D activation via feedback regulation
phosphate retention
hypocalcemia
OSTEOPENIA (in 0 25 83%)
= diminution in number of trabeculae + thickening of stressed trabeculae = increased trabecular pattern
Cause: combined effect of Osteomalacia (reduced bone mineralization due to acquired insensitivity to vitamin D / antivitamin D factor)
Osteitis fibrosa cystica (bone resorption)
Osteoporosis (decrease in bone quantity)
Contributing factors:
chronic metabolic acidosis, poor nutritional status, pre- and posttransplantation azotemia, use of steroids, hyperparathyroidism, low vitamin D levels
Cx: fracture predisposition (lessened structural strength) with minor trauma / spontaneously; fracture prevalence increases with duration of hemodialysis + remains unchanged after renal transplantation Site: vertebral body (3 25%), pubic ramus, rib (5 25%)
Milkman fracture / Looser zones (in 1%) metaphyseal fractures Prognosis: osteopenia may remain unchanged / worsen after renal transplantation + during hemodialysis
RICKETS (children)
Cause: in CRF normal vessels fail to develop in an orderly way along cartilage columns in zone of provisional calcification; this results in disorganized proliferation of the zone of maturing + hypertrophying cartilage and disturbed endochondral calcification Location: most apparent in areas of rapid growth such as knee joints diffuse bone demineralization widening of growth plate irregular zone of provisional calcification metaphyseal cupping + fraying bowing of long bones, scoliosis diffuse concave impression at multiple vertebral end plates, basilar invagination slipped epiphysis (10%): capital femoral, proximal humerus, distal femur, distal radius, heads of metacarpals + metatarsals general delay in bone age
SECONDARY HPT (in 6 66%)
Cause: inability of kidneys to adequately excrete phosphate leads to hyperplasia of parathyroid chief cells (2 HPT); excess PTH affects the development of osteoclasts, osteoblasts, osteocytes hyperphosphatemia
hypocalcemia
increased PTH levels
subperiosteal, cortical, subchondral, trabecular, endosteal, subligamentous bone resorption osteoclastoma = brown tumor = osteitis fibrosa cystica in 1.5 1.7% (due to PTH-stimulated osteoclastic activity; more common in 1 HPT) periosteal new-bone formation (8 25%) chondrocalcinosis (more common in 1 HPT)
OSTEOSCLEROSIS (9 34%)
One of the most common radiologic manifestations; most commonly with chronic glomerulonephritis; may be the sole manifestation of renal osteodystrophy diffuse chalky density: thoracolumbar spine in 60% (rugger jersey spine); also in pelvis, ribs, long bones, facial bones, base of skull (children) Prognosis: may increase / regress after renal transplantation
SOFT-TISSUE CALCIFICATIONS
= Uremic tumoral calcinosis = secondary tumoral calcinosis = pseudotumor calcinosis
Most frequent cause of a periarticular calcified mass! Cause:?
metastatic
secondary to hyperphosphatemia (solubility product for calcium + phosphate [Ca2+ PO4-2] exceeds 60 75 mg/dL in extracellular fluid), hypercalcemia, alkalosis with precipitation of calcium salts
dystrophic
secondary to local tissue injury
Location:
arterial (27 83%):
in medial + intimal elastic tissue
Site: dorsal pedis a., forearm, hand, wrist, leg pipestem appearance without prominent luminal involvement
periarticular (0.5 1.2%):
multifocal, frequently symmetric, may extend into adjacent joint
chalky fluid / pastelike material
inflammatory response in surrounding tenosynovial tissue
discrete cloudlike dense areas fluid-fluid level in tumoral calcinosis Prognosis: often regresses with treatment
visceral (79%): heart, lung, stomach, kidney
fluffy amorphous tumoral calcification
P.153
Rx: | 1. Decrease of phosphorus absorption in bowel (in hyperphosphatemia) |
2. Vitamin D3 administration (if vitamin D resistance predominates) | |
3. Parathyroidectomy for 3 HPT (= autonomous HPT) |
Dialysis-related Disorders
Osteomyelitis
Osteonecrosis
Crystal deposition
Destructive spondyloarthropathy
Amyloidosis
Dialysis cysts
Congenital Renal Osteodystrophy
Vitamin D Resistant Rickets
= PHOSPHATE DIABETES = PRIMARY HYPOPHOSPHATEMIA = FAMILIAL HYPOPHOSPHATEMIC RICKETS
= rare X-linked dominant disorder of renal tubular reabsorption characterized by
impaired resorption of phosphate in proximal renal tubule (due to defect in renal brush-border membrane)
inappropriately low synthesis of 1,25-dihydroxy-vitamin D3 [1,25(OH)2D3] in renal tubules resulting in decreased intestinal resorption of calcium + phosphate
Age: <1 year
hypophosphatemia + hyperphosphaturia
elevated serum alkaline phosphatase
normal plasma + urine calcium
normal / low serum 1,25(OH)2D3
classic rachitic changes skeletal deformity, particularly bowed legs retarded bone age; dwarfism if untreated osteosclerosis / bone thickening (from overabundance of incompletely calcified matrix)
Rx: | phosphate infusion + large doses of vitamin D |
DDx: | vitamin-D deficient and dependent rickets (absence of muscle weakness + seizures + tetany) |
Fanconi Syndrome
Triad of
Hyperphosphaturia
Amino aciduria
Renal glucosuria (normal blood glucose)
Etiology: renal tubular defect
rickets, osteomalacia, osteitis fibrosa, osteosclerosis
Prognosis: | functional renal impairment likely when bone changes occur |
Rx: | large doses of vitamin D + alkalinization |
Renal Tubular Acidosis
systemic acidosis, bone lesions
rickets, osteomalacia, pseudofractures, nephrocalcinosis, osteitis fibrosa (rare) Lightwood syndrome = salt-losing nephritis (transient self-limited form)
NO nephrocalcinosis
Butler-Albright syndrome (severe form)
nephrocalcinosis
Rheumatoid arthritis
= chronic systemic connective tissue disease
= type III hypersensitivity = delayed hypersensitivity
= immune complex disease (= formation of antigen-antibody complexes with complement fixation) with T-cell mediated autoreactivity against a joint component
Prevalence: 0.5 1.0% of population Cause: genetic predisposition;? reaction to antigen from Epstein-Barr virus / certain strains of E. coli Peak age: 45 65 years; M:F = 1:3 if <40 years; M:F = 1:1 if >40 years Pathogenesis:
injury to synovial endothelial cells; synovitis with synovial hyperplasia and pannus formation mediated by TNF- (tumor necrosis factor ) and IL-1 (interleukin 1) leads to invasion by local macrophages, fibroblasts, and activated lymphocytes; invasion of articular cartilage + bone by secretion of degrading enzymes (metalloproteinases)
Diagnostic Criteria of American Rheumatism Association (at least 4 criteria should be present):
morning stiffness for 1 hour before improvement
swelling of 3 joints, particularly of wrist, metacarpophalangeal or proximal interphalangeal joints for >6 weeks
symmetric swelling
typical radiographic changes
subcutaneous rheumatoid nodules
positive test for rheumatoid factor
morning stiffness
fatigue, weight loss, anemia
carpal tunnel syndrome
rheumatoid factor (positive in 85 94%) = IgM-antibody
= agglutination of sensitized sheep RBCs closely correlating with disease severity
false positive: normal (5%), asbestos workers with fibrosing alveolitis (25%), viral / bacterial / parasitic infection, other inflammatory diseases
antinuclear antibodies (positive in many)
LE cells (positive in some)
positive latex flocculation test
hormonal influence:
decrease in activity during pregnancy
men with RA have low testosterone levels
Location: bilateral symmetric involvement of >3 diarthrodial joints (polyarthritis) Symmetric arthritis of multiple small hand joints in >60% of patients at initial presentation
EARLY SIGNS:
MR & US (methods of choice):
synovial hyperemia (in acute disease + exacerbation of chronic disease) synovial swelling (edema + cellular infiltrates) pannus = tumorlike focal proliferation of inflammatory tissue with destruction of cartilage and bone pre-erosive subcortical cysts joint effusion bone marrow edema
Radiography (indirect & nonspecific):
fusiform periarticular soft-tissue swelling (result of effusion) paraarticular osteoporosis (inactivity due to pain + local inflammatory hyperthermia) translucent subchondral end plate widened joint space (synovial swelling + fluid) effacement of fat pads subcortical synovial cyst erosion (up to 47% within 1st year after onset) initially at bare area (= site of attachment of internal synovial layer of joint capsule to bone) due to lack of protective cartilage layer
LATE SIGNS:
concentric joint space narrowing (due to destruction of cartilage, formation of scar tissue, fibrosis) subluxation (due to laxity of capsule + ligaments from inflammatory destruction / due to capsular shrinkage from fibrosis + scar formation): mallet finger = droopy distal phalanx due to disrupted extensor tendon insertion site swan-neck deformity = hyperextension at PIP + flexion at DIP boutonni re deformity = flexion at PIP + hyperextension at DIP hitchhiker deformity = flexion at MCP + hyperextension at DIP
dislocation marked destruction + fractures of bone ends: intraarticular loose bodies rice bodies = subset of loose bodies resembling polished rice (made of sloughed fibrinogen-coated infarcted synovial tissue / precipitate of fibrin + fibronectin / core of mononuclear cells, blood cells and amorphous material)
bony ankylosis
@ Hand & wrist (typical)
Target areas:
all five MCP, PIP, interphalangeal joint of thumb, all wrist compartments (especially radiocarpal, inferior radioulnar, pisiform-triquetral joints); earliest changes seen in MCP 2 + 3, PIP 3
marginal + central bone erosions (less common in large joints); site of first erosion is classically base of proximal phalanx of 4th finger changes in the ulnar styloid + distal radioulnar joint (early sign) flexion + extension contractures with ulnar subluxation + dislocation
@ Cervical spine
erosions of odontoid process (1) between anterior arch of atlas + dens, (2) between transverse ligament of atlas + dens, (3) at tip of odontoid process anterior atlantoaxial subluxation (in >6%): >2.5 mm in adults, >4.5 mm in children during neck flexion cranial settling = odontoid process projects into skull base due to significant disease of atlanto-occipital and atlantoaxial joints lateral head tilt = lateral subluxation = asymmetry between odontoid process + lateral masses of atlas stepladder appearance of cervical spine due to subaxial subluxations + absence of osteophytosis: destruction + narrowing of disk spaces irregular vertebral body outlines erosion + destruction of zygapophyseal joints resorption of spinous processes
osteoporosis Cx: spinal cord compression
@ Ribs
erosion of superior margins of posterior portions of ribs 3 5
@ Shoulder
symmetric loss of glenohumeral joint space: marginal erosions at superolateral aspect of humeral head osteoporosis elevation of humeral heads = narrowing of acromiohumeral distance (2 to tear / atrophy of rotator cuff) Subluxations in rheumatoid arthritis
widened acromioclavicular joint: erosions at acromial + clavicular end tapered margins of distal clavicle
scalloped erosion on undersurface of distal clavicle opposite the coracoid process (attachment of coracoclavicular ligament)
P.155
@ Sacroiliac joint (rarely affected)
typically asymmetric unilateral distribution shallow erosions + mild sclerosis rare ankylosis
@ Hip (rarely affected)
often appears normal during early disease process pannus formation (MR imaging) symmetric loss of joint space with axial migration of femoral head marginal + central erosions, cysts, localized sclerosis decompression of joint effusion into iliopsoas bursa through weak anterior capsule displacing muscle + vasculature rupture of gluteal tendon protrusio acetabuli (from osteoporosis)
@ Knee
Location: medial + lateral femorotibial compartments; bilateral symmetric diffuse loss of joint space osteoporosis superficial + deep marginal + central erosions subchondral sclerosis (especially in tibia) synovial herniation + cysts (eg, popliteal cyst) varus / valgus angulation (due to crumbling of osteoporotic bone of tibia + ligamentous abnormalities) @ Foot (typical)
Target areas:
medial aspect of MT heads (2,3,4), medial + lateral aspect of MT5 (earliest sign); interphalangeal joints of foot (esp. great toe); midfoot joints; talonavicular, subtalar, tarsometatarsal joints; bilateral + symmetric
sinus tarsi syndrome = compression of tibial nerve
calcaneal plantar spur retrocalcaneal bursitis DDx: SLE, seronegative spondyloarthropathies (proliferative changes at bone + tendinous insertion sites, bony ankylosis)
EXTRA-ARTICULAR MANIFESTATIONS (76%)
Felty syndrome (<1%)
= rheumatoid arthritis (present for >10 years) + splenomegaly + neutropenia
Age: 40 70 years; F > M; rare in Blacks rapid weight loss
therapy refractory leg ulcers
brown pigmentation over exposed surfaces of extremities
Sj gren syndrome (15%)
= keratoconjunctivitis + xerostomia + rheumatoid arthritis
Pulmonary manifestations
pleural effusion, mostly unilateral, without change for months, usually not associated with parenchymal disease interstitial fibrosis with lower lobe predominance Prevalence: 2 9% of rheumatoid patients rheumatoid nodules (30%): well-circumscribed, peripheral, with frequent cavitation Caplan syndrome (= hyperimmune reactivity to silica inhalation with rapidly developing multiple pulmonary nodules) pulmonary hypertension secondary to arteritis
Subcutaneous nodules
(in 5 35% with active arthritis) over extensor surfaces of forearm + other pressure points (eg, olecranon) without calcifications (DDx to gout)
Cardiovascular involvement
Pericarditis (20 50%)
Myocarditis (arrhythmia, heart block)
Aortitis (5%) of ascending aorta aortic valve insufficiency
Rheumatoid vasculitis
= leukocytoclastic lesion of small venules mimicking periarteritis nodosa
polyneuropathy, cutaneous ulceration, gangrene, polymyopathy, myocardial / visceral infarction
Neurologic sequelae
Distal neuropathy (related to vasculitis)
Nerve entrapment (atlantoaxial subluxation, carpal tunnel syndrome, Baker cyst)
Lymphadenopathy (up to 25%)
splenomegaly (1 5%)
P.154
Cystic Rheumatoid Arthritis
= intraosseous cystic lesions as dominant feature
Pathogenesis: increased pressure in synovial space from joint effusion decompresses through microfractures of weakened marginal cortex into subarticular bone Increase in size + extent of cysts correlates with increased level of activity + absence of synovial cysts Age: as above; M:F = 1:1 seronegative in 50%
juxtaarticular subcortical lytic lesions with well-defined sclerotic margins relative lack of cartilage loss, osteoporosis, joint disruption
DDx: | gout (presence of urate crystals), pigmented villonodular synovitis (monoarticular) |
Juvenile Rheumatoid Arthritis
= rheumatoid arthritis in patients <16 years of age; M < F
morning stiffness, arthralgia
subcutaneous nodules (10%)
skin rash (50%)
fever, lymphadenopathy
Location: early involvement of large joints (hips, knees, ankles, wrists, elbows); later of hands + feet radiologic signs similar to rheumatoid arthritis (except for involvement of large joints first, late onset of bony changes, more ankylosis, wide metaphyses) periarticular soft-tissue swelling thinning of joint cartilage large cystlike lesions removed from articular surface (invasion of bone by inflammatory pannus); rare in children articular erosions at ligamentous + tendinous insertion sites joint destruction may resemble neuropathic joints juxtaarticular osteoporosis balloon epiphyses + gracile bones (epiphyseal overgrowth + early fusion with bone shortening secondary to hyperemia) @ Hand / foot
rectangular phalanges (periostitis + cortical thickening) ankylosis in carpal joints
@ Axial skeleton
Location: predominantly upper cervical spine ankylosis of cervical spine (apophyseal joints), sacroiliac joints decreased size of vertebral bodies + atrophic intervertebral disks subluxation of atlantoaxial joint (66%) thoracic spinal compression fractures
@ Chest
ribbon ribs pleural + pericardial effusions interstitial pulmonary lesions (simulating scleroderma, dermatomyositis) solitary pulmonary nodules, may cavitate Prognosis: complete recovery (30%); secondary amyloidosis
Clinical classification:
Juvenile-onset adult type (10%)
IgM RA factor positive; age 8 9; poor prognosis erosive changes; profuse periosteal reaction; hip disease with protrusio
Polyarthritis of the ankylosing spondylitic type
iridocyclitis; boys age 9 11 years peripheral arthritis; fusion of greater trochanter; complete fusion of both hips; heel spur
Still disease
systemic
polyarticular
pauciarticular + iridocyclitis (30%)
fever, rash, lymphadenopathy, hepatosplenomegaly; pericarditis, dwarfism
fatal kidney disease in 20%
Age: 2 4 and 8 11 years of age; M < F Location: involvement of carpometacarpal joints ( squashed carpi in adulthood), hind foot, hip (40 50%) periosteal reaction of phalanges; broadening of bones; accelerated bone maturation + early fusion (stunting of growth)
P.156
Rickets
= osteomalacia during enchondral bone growth
Age: 4 18 months Histo: zone of maturation has an increase in number of maturing cartilage cells with loss of normal columnar arrangement; zone of preparatory calcification does not form; failure of osteoid mineralization also in shafts so that osteoid production elevates periosteum irritability, bone pain, tenderness
craniotabes
rachitic rosary
bowed legs
delayed dentition
swelling of wrists + ankles
Location: metaphyses of long bones subjected to stress are particularly involved (wrists, ankles, knees); costochondral junction of ribs poorly mineralized irregular epiphyseal centers with delayed appearance axial widening of growth plate = increase in distance between end of shaft and epiphyseal center due to increased osteoid production (earliest changes) cupping + fraying of metaphysis with threadlike shadows into epiphyseal cartilage (weight-bearing bones) cortical spurs projecting at right angles to metaphysis coarse trabeculation (NO ground-glass pattern as in scurvy) periosteal reaction may be present deformities common (bowing of soft diaphysis, molding of epiphysis, fractures) bowing of long bones frontal bossing mnemonic: RICKETS Reaction of periosteum may occur
Indistinct cortex
Coarse trabeculation
Knees + wrists + ankles mainly affected
Epiphyseal plates widened + irregular
Tremendous metaphysis (fraying, splaying, cupping)
Spur (metaphyseal)
Cx: | stress fracture, bowing deformity |
Causes of Rickets
ABNORMALITY IN VITAMIN D METABOLISM associated with reactive hyperparathyroidism
Vitamin D deficiency (most common cause)
Dietary lack of vitamin D = famine osteomalacia = nutritional lack of vitamin precursors (vegetarian diet, prolonged total breast feeding without vitamin D supplementation)
Lack of sunshine exposure
eg, residence in high latitudes, clothing covering skin, sunshine avoidance for religious / cultural reasons, heavy skin pigmentation
Malabsorption of vitamin D
= gastroenterogenous rickets due to
Pancreatitis + biliary tract disease
Steatorrhea, celiac disease, postgastrectomy
Inflammatory bowel disease
Defective conversion of vitamin D to 25-OH-cholecalciferol (vitamin D3) in liver
Liver disease
Anticonvulsant drug therapy (= induction of hepatic enzymes that accelerate degradation of biologically active vitamin D metabolites)
Defective conversion of 25-OH-D3 to 1,25-OH-D3 in kidney
Chronic renal failure = renal osteodystrophy
Vitamin D dependent rickets = autosomal recessive enzyme defect of 1-OHase
ABNORMALITY IN PHOSPHATE METABOLISM
not associated with hyperparathyroidism secondary to normal serum calcium
P.157
Phosphate deficiency
Intestinal malabsorption of phosphates
Ingestion of aluminum salts [Al(OH)2] forming insoluble complexes with phosphate
Low phosphate feeding in prematurely born infants
Severe malabsorption state
Parenteral hyperalimentation
Disorders of renal tubular reabsorption of phosphate
Renal tubular acidosis (renal loss of alkali)
deToni-Debr -Fanconi syndrome = hypophosphatemia, glucosuria, aminoaciduria
Vitamin D resistant rickets
Cystinosis
Tyrosinosis
Lowe syndrome
Ifosfamide nephrotoxicity (for the treatment of rhabdomyosarcoma, Wilms tumor)
Hypophosphatemia with nonendocrine tumors
= Oncogenic rickets = elaboration of humeral substance which inhibits tubular reabsorption of phosphates (paraneoplastic phenomenon)
Nonossifying fibroma
Sclerosing hemangioma
Hemangiopericytoma
Ossifying mesenchymal tumor
Hypophosphatasia
CALCIUM DEFICIENCY
Dietary rickets = milk-free diet (extremely rare)
Malabsorption
Consumption of substances forming chelates with calcium
Classification of Rickets
Primary vitamin D deficiency rickets
Gastrointestinal malabsorption
Partial gastrectomy
Small intestinal disease: gluten-sensitive enteropathy / regional enteritis
Hepatobiliary disease: biliary atresia / chronic biliary obstruction / biliary cirrhosis resulting in failure of the emulsifying action of bile salts (fat-soluble vitamin) or failure of conversion
Pancreatic disease: chronic pancreatitis
Primary hypophosphatemia; vitamin D deficiency rickets
Renal disease
Chronic renal failure
Renal tubular disorders: renal tubular acidosis
Multiple renal defects
Hypophosphatasia + pseudohypophosphatasia
Fibrogenesis imperfecta osseum
Axial osteomalacia
Miscellaneous:
Hypoparathyroidism, hyperparathyroidism, thyrotoxicosis, osteoporosis, Paget disease, fluoride ingestion, ureterosigmoidostomy, neurofibromatosis, osteopetrosis, macroglobulinemia, malignancy
Rotator Cuff Lesions
Subacromial Pain Syndrome
Impingement syndrome
Rotator cuff tendinitis
Degeneration without impingement
Shoulder instability with secondary impingement
Instability without impingement
Impingement Syndrome
= clinical diagnosis consisting of lateral shoulder pain with abduction and forward flexion; NOT radiographic diagnosis
Cause: inadequate space for the normal motion of rotator cuff Age: lifelong process; 1st stage <25 years; 2nd stage 25 40 years; complete rotator cuff tear >40 years Pathophysiology:
movement of humerus impinges rotator cuff tendons against coracoacromial arch resulting in microtrauma, which causes inflammation of subacromial bursa
(= fibrous thickening of subacromial bursa) / rotator cuff (critical zone of rotator cuff = supraspinatus tendon 2 cm from its attachment to humerus)
Impingement pathophysiology may be secondary to primary instability!
Impingement anatomy:
narrowing of subacromial space secondary to
(1) acquired
degenerative subacromial osteophyte / enthesophyte from
bony outgrowth along coracoacromial ligament (= subacromial spur)
acromioclavicular joint hypertrophy in osteoarthrosis
hypertrophy of coracoacromial ligament
primary bursitis in rheumatoid arthritis
swollen supraspinatus tendon calcific tendinosis impinging upon coracoacromial arch
congenital
subacromial hook of anterior acromion (= subacromial spur)
increased curvature of acromion
os acromiale
Impingement syndrome may exist without impingement anatomy! painful arc of motion
night pain
X-ray (supraspinatus outlet + caudal tilt view):
anterior tilt / low position of acromion anterior subacromial spur (= enthesophyte) at insertion site of coracoacromial ligament
MR (can identify the anatomy predisposing to impingement):
unstable os acriomale pulled downward by deltoid muscle during abduction thickening of coracoacromial ligament acromioclavicular joint osteoarthritis bone spurs
US:
bunching of subdeltoid bursa during abduction of arm US can direct steroid injection into bursa
P.158
Cx: | (1) partial / complete tear (may be precipitated by acute traumatic event on preexisting degenerative changes; common cause of rotator cuff tears) |
(2) cuff tendinitis / degenerative tendinosis | |
Dx: | Lidocaine impingement test (= subacromial lidocaine injection relieves pain) |
Rx: | acromioplasty (= removal of a portion of the acromion), removal of subacromial osteophytes, removal / lysis / d bridement of coracoacromial ligament, resection of distal clavicle, removal of acromioclavicular joint osteophytes |
Glenohumeral Instability
Glenohumeral stability is dependent on a functional anatomic unit (= anterior capsular mechanism) formed by: glenoid labrum, joint capsule, superior + middle + anteroinferior + posteroinferior glenohumeral ligaments, coracohumeral ligament, subscapularis tendon, rotator cuff
Age: <35 years Frequency: acute, recurrent, fixed Cause: traumatic, microtraumatic, atraumatic Direction: anterior > multidirectional > inferior > posterior Type of lesions:
labral abnormalities (compression, avulsion, shearing), capsular / ligamentous tear / avulsion
Associated lesions:
Hill-Sachs fracture, trough line fracture, glenoid fracture, labral cyst
Normal clefts may exist within labrum!
False positive for labral separation:
Articular cartilage deep to labrum
Glenohumeral ligaments passing adjacent to labrum
Rotator Cuff Tear
Etiology:
Attritional change + tendon degeneration due to aging, repeated microtrauma as a result of impingement between humeral head + coracoacromial arch, overuse of shoulder from professional / athletic activities
Acute trauma (rare)
Age: most commonly >50 years; young athletic patient may have rim-rent tear (= avulsion of attachment at greater tuberosity Location: critical zone of anterior supraspinatus tendon 1 cm medial to tendon attachment (area of relative hypovascularity) Classification:
EXTENT OF TEAR
incomplete rupture = partial tear involves either bursal or synovial surface or remains intratendinous
fluid-filled defect not extending across the entire tendon width disruption of the superior / inferior tendon fibers only
complete rupture = full-thickness tear bridging subacromial bursa and glenohumeral joint
pure transverse tear
pure vertical / longitudinal tear
tear with retraction of tendon edges
global tear = massive tear / avulsion of cuff involving more than one of the tendons
TOPOGRAPHY OF TEAR
extent in frontal plane: nondisplaced, minimally displaced, dramatically displaced
extent in anterior direction: supraspinatus tendon + coracohumeral ligament + subscapularis tendon
extent in posterior direction: supraspinatus tendon + infraspinatus tendon + teres minor tendon
Assessment:
Size of tear
Amount of myotendinous retracion
Amount of surrounding tendinopathy
Muscle atrophy (decreased bulk, fatty infiltration) as strongest prognosticator of surgical outcome
Infraspinatus muscle atrophy is irreversible!
X-ray (late findings):
superior migration of humeral head remodeling of acromial undersurface Osseous changes in greater tuberosity do not correlate with cuff disease!
Arthrography (71 100% sensitive, 71 100% specific for combined full + partial thickness tears):
opacification of subacromial-subdeltoid bursa contrast enters substance of rotator cuff tendons
MR (41 100% sensitive and 79 100% specific for combined full + partial thickness tears):
discontinuity of cuff with retraction of musculotendinous junction focal / generalized intense / markedly increased signal intensity on T2WI (= fluid within cuff defect) in <50% fluid within subacromial-subdeltoid bursa (MOST SENSITIVE) low / moderate signal intensity on T2WI (= severely degenerated tendon, intact bursal / synovial surface, granulation / scar tissue filling the region of torn tendinous fibers) cuff defect with contour irregularity abrupt change in the signal character at boundary of the lesion supraspinatus muscle atrophy (MOST SPECIFIC) Pitfalls:
hyperintense focus in distal supraspinatus tendon gray signal isointense to muscle on all pulse sequences partial volume averaging with superior + lateral infraspinatus tendon
vascular watershed area
magic angle effect = orientation of collagen fibers at 55 relative to main magnetic field
hyperintense focus within rotator cuff on T2WI partial volume averaging with fluid in biceps tendon sheath / subscapularis bursa
partial volume averaging with fat of peribursal fat
motion artifacts: respiration, vascular pulsation, patient movement
fatty atrophy of muscle impingement of axillary / suprascapular nn. = quadrilateral space syndrome
DDx: (1) Partial-thickness tear with diffuse less-than-fluid intensity on T2WI (2) Tendon degeneration (tendonopathy) (3) Tendinitis (4) Full-thickness tear containing granulation tissue
US (scans in hyperextended position, 75 100% sensitive, 43 97% specific, 65 95% negative predictive value, 55 75% positive predictive value):
nonvisualization of rotator cuff (large tear), most reliable sign: deltoid muscle directly on top of humeral head defect filled with hypoechoic thickened bursa + fat (with hypervascularity on color Doppler) between deltoid and humeral head
focal nonvisualization of rotator cuff, reliable sign: naked tuberosity sign = retracted tendon leaves a bare area of bone folding of bursal + peribursal fat tissue into focal defect
discontinuity of rotator cuff filled with joint fluid / hypoechoic reactive tissue abrupt + sharply demarcated focal thinning small comma-shaped area of hyperechogenicity (small tear filled with granulation tissue / hypertrophied synovium)
P.159
False negative: | longitudinal tear, partial tear |
False positive: | intraarticular biceps tendon, soft-tissue calcification, small scar / fibrous tissue |
Subacromial-Subdeltoid Bursitis
common finding in rotator cuff tears
peribursal fat totally / partially obliterated + replaced by low-signal-intensity tissue on all pulse sequences fluid accumulation within bursa
Supraspinatus Tendinopathy / Tendinosis
= chronic tendon degeneration with disorganized repair
Cause: impingement, acute / chronic stress Histo: mucinous + myxoid degeneration increase in signal intensity in tendon on proton-density images without disruption of tendon tendinous enlargement + inhomogeneous signal pattern fibers on superior + inferior tendon surface remain visible and contiguous
Cx: | main risk factor for subsequent rotator cuff tear (not impingement) |
DDx: | supraspinatus tear (tendon has fluid intensity |
Rubella
= CONGENITAL RUBELLA = GERMAN MEASLES
Incidence: endemic rate of 0.1% Age: infants (in utero transmission) neonatal dwarfism (intrauterine growth retardation) failure to thrive
retinopathy, cataracts, glaucoma, microphthalmia
deafness
mental deficiency with encephalitis + microcephaly
thrombocytopenic purpura, petechiae, anemia
celery-stalk sign (50%) = metaphyseal irregular margins + coarsened trabeculae extending longitudinally from epiphysis; distal end of femur > proximal end of tibia, humerus no periosteal reaction hepatosplenomegaly + adenopathy pneumonitis @ Cardiovascular:
congenital heart disease (PDA, VSD) peripheral pulmonary artery stenosis necrosis of myocardium
@ CNS
punctate / nodular calcifications porencephalic cysts occasionally microcephaly
Prognosis: | osseous manifestations disappear in 1 3 months; severe congenital defects from infection during first trimester |
DDx: | (1) CMV |
(2) Congenital syphilis (diaphysitis + epiphysitis) | |
(3) Toxoplasmosis |
Rubinstein-Taybi Syndrome
= BROAD THUMB SYNDROME
= rare sporadic syndrome without known chromosomal / biochemical markers; M:F = 1:1
small stature
mental, motor, language retardation
@ Characteristic facies
beaked / straight nose low nasal septum
antimongoloid slant of palpebral fissures
epicanthic folds
broad fleshy nasal bridge
high-arched palate
dental abnormalities
@ Ophthalmologic findings
strabismus, ptosis, refractive errors
@ Cutaneous findings
keloids, hirsutism, simian crease
flat capillary hemangioma on forehead / neck
@ Musculoskeletal findings
short broad spatulate terminal phalanges of thumb and great toe angulation deformity (MOST CONSISTENT + CHARACTERISTIC FINDING) radial angulation of distal phalanx (50%) caused by trapezoid / delta shape of proximal phalanx tufted mushroom-shaped fingers + webbing thin tubular bones of hand + feet club feet skeletal maturation retardation dysplastic ribs spina bifida occulta scoliosis flat acetabular angle + flaring of ilia
@ Genitourinary tract anomalies
bilateral renal duplication renal agenesis bifid ureter incomplete / delayed descent of testes
@ Cardiovascular abnormalities
atrial septal defect patent ductus arteriosus coarctation of aorta valvular aortic stenosis pulmonic stenosis
P.160
OB-US:
decreased head circumference small for gestational age
Cx in infancy: | obstipation, feeding problems, recurrent upper respiratory infection |
Sapho Syndrome
= Synovitis, Acne, Palmoplantar pustulosis, Hyperostosis, Osteitis
= PUSTULOTIC ARTHROSTEITIS = STERNOCLAVICULAR HYPEROSTOSIS
= association between rheumatologic and cutaneous lesions (= seronegative spondyloarthropathy)
Delay of several years can separate osseous from cutaneous lesions! Etiology: ? variant of psoriasis Age: young to middle-aged adults; M:F = 1:1 palmoplantar pustulosis (52%) = chronic eruption of yellowish intradermal sterile pustules on palms + soles
severe acne (15%) = acne fulminans, acne conglobata
pain, soft-tissue swelling, limitation of motion at skeletal site of involvement
@ Sternoclavicular joint (70 90%)
Site: insertion of costoclavicular ligament, clavicles, manubrium sterni osteolysis at beginning of disease hyperostosis + osteosclerosis arthritis + ankylosis of sternoclavicular joint
@ Axial skeleton (33%)
osteosclerosis of one / more vertebral bodies disk space narrowing + endplate erosion paravertebral ossifications (mimicking marginal / nonmarginal syndesmophytes / massive bridging) unilateral sacroiliitis + associated osteosclerosis of adjacent iliac bone
@ Appendicular skeleton (30%)
Location: distal femur, proximal tibia, fibula, humerus, radius, ulna Site: metaphysis osteosclerosis / osteolysis + periosteal new bone formation with aggressive appearance
@ Joints
Location: knee, hip, ankle, DIP of hand synovial inflammation with juxtaarticular osteoporosis (early) joint narrowing, marginal erosion, hyperostosis, enthesopathy (later)
Prognosis: | chronic course with unpredictable exacerbations + remissions |
Rx: | nonsteroidal antiinflammatory drugs, corticosteroids, analgesics, cyclosporine |
DDx: | infectious osteomyelitis / spondylitis, osteosarcoma, Ewing sarcoma, metastasis, Paget disease, aseptic necrosis of clavicle |
Sarcoidosis
Osseous involvement in 6 15 20%
unimpaired joint function, joints are rarely involved
Location: small bones of hands + feet (middle + distal phalanges) reticulated lacelike trabecular pattern in metaphyseal ends of middle + distal phalanges, metacarpals, metatarsals well-defined cystlike lesions of varying size neuropathy-like destruction of terminal phalanges (DDx: scleroderma) phalangeal endosteal sclerosis + periosteal new bone (infrequent) vertebral involvement unusual: destructive lesions with sclerotic margin diffuse sclerosis of multiple vertebral bodies paravertebral soft-tissue mass (DDx: indistinguishable from tuberculosis) osteolytic changes in skull
Scurvy
= BARLOW DISEASE = HYPOVITAMNOSIS C
= vitamin C (= ascorbic acid) deficiency with defective osteogenesis from abnormal osteoblast function
Infantile Scurvy
Age: | 6 9 months (maternal vitamin C protects for first 6 months) |
Predisposed: | feeding with pasteurized / boiled milk |
Pathogenesis: | abnormal collagen formation |
irritability
tenderness + weakness of lower limbs
scorbutic rosary of ribs
bleeding of gums (teething)
legs drawn up + widely spread = pseudoparalysis
Location: distal femur (esp. medial side), proximal and distal tibia + fibula, distal radius + ulna, proximal humerus, sternal end of ribs ground-glass osteoporosis (CHARACTERISTIC) cortical thinning soft-tissue edema (rare) @ Metaphysis
white line of Fr nkel = metaphyseal zone of preparatory calcification (DDx: lead / phosphorus poisoning, bismuth treatment, healing rickets) Tr mmerfeld zone = radiolucent zone on shaft side of Fr nkel's white line (site of subepiphyseal infraction) Pelkan spurs = metaphyseal spurs projecting at right angles to shaft axis Parke corner sign = subepiphyseal infraction / comminution resulting in mushrooming / cupping of epiphysis (DDx: syphilis, rickets)
@ Epiphysis
Wimberger ring = sclerotic ring around low-density epiphysis (due to osteopenia of epiphysis)
@ Diaphysis
subperiosteal hematoma with calcification of elevated periosteum (sure sign of healing)
@ Teeth
cyst formation + hemorrhage in enamel
DDx: | TORCH infections, leukemia, neuroblastoma |
Adult Scurvy
Incidence: | rare |
P.161
hemarthroses + bleeding at synchondroses
Septic Arthritis
N.B.: | MEDICAL EMERGENCY = immediate treatment necessary to prevent permanent joint damage! |
Organism:
most often due to Staphylococcus aureus;
gonorrhea (multifocal septic arthritis in young adults; indistinguishable from tuberculous arthritis, but more rapid);
brucellar arthritis (indistinguishable from tuberculosis, slow infection);
Salmonella (commonly associated with sickle cell disease / Gaucher disease)
(a) neonates, infants: group D streptococcus (b) <4 years of age: Hemophilus influenzae, Strepto-coccus pyogenes, S. aureus (c) >4 years of age: S. aureus (d) >10 years of age: S. aureus, Neisseria gonorrheae (e) adults: S. aureus
Pathophysiology:
lytic enzymes in purulent articular fluid destroy articular + epiphyseal cartilages
pus increases intraarticular pressure and compromises blood flow to epiphysis resulting in osteonecrosis
Mode of infection:
hematogenous spread (most common; IV drug abuser, immunocompromised patient):
hip, knee in children
the five S joints in adults:
Shoulder (AC joint)
Sternoclavicular joint
Spine
SI joint
Symphysis pubis
contiguous spread from focus of osteomyelitis
metaphyseal focus: hip, elbow, shoulder, ankle have intraarticular metaphyses (children)
epiphyseal focus: growth plate perforated by vascular channels in children <1 year of age
direct inoculation of joint from penetrating wound:
small joints of hand + feet; unusual organisms like Pseudomonas + Klebsiella
Age: | most prevalent in the young |
Location: | lower extremity (75%) with hip + knee in 90% |
pain, limp, pseudoparalysis
warmth, swelling
septic clinical picture
bacteremia, leukocytosis
ACUTE SIGNS:
initial radiographs frequently normal soft-tissue swelling (first sign secondary to local hyperemia + edema) joint distension (effusion) subluxation of hip and humerus in children (early) joint space narrowing = rapid development of destruction of articular cartilage (not in tuberculous arthritis) rapid periarticular osteoporosis
US:
detection + follow-up of hip effusion
NUC:
increased activity in joint + adjacent osteomyelitis occasionally decreased activity simulating avascular necrosis (2 to joint effusion, vascular spasm, vascular compression)
MR:
hypointense signal in bone marrow on T1WI enhancement of abnormal bone marrow on fat-suppressed T1WI hyperintense signal in bone marrow on fat-suppressed T2WI
SUBACUTE SIGNS after 8 10 days:
small marginal + central erosions in articular cortex / loss of entire cortical outline (marginal erosions in tuberculosis) reactive bone sclerosis in underlying bone subchondral bone destruction (by synovial proliferation) defective reparation / ankylosis (if entire cartilage is destroyed) local bone atrophy (immobility) metaphyseal bone destruction (if osteomyelitis is source of septic joint)
Dx: | (1) prompt arthrocentesis: turbid / frankly purulent synovial fluid: fluid WBC >20,000/mm3 with predominance of PMNs: positive result of Gram stain (2) blood culture |
Cx: | (1) bone growth disturbance (lengthening, shortening, angulation) (2) chronic degenerative arthritis (3) ankylosis (4) osteonecrosis = avascular necrosis |
Shin Splints
= SHIN SORENESS = MEDIAL TIBIAL STRESS SYNDROME
= SOLEUS SYNDROME
= nonspecific term describing exertional lower leg pain
Incidence: 75% of exertional leg pain Cause: ? atypical stress fracture, traction periostitis, compartment syndrome diffuse tenderness along posteromedial tibia in its middle to distal aspect Location: posterior / posteromedial tibial cortex Plain radiographs:
normal / longitudinal periosteal new bone
Bone scintigraphy:
normal radionuclide angiogram + blood-pool phase (DDx to stress fracture) linear longitudinal uptake on delayed images
MR:
marrow edema / hemorrhage periosteal fluid
Short Rib Polydactyly Syndrome
= group of autosomal recessive disorders characterized by short limb dysplasia, constricted thorax, postaxial polydactyly (on ulnar / fibular side)
P.162
TYPE I = SALDINO-NOONAN SYNDROME TYPE II = MAJEWSKI TYPE TYPE III = NAUMOFF TYPE TYPE IV = BEEMER severe micromelia pointed femurs at both ends (type I); widened metaphyses (type III) narrow thorax extremely short horizontally oriented ribs distorted underossified vertebral bodies + incomplete coronal clefts polydactyly cleft lip / palate Prognosis: uniformly lethal
Sickle cell disease
Abnormal hemoglobins:
HbS = DNA mutation substituting glutamic acid in position 6 on -chain with valine HbC = DNA mutation substituting glutamic acid in position 6 on -chain with lysine homozygous = HbSS = sickle cell anemia
heterozygous = HbSA = sickling trait but no anemia
heterozygous variants:
HbSC (less severe form)
HbS -thalassemia anemia (seen occasionally)
Incidence: 8 13% of American Blacks carry sickling factor (HbS); 1:40 with sickle cell trait will manifest sickle cell anemia (HbSS); 1:120 with sickle cell trait will manifest HbSC disease Pathogenesis:
altered shape + plasticity of RBCs under lowered oxygen tension lead to increased blood viscosity, stasis, log jam occlusion of small blood vessels, infarction, necrosis, superinfection; damage of intima occurs most frequently in vessels with high flow rates (terminal ICA);
sickling occurs in areas of
slow flow (spleen, liver, renal medulla)
rapid metabolism (brain, muscle, fetal placenta)
chronic hemolytic anemia (increased sequestration of sickled RBCs in spleen), jaundice
chronic leg ulcers, priapism
abdominal crisis
rheumatism-like joint pain
skeletal pain (osteomyelitis, cellulitis, bone marrow infarction)
splenomegaly (in children + infants), later organ atrophy
Cx: high incidence of infections (lung, bone, brain) Prognosis: death <40 years (1) DEOSSIFICATION DUE TO MARROW HYPERPLASIA
porous decrease in bone density of skull (25%) widening of diploe with decrease in width of outer table (22%) vertical hair-on-end striations (5%) osteoporosis with thinning of trabeculae biconcave fish vertebrae (bone softening) in 70% widening of medullary space + thinning of cortices coarsening of trabecular pattern in long + flat bones rib notching pathologic fractures
(2) THROMBOSIS AND INFARCTION
Location: in diaphysis of small tubular bones (children); in metaphysis + subchondrium of long bones (adults) osteolysis (in ACUTE infarction) dystrophic medullary calcification periosteal reaction (bone-within-bone appearance) juxtacortical sclerosis Lincoln log = Reynold sign = H-vertebrae = steplike endplate depression articular disintegration collapse of femoral head (DDx: Perthes with involvement of metaphysis)
MR:
diffusely decreased signal of marrow on short + long TR/TE images (= hematopoietic marrow replacing fatty marrow) focal areas of decreased signal intensity on short TR/TE + increased intensity on long TR/TE (= acute marrow infarction) focal areas of decreased signal intensity on short TR/TE + long TR/TE images (= old infarction / fibrosis)
(3) SECONDARY OSTEOMYELITIS
Organism: Salmonella in unusual frequency, also Staphylococcus periostitis (DDx: indistinguishable from bone infarction) dactylitis = hand-foot syndrome
(4) GROWTH EFFECTS (secondary to diminished blood supply)
Location: particularly in metacarpal / phalanx bone shortening = premature epiphyseal fusion epiphyseal deformity with cupped metaphysis cup / peg-in-hole defect of distal femur diminution in vertebral height (shortening of stature + kyphoscoliosis)
@ Brain
Pathophysiology:
chronic anemia produces cerebral hyperemia, hypervolemia, impaired autoregulation
(a) cerebral blood flow cannot be increased leading to infarction in time of crisis
(b) increased cerebral blood flow produces epithelial hyperplasia of large intracranial vessels (terminal ICA / proximal MCA) resulting in thrombus formation
stroke (5 17%): ischemic infarction (70%), ischemia of deep white matter (25%), hemorrhage (20%), embolic infarction
Angio (in 87% abnormal):
arterial stenosis / occlusion of supraclinoid portion of ICA + proximal segments of ACA and MCA moyamoya syndrome (35%) distal branch occlusion (secondary to thrombosis / embolism) aneurysm (rare)
CT:
cerebral infarction (mean age of 7.7 years)
subarachnoid hemorrhage (mean age of 27 years)
@ Chest
cardiomegaly + CHF
@ Gallbladder
cholelithiasis
@ Kidney
hematuria
hyposthenuria
nephrotic syndrome
renal tubular acidosis (distal)
hyperuricemia
progressive renal insufficiency
normal urogram (70%) papillary necrosis (20%) focal renal scarring (20%) smooth large kidney (4%) MR:
decreased cortical signal on T2-weighted images (renal cortical iron deposition)
@ Spleen
splenomegaly < age 10 (in patients with heterozygous sickle cell disease) Cx: splenic rupture splenic infarction hemosiderosis
Bone marrow scintigraphy:
usually symmetric marked expansion of hematopoietic marrow beyond age 20 involving entire femur, calvarium, small bones of hand + feet (normally only in axial skeleton + proximal femur and humerus) bone marrow defects indicative of acute / old infarction
Tc-99m diphosphonate scan:
increased overall skeletal uptake (high bone-to-soft tissue ratio) prominent activities at knees, ankles, proximal humerus (delayed epiphyseal closure / increased blood flow to bone marrow) bone marrow expansion (calvarial thickening with relative decrease in activity along falx insertion) decreased / normal uptake on bone scan within 24 hours in acute infarction / posthealing phase following infarction (cyst formation) increased uptake on bone scan after 2 10 days persistent for several weeks in healing infarction increased uptake on bone scan within 24 48 hours in osteomyelitis increased blood-pool activity + normal delayed image on bone scan in cellulitis renal enlargement with marked retention of tracer in renal parenchyma (medullary ischemia + failure of countercurrent system) in 50% persistent splenic uptake (secondary to degeneration, atrophy, fibrosis, calcifications)
P.163
Functional Asplenia
= anatomically present nonfunctional spleen
Howell-Jolly bodies, siderocytes, anisocytosis, irreversibly sickled cells
normal-sized / enlarged spleen on CT absence of tracer uptake on sulfur colloid scan
Autosplenectomy
= autoinfarction of spleen in homozygous sickle cell disease (function lost by age 5)
Histo: extensive perivascular fibrosis with deposition of hemosiderin + calcium small (as small as 5 10 mm) densely calcified spleen
Acute Splenic Sequestration Crisis
= sudden trapping of large amount of blood in spleen
Cause: obstruction of small intrasplenic veins / sinusoids; unknown trigger event Age: (a) homozygous: infancy / childhood (b) heterozygous: any age
LUQ pain
sudden massive splenic enlargement
rapid drop in hemoglobin, hematocrit, platelets (spleen traps large volumes of blood)
rise in reticulocytes
enlarged spleen multiple lesions at periphery of spleen: hypoechoic by US, of low attenuation by CT hyperdense areas (due to acute hemorrhage) hyperintense areas on T1WI + T2WI (due to subacute hemorrhage) main splenic vessels patent by Doppler US Prognosis: in 50% death <2 years of age (due to hypovolemic shock)
Sickle Cell Trait
Hb SA carrier; mild disease with few episodes of crisis + infection; sickling provoked only under extreme stress (unpressurized aircraft, anoxia with CHD, prolonged anesthesia, marathon running)
Incidence: in 8 10% of American Blacks may have normal blood count
recurrent gross hematuria
splenic infarction
SC Disease
Hb SC carrier
Incidence: 3% of American Blacks retinal hemorrhages
hematuria due to multiple infarctions
aseptic necrosis of hip
Sickle-Thal Disease
Resembling clinically Hb SS patients
anemia (no normal adult hemoglobin)
persistent splenomegaly
Sinding-Larsen-Johansson Disease
= osteochondrosis of inferior pole of patella, often bilateral (NOT osteonecrosis / epiphysitis / osteochondritis)
Cause: traction with contusion + subsequent tendinitis / traumatic avulsion of bone; repeated subluxation dislocation of patella Age: adolescents (often 10 14 years) Predisposed: cerebrospastic children tenderness + soft-tissue swelling over lower pole of patella peripatellar soft-tissue swelling calcification / ossification of patellar tendon small bone fragments at lower pole of patella (LAT view) MR:
hypointense area on T1WI + hyperintense on T2WI in inferior pole of patella + surrounding soft tissues
P.164
Smallpox
5% of infants
Location: elbow bilateral; metaphysis of long bones rapid bone destruction spreading along shaft periosteal reaction endosteal + cortical sclerosis frequent premature epiphyseal fusion with severe deformity ankylosis is frequent
Soft-Tissue Chondroma
= EXTRASKELETAL CHONDROMA = CHONDROMA OF SOFT PARTS
Incidence: 1.5% of all benign soft-tissue tumors Age: 30 60 years (range 1 85 years); M:F = 1.2:1 Histo: adult-type hyaline cartilage with areas of calcification + ossification; myxoid change; regions of increased cellularity + cytologic atypia slow-growing soft-tissue mass
occasionally pain + tenderness
Location: hand (54 64%) + foot (20 28%) lobulated well-defined extraskeletal mass <2 cm in size may contain calcifications (33 70%) with ringlike appearance / ossifications scalloping of adjacent bone with sclerotic reaction MR:
high signal intensity on T2WI intermediate signal intensity on T1WI
Rx: local excision Prognosis: 15 25% recurrence rate DDx: (1) Extraskeletal myxoid chondrosarcoma (deep-seated in large muscles of upper + lower extremities, pelvic + shoulder girdles) (2) Periosteal chondroma
Soft-Tissue Osteoma
= OSTEOMA OF SOFT PARTS (extremely rare)
Histo: mature lamellar bone with well-defined haversian system; bone marrow, myxoid, vascular, fibrous connective tissue between bone trabeculae; collagenous capsule blending into benign hyaline cartilage Location: head (usually posterior part of tongue), thigh ossified mass NUC:
intense tracer accumulation, greater than adjacent bone
Solitary Bone Cyst
= UNICAMERAL / SIMPLE BONE CYST
Incidence: up to 5% of primary bone lesions Etiology: ? trauma (synovial entrapment at capsular reflection),? vascular anomaly (blockage of interstitial drainage) Histo: cyst filled with clear yellowish fluid often under pressure, wall lined with fibrous tissue + hemosiderin, giant cells may be present Age: 3 19 years (80%); occurs during active phase of bone growth; M:F = 3:1 asymptomatic, unless fractured Location: proximal femur + proximal humerus (60 75%), fibula, at base of calcaneal neck (4%, >12 years of age), talus; rare in ribs, ilium, small bones of hand + feet (rare), NOT in spine / calvarium; solitary lesion Site: intramedullary centric metaphyseal, adjacent to epiphyseal cartilage (during active phase) / migrating into diaphysis with growth (during latent phase), does not cross epiphyseal plate 2 3 cm oval radiolucency with long axis parallel to long axis of host bone fine sclerotic boundary scalloping + erosion of internal aspect of underlying cortex photopenic area on bone scan (if not fractured) fallen fragment sign if fractured (20%) = centrally dislodged fragment falls into a dependent position Prognosis: mostly spontaneous regression Cx: pathologic fracture (65%) DDx: (1) Enchondroma (calcific stipplings) (2) Fibrous dysplasia (more irregular lucency)
(3) Eosinophilic granuloma
(4) Chondroblastoma (epiphyseal)
(5) Chondromyxoid fibroma (more eccentric + expansile)
(6) Giant cell tumor
(7) Aneurysmal bone cyst (eccentric)
(8) Hemorrhagic cyst
(9) Brown tumor
Solitary Plasmacytoma of Bone
= represents early stage of multiple myeloma, precedes multiple myeloma by 1 20 years
Age: 5th 7th decade negative marrow aspiration; no IgG spike in serum / urine A. SOLITARY MYELOMA OF BONE
Site: thoracic / lumbar spine (most common) > pelvis > ribs > sternum, skull, femora, humeri solitary bubbly osteolytic grossly expansile lesion poorly defined margins, Swiss-cheese pattern frequently pathologic fracture (collapse of vertebra) DDx: giant cell tumor, aneurysmal bone cyst, osteoblastoma, solitary metastasis from renal cell / thyroid carcinoma
B. EXTRAMEDULLARY PLASMACYTOMA
Location: majority in head + neck; 80% in nasal cavity, paranasal sinuses, upper airways of trachea, lung parenchyma
Spondyloepiphyseal Dysplasia
Spondyloepiphyseal Dysplasia Congenita
Autosomal dominant / sporadic (most)
disproportionate dwarfism with spine + hips more involved than extremities
waddling gait + muscular weakness
flat facies
short neck
deafness
cleft palate @ Axial skeleton
ovoid vertebral bodies + severe platyspondyly (incomplete fusion of ossification centers + flattening of vertebral bodies) hypoplasia of odontoid process (Cx: cervical myelopathy) progressive kyphoscoliosis (short trunk) involving thoracic + lumbar spine narrowing of disk spaces (resulting in short trunk) broad iliac bases + deficient ossification of pubis flat acetabular roof
@ Chest
bell-shaped thorax pectus carinatum
@ Extremities
normal / slightly shortened limbs severe coxa vara + genu valgum multiple accessory epiphyses in hands + feet talipes equinovarus Cx: (1) Retinal detachment, myopia (50%) (2) Secondary arthritis in weight-bearing joints
P.165
Spondyloepiphyseal Dysplasia Tarda
= sex-linked recessive form with milder manifestation + later clinical onset
Age: apparent by 10 years; exclusive to males hyperostotic new bone along posterior 2/3 of vertebral end plate (PATHOGNOMONIC) platyspondyly with depression of anterior 1/3 of vertebral body narrowing with calcification of disk spaces + spondylitic bridging short trunk dysplastic joints (eg, flattened femoral heads) premature osteoarthritis DDx: Ochronosis
Sprengel Deformity
= failure of descent of scapula secondary to fibrous / osseous omovertebral connection
Associated with: Klippel-Feil syndrome, renal anomalies webbed neck shoulder immobility
elevation + medial rotation of scapula
Subungual Exostosis
= DUPUYTREN EXOSTOSIS
Cause: repetitive trauma (14 25%) Age: 2nd 3rd decade (range, 7 58 years) Histo: proliferating fibroblasts developing into fibrocartilage + bone Location: toes (86 90%, great toe in 77 80%), thumb + index finger (10 14%, dominant hand in 75%) Site: dorsal / dorsomedial aspect of distal phalanx mass under / adjacent to nail bed rapid growth
may be painful with overlying skin ulceration
ossific mass distal to physeal scar: NO continuity to cortex / medulla of host bone broad / narrow base indistinct / well-demarcated cartilage cap larger than base Rx: complete surgical excision Prognosis: 11 53% recurrence rate DDx: osteochondroma (exostosis continuous with cortex and medulla of host bone)
Superficial Fibromatoses
Infantile Digital Fibromatosis
= REYE TUMOR = INFANTILE DIGITAL FIBROMA = INFANTILE DIGITAL MYOFIBROBLASTOMA
= single / multiple nodular dermal protrusion of fibrous tissue on extensor surface of digits
Age: 1st year of life (>80%); 30% congenital Histo: intracytoplasmic perinuclear inclusion bodies Location: fingers (60%), toes (40%) Site: lateral aspect of distal / middle phalanx nonspecific soft-tissue mass involving a digit infrequently bone involvement Prognosis: spontaneous regression (in 8%); 60% recurrence rate after excision
Juvenile Aponeurotic Fibroma
= CALCIFIED APONEUROTIC FIBROMA
= rare locally aggressive benign fibrous tumor
Histo: cellular dense fibrous tissue with focal chondral elements infiltrating adjacent structures (= cartilaginous tumor) Age: children + adolescents (within first 2 decades of life); M:F = 2:1 slow-growing asymptomatic soft-tissue mass
Location: deep palmar fascia of hand + wrist (67%); soles of feet nonspecific soft-tissue mass overlying inflamed bursa (often mistaken for calcified bursitis) stippled calcifications (frequent) interosseous soft-tissue mass of forearm + wrist erosion / scalloping of bone may occur Prognosis: recurrence rate of >50% after resection Dx: biopsy (to differentiate from synovial sarcoma) DDx: synovial sarcoma (commonly calcifies, bone erosion), chondroma, fibrosarcoma, osteosarcoma, myositis ossificans
Palmar Fibromatosis
= DUPUYTREN DISEASE
Prevalence: 1 2% Age: in 24% of people >65 years; M:F = 4:1 subcutaneous nodules on palmar surface of distal crease of hand progressing to cords and bands
flexion contractures of digits (2 to fibrous attachment to flexor tendons)
Location: 4th + 5th (most commonly) > 2nd + 3rd digit; bilateral in 42 60% predominantly hypointense on T2WI + low to intermediate intensity on T1WI (in hypocellular lesions) intermediate signal intensity on T2WI (proliferative hypercellular lesions)
Plantar Fibromatosis
= PLANTAR FASCIITIS = LEDDERHOSE DISEASE
= common form of superficial fibromatosis
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Cause: trauma Age: 30 50 years Path: abnormal fibrous tissue replacing the plantar aponeurosis and infiltrating subcutaneous tissue + skin Histo: nonencapsulated proliferation of fibroblasts separated by variable amounts of collagen At risk: runners, obese patients Associated with (in 50%): Dupuytren contracture (10 65%), Peyronie disease heel pain (one of the most common causes)
one / multiple firm fixed subcutaneous nodules
Location: proximal / central portion of plantar aponeurosis; bilateral in 20 50% Site: medial aspect of aponeurosis calcaneal spur MR:
single or multiple nodules / poorly defined infiltrative mass iso- / hypointense compared to plantar muscles on T1WI + T2WI marked contrast enhancement in 50% subcutaneous edema
Synovial Osteochondromatosis
= SYNOVIAL CHONDROMATOSIS = JOINT CHONDROMA
Primary Synovial Osteochondromatosis
= benign self-limiting monoarticular disorder characterized by proliferation + metaplastic transformation of the synovium with formation of multiple intrasynovial cartilaginous / osteocartilaginous nodules
Cause: hyperplastic synovium with cartilage metaplasia (foci <2 3 cm); loose body may remain free floating / conglomerate with other loose bodies into large mass / reattach to synovium with either reabsorption or continued growth Histo: foci of hyaline cartilage with mineralized chondroid matrix beneath synovial surface + within subsynovial connective tissue; hypercellularity + nuclear atypia may be confused with malignancy Composition of cartilaginous bodies:
cartilage alone / cartilage + bone / mature bone + fatty marrow
Age: presents in 3rd 5th decade; M:F = 2 4:1 slow-growing soft-tissue mass in joint
progressive joint pain for several years with limitation of motion / locking
hemorrhagic joint effusion
Location: knee (most common with >50%, in 10% bilateral) elbow > hip > shoulder > ankle > wrist; usually monoarticular, occasionally bilateral Sites: joint / tendon sheath / ganglion / bursa / periarticular multiple calcified / ossified loose bodies in a single joint (bony shell of remodeled lamellar bone is rare) in a rings-and-arcs morphology size of nodules varies between a few mm to several cm varying degrees of bone mineralization (25 30% of chondromas show no radiopacity)
pressure erosion of adjacent bone in joints with tight capsule (eg, hip) widening of joint space (from accumulation of loose bodies) joint effusion uncommon NO osteoporosis CT:
multiple calcified / ossified intraarticular bodies intraarticular soft-tissue mass of near-water attenuation containing multiple small calcifications
MR:
lobulated intraarticular mass isointense to muscle on T1WI + hyperintense to muscle on T2WI containing multiple foci of low signal intensity DDx: large effusion, soft-tissue tumor peripheral contrast enhancement of chondral lesions central area of high-signal intensity on T1WI for intraarticular bodies with fatty marrow
Cx: (1) Long-standing disease may lead to degenerative arthritis (from chronic mechanical irritation + destruction of articular cartilage by loose bodies) (2) Malignant dedifferentiation to chondrosarcoma
Rx: removal of loose bodies (recurrence is common) DDx: (1) Synovial sarcoma, chondrosarcoma (2) Osteochondral fracture (history of trauma), osteochondritis dissecans, osteonecrosis
(3) Secondary osteochondromatosis
(4) Pigmented villonodular synovitis, synovial hemangioma, lipoma arborescens
Secondary Synovial Osteochondromatosis
= joint surface disintegration
Cause: trauma, osteonecrosis, rheumatoid arthritis, neuropathic arthropathy, tuberculous arthritis, degenerative joint disease intraarticular bodies tend to be larger, less numerous, more varied in size compared to primary synovial osteochondromatosis prominent osteoarthritis
Synovioma
= SYNOVIAL SARCOMA
= slow-growing expansile malignant tumor originating in the synovial lining / bursa / tendon sheath; uncommonly intraarticular
Incidence: 10% of soft-tissue sarcomas Histo: fibrosarcomatous (spindle cell) with areas of hyalinization + synovial (epithelial cell) component Age: 3rd 5th decade; M:F = 2:3 painful soft-tissue mass Location: lower extremity (2/3): knee (most common), hip, ankle; upper extremity (1/3): elbow, wrist, hands, feet; usually solitary large spheroid well-defined soft-tissue mass lesion about 1 cm removed from joint cartilage amorphous punctate calcifications / ossification (1/3), often at periphery of tumor Calcification in other soft-tissue connective tissue sarcomas is uncommon!
involvement of adjacent bone (11 20%): periosteal reaction bone remodeling (pressure from tumor) invasion of cortex with wide zone of transition
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juxtaarticular osteoporosis MR:
poorly defined + infiltrative low signal intensity on T1WI; high signal intensity on T1WI from hemorhage inhomogeneous tumor: hyperintense (cystic) + isointense (solid) + hypointense (fibrous) elements on T2WI multilocular appearance with internal septation fluid-fluid levels (previous hemorrhage)
Rx: local excision / amputation + radiation / chemotherapy
Syphilis of Bone
Congenital Syphilis
Transplacental transmission cannot occur <16 weeks gestational age positive rapid plasma reagin (measures quantity of antibodies to assess new infection / efficacy of Rx)
positive microhemagglutination test for Treponema pallidum (remains reactive for life)
pneumonia alba hepatomegaly Location: symmetrical bilateral osteomyelitis involving multiple bones (HALLMARK) A. Early phase
Skeletal radiography abnormal in 19% of infected newborns without overt disease! 1. Metaphysitis
lucent metaphyseal band adjacent to thin / widened zone of provisional calcification (disturbance in enchondral bone growth) frayed edge of metaphyseal-physeal junction (osteochondritis) = erosions + lytic defects
2. Diaphyseal periostitis = luetic diaphysitis
solid / lamellated periosteal new-bone growth = bone-within-bone appearance
3. Spontaneous epiphyseal fractures causing Parrot pseudopalsy (DDx: battered child syndrome)
4. Bone destruction
marginal destruction of spongiosa + cortex along side of shaft with widening of medullary canal (in short tubular bones) patchy rarefaction in diaphysis
5. Wimberger sign
symmetrical focal bone destruction of medial portion of proximal tibial metaphysis (ALMOST PATHOGNOMONIC)
B. Late phase
Hutchinson triad = dental abnormality, interstitial keratitis, 8th nerve deafness frontal bossing of Parrot = diffuse thickening of outer table saddle nose + high palate (syphilitic chondritis + rhinitis) short maxilla (maxillary osteitis) thickening at sternal end of clavicle saber-shin deformity = anteriorly convex bowing in upper 2/3 of tibia with bone thickening
Acquired Syphilis
= TERTIARY SYPHILIS resembles chronic osteomyelitis
dense bone sclerosis of long bones irregular periosteal proliferation + endosteal thickening with narrow medulla extensive calvarial bone proliferation with mottled pattern (anterior half + lateral skull) in outer table (DDx: fibrous dysplasia, Paget disease) ill-defined lytic destruction in skull, spine, long bones (gumma formation) enlargement of clavicle (cortical + endosteal new bone) Charcot arthropathy of lower extremities + spine
Tarsal Coalition
= abnormal fibrous / cartilaginous / osseous fusion of two or more tarsal ossification bones
Clinically most important congenital problem of calcaneus Prevalence: 1 2% of population Cause: abnormal segmentation of primitive mesenchyme with lack of joint formation Age: fibrous coalition at birth, ossification during 2nd decade of life with onset of symptoms; M:F = 1:1 asymptomatic; often first noted after antecedent trauma / weight gain / increase in athletic activity
peroneal spastic / rigid pes planus (=flatfoot) in adjustment for calcaneus valgus (= heel valgus)
hindfoot / tarsal pain or stiffness
both feet affected in 20 50% osseous bars between bones of hindfoot / bones in close proximity with irregular surfaces MR (of joint space):
bone marrow contiguity (osseous coalition) fluid- / cartilage-intensity (cartilaginous coalition) intermediate- to low-signal intensity (fibrous coalition) reactive periarticular bone changes bone marrow edema along fused joint (STIR images)
Types:
Calcaneonavicular coalition (45%)
Age: 8 12 years (due to earlier ossification) rigid flat foot pain in 2nd decade of life
Radiographs:
narrowed calcaneonavicular joint with indistinct articular margins (bones that usually do not articulate) widening / flattening of anteromedial calcaneus anteater's nose = elongation of anterior dorsal calcaneus on lateral radiograph hypoplastic talar head
CT (axial scan):
broadening of medial aspect of anterodorsal calcaneus in apposition to navicular narrowing of space between the 2 bones + minimal marginal reactive sclerosis
Dx: mostly diagnosed on 45 internal oblique films
Talocalcaneal coalition (45%)
Age: 12 16 years painful peroneal spastic flat foot, relieved by rest
Site: middle facet at level of sustentaculum tali (most frequently) Secondary radiographic signs (due to alteration in hindfoot biomechanics):
prominent talar beak (66%) arising from dorsal aspect of head / neck of talus (due to impaired subtalar joint motion) rounding of the lateral talar process narrowing of posterior subtalar joint lack of depiction of middle facets asymmetric anterior talocalcaneal joint ball-in-socket ankle mortise in severe cases C sign = C-shaped outline of the medial talar dome + posteroinferior sustentaculum on lateral radiograph (from bone bridge between talar dome + sustentaculum)
CT (coronal scan):
bony bar bridging the middle facet of subtalar joint narrowed middle facet with reactive cystic + hypertrophic changes downward or horizontal slope of sustentaculum, instead of upward
Dx: requires cross-sectional imaging for diagnosis
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Talonavicular coalition
Calcaneocuboid coalition
Cubonavicular coalition
Rx: orthotics, casting, NSAID, steroid injections, physical therapy, resection, arthrodesis DDx: acquired intertarsal ankylosis (infection, trauma, arthritis, surgery)
Tarsal tunnel syndrome
= entrapment / compression neuropathy (analogous to carpal tunnel syndrome) of
posterior tibial nerve (most common)
its terminal branches (= medial and lateral plantar nn., medial calcaneal n.)
Tarsal tunnel = fibro-osseous passageway from level of medial malleolus to navicular bone distally Medial floor: tibia, talus, sustentaculum tali, medial wall of calcaneus Lateral roof: deep fascia of leg, flexor retinaculum = lacinate lig., abductor hallucis Contents: medial ankle tendons (tibialis posterior, flexor hallucis longus, flexor digitorum longus) + posterior tibial nerve and artery and veins Cause:
intrinsic (mass effect): ganglion cyst, neural sheath tumor, lipoma, tenosynovitis of flexor hallucis longus, marked varicosities, accessory muscle, fracture, fibrosis of chronic ankle sprain, rheumatoid arthritis, diabetes
extrinsic (tension): tarsal colation, excessive pronation, valgus / varus heel, repetitive stress (jogger's foot)
burning pain, tingling, numbness, nocturnal paresthesia along plantar surface of heel, foot and toes
radiation of paresthesia to medial aspect of calf (Valleix phenomenon)
positive Tinel sign = percussion of posterior tibial n. posteroinferiorly from medial malleolus causes paresthesia
mass in tarsal tunnel (ganglion, neurilemoma, lipoma, thickened flexor retinaculum, muscle) muscle edema from denervation in abductor hallucis (supplied by medial plantar nerve) / abductor digiti minimi (supplied by lateral plantar nerve) fracture of sustentaculum tali / medial tubercle of posterior talar process serpiginous varicosities Rx: orthotics, release
Thalassemia Syndromes
= inherited disorders of hemoglobin synthesis typically seen in individuals of Mediterranean descent
Physiologic hemoglobins:
in adulthood:
Hb A (98% = 2 - and 2 -chains);
Hb A2(2% = 2 - and 2 -chains)
in fetal life:
Hb F (= 2 - and 2 -chains)
rapidly decreasing up to 3 months of newborn period
A. ALPHA-THALASSEMIA
= decreased synthesis of a-chains leading to excess of -chains + -chains (Hb H = 4 -chains; Hb Bart = 4 -chains)
disease begins in intrauterine life as no fetal hemoglobin is produced
homozygosity is lethal (lack of oxygen transport)
B. BETA-THALASSEMIA
= decreased synthesis of -chains leading to excess of -chains + -chains (= fetal hemoglobin)
disease manifest in early infancy
(a) homozygous defect = thalassemia major = Cooley anemia
(b) heterozygous defect = thalassemia minor
Thalassemia Major
= COOLEY ANEMIA = MEDITERRANEAN ANEMIA
= HEREDITARY LEPTOCYTOSIS = -THALASSEMIA
= most severe form with trait inherited from both parents (= homozygous form)
Incidence: 1% for American Blacks; 7.4% for Greek population; 10% for certain Italian populations Age: develops after newborn period within first 2 years of life retarded growth
elevated serum bilirubin
hyperpigmentation of skin
hyperuricemia
secondary sexual characteristics retarded, normal menstruation rare (primary gonadotropin insufficiency from iron overload in pituitary gland)
hypochromic microcytic anemia (Hb 2 3 g/dL), nucleated RBC, target cells, reticulocytosis, decrease in RBC survival, leukocytosis
susceptible to infection (leukopenia secondary to splenomegaly)
bleeding diathesis (secondary to thrombocytopenia)
@ Skull:
mongoloid facies
marrow expansion of diploe: widening of diploic space with coarsened trabeculations and displacement (from marrow hyperplasia = extramedullary hematopoiesis) thinning of outer table frontal bossing severe hair-on-end appearance (frontal bone, NOT inferior to internal occipital protuberance)
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marrow expansion in paranasal sinuses: impaired pneumatization of maxillary antra + mastoid sinuses narrowing of nasal cavity rodent facies = ventral displacement of incisors (marrow overgrowth in maxillary bone) with dental malocclusion
lateral displacement of orbits
@ Peripheral skeleton:
earliest changes in small bones of hands + feet (>6 months of age)
diffuse osteopenia: atrophy + coarsening of trabeculae (from marrow hyperplasia) prominence of nutrient foramina widened medullary spaces with thinning of cortices Erlenmeyer flask deformity = bulging of normally concave outline of metaphyses premature fusion of epiphyses (10%), usually at proximal humerus + distal femur arthropathy (secondary to hemochromatosis + CPPD + acute gouty arthritis) regression of peripheral skeletal changes (as red marrow becomes yellow)
@ Chest:
cardiac enlargement + congestive heart failure (secondary to anemia) paravertebral masses (= extramedullary hematopoiesis)
@ Ribs
costal osteomas = bulbous widening of posterior aspect of ribs with thinned cortices undertubulated broad ribs heterogeneous rib ossification: localized lucencies cortical erosion rib-within-rib appearance
@ Abdomen:
hepatosplenomegaly gallstones
Cx: (1) Pathologic fractures (2) Iron overload + hemosiderosis from frequent blood transfusion therapy (absent puberty, diabetes mellitus, adrenal insufficiency, myocardial insufficiency)
Prognosis: usually death within 1st decade Rx: systematic transfusion has lessened the severity of skeletal abnormalities DDx: chronic anemia, storage diseases, fibrous dysplasia
Thalassemia Intermedia
= subgroup of homozygous form
milder clinical presentation
not requiring hypertransfusion to maintain an adequate hematocrit
Prognosis: | longer life expectancy |
Thalassemia Minor
= beta-thalassemia trait inherited from one parent (= heterozygous)
usually asymptomatic except for periods of stress (pregnancy, infection)
microcytic hypochromic anemia (Hb 9 11 g/dL)
occasionally jaundice + splenomegaly
Thanatophoric Dysplasia
= sporadic lethal skeletal dysplasia characterized by severe rhizomelia (micromelic dwarfism) transmitted by a dominant gene mutation
Incidence: 6.9:100,000 births; 1:6,400 16,700 births; Most common lethal bone dysplasia after osteogenesis imperfecta type II
severe respiratory distress (early in life)
hypotonic infants
protuberant abdomen
extended arms + abducted externally rotated thighs
@ Head
large head with short base of skull + prominent frontal bone occasionally trilobed cloverleaf skull = Kleeblattsch del
@ Chest radiograph (PATHOGNOMONIC)
narrow chest short horizontal ribs: not extending beyond anterior axillary line cupped anterior ends
short curved telephone handle humeri H- / U-shaped vertebra plana small scapula + normal clavicles
@ Spine
normal length of trunk reduction of interpediculate space of last few lumbar vertebrae extreme generalized platyspondyly = severe H- / U-shaped vertebra plana excessive intervertebral space height
@ Pelvis (hypoplastic iliac bones)
iliac wings small + square (vertical shortening but wide horizontally) flat acetabulum narrow sacrosciatic notch short pubic bones
@ Extremities
severe micromelia + bowing of extremities metaphyseal flaring = telephone handle appearance of long bones thornlike projections in metaphyseal area polydactyly
OB-US (findings may be seen very early in pregnancy):
polyhydramnios (71%) short-limbed dwarfism with extremely short + bowed telephone receiver -like femurs extremely small hypoplastic thorax with short ribs + narrowed in anteroposterior dimension protuberant abdomen macrocrania with frontal bossing hydrocephalus (increased HC:AC ratio) cloverleaf skull (in 14%) (DDx: encephalocele) diffuse platyspondyly redundant soft tissues
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Prognosis: often stillborn; uniformly fatal within a few hours / days after birth (respiratory failure) DDx: (1) Ellis-van Creveld syndrome (extra digit, acromesomelic short limbs) (2) Asphyxiating thoracic dysplasia (less marked bone shortening, vertebrae spared)
(3) Short-rib polydactyly syndrome
(4) Homozygous achondroplasia
(5) Achondrogenesis
Thrombocytopenia-Absent Radius Syndrome
= TAR SYNDROME
= rare autosomal recessive disorder
Age: presentation at birth May be associated with: CHD (33%): ASD, tetralogy platelet count <100,000/mm3 (decreased production by bone marrow)
usually bilateral radial aplasia / hypoplasia uni- / bilaterally hypoplastic / absent ulna / humerus defects of hands, feet, legs Prognosis: death in 50% in early infancy (hemorrhage)
Thyroid Acropachy
Onset: | after >18 months following surgical / radioactive ablation of thyroid gland for hyperthyroidism (does not occur with antithyroid medication) |
Incidence: | 0.5 1% of patients with thyrotoxicosis |
clubbing, soft-tissue swelling, NO pain
eu- / hypo- / hyperthyroid state
Location: metacarpals + phalanges of hand; less commonly feet, lower legs, forearms thick spiculated lacy feathery periosteal reaction in an asymmetric distribution; mostly on radial aspect of bone
DDx: | (1) Pulmonary osteoarthropathy (painful) (2) Pachydermoperiostosis (3) Fluorosis (ligamentous calcifications) |
Transient Regional Osteoporosis
= TRANSIENT BONE MARROW EDEMA
Cause: | unknown;? overactivity of sympathetic nervous system + local hyperemia similar to reflex sympathetic dystrophy syndrome, trauma, synovitis, transient ischemia |
Regional Migratory Osteoporosis
= rapid onset of self-limiting episodes of severe localized osteoporosis and pain but repetitive occurrence of same symptoms in other regions of the same or opposite lower extremity
rapid onset of local pain
diffuse erythema, swelling, increased heat
significant disability due to severe pain on weight bearing
Age: middle-aged males Location: usually lower extremity (ie, ankle, knee, hip, foot) rapid localized osteoporosis within 4 8 weeks after onset migrating from one joint to another; may affect trabecular / cortical bone linear / wavy periosteal reaction preservation of subchondral cortical bone no joint space narrowing, bone erosion MR:
affected area has low signal intensity on T1WI, high signal intensity on T2WI (= bone marrow edema)
NUC:
increased activity
Prognosis: persists for 6 9 months in one area; cycle of symptoms may last for several years Rx: variable response to analgesics / corticosteroids
Partial Transient Osteoporosis
= variant of regional migratory osteoporosis with more focal pattern of osteoporosis, which may eventually become more generalized
(a) Zonal form = portion of bone involved, ie, one femoral condyle / one quadrant of femoral head
(b) Radial form = only one / two rays of hand / foot involved
Transient Osteoporosis of Hip
= self-limiting disease of unknown etiology
Age: typically in middle-aged males / in 3rd trimester of pregnancy in females involving left hip; M > F spontaneous onset of hip and groin pain, usually progressive over several weeks
painful swelling of joint followed by progressive
demineralization
rapid development of disability, limp, decreased range of motion
Site: hip most commonly affected; generally only one joint at a time progressive marked osteoporosis of femoral head, neck, acetabulum (3 8 weeks after onset of illness) virtually PATHOGNOMONIC striking loss of subchondral cortex of femoral head + neck region NO joint space narrowing / subchondral bone collapse NUC:
markedly increased uptake on bone scan without cold spots / inhomogeneities (positive before radiograph)
MR:
diffuse bone marrow edema involving femoral head + neck + sometimes intertrochanteric region small joint effusion
Cx: pathologic fracture common Prognosis: spontaneous recovery within 2 6 months; recurrence in another joint within 2 years possible DDx: (1) AVN (cystic + sclerotic changes, early subchondral undermining) (2) Septic / tuberculous arthritis (joint aspiration!)
(3) Monoarticular rheumatoid arthritis
(4) Metastasis
(5) Reflex sympathetic dystrophy
(6) Disuse atrophy
(7) Synovial chondromatosis
(8) Villonodular synovitis
Transient Synovitis of Hip
= OBSERVATION HIP = TRANSITORY SYNOVITIS = TOXIC SYNOVITIS = COXITIS FUGAX
= nonspecific inflammatory reaction
Most common nontraumatic cause of acute limp in a child Etiology: unknown; no organism on joint aspiration Age: 5 10 (average 6) years; M:F = 2:1 history of recent viral illness (65%)
developing limp over 1 2 days
pain in hip, thigh, knee
mild fever (25%), mildly elevated ESR (50%)
radiographs usually normal joint effusion: displacement of femur from acetabulum displacement of psoas line lateral displacement of gluteal line (least sensitive + least reliable)
regional osteoporosis (? hyperemia, disuse) NUC:
normal / slight increase in activity (excluding osteomyelitis + avascular necrosis)
Prognosis: complete recovery within a few weeks Dx: per exclusion Rx: non weight-bearing treatment DDx: trauma, Legg-Perthes disease, acute rheumatoid arthritis, acute rheumatic fever, septic arthritis, tuberculosis, malignancy
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Treacher-Collins Syndrome
= MANDIBULOFACIAL DYSOSTOSIS
= autosomal dominant disease (with new mutations in 60%) characterized by bilateral malformations of eyes, malar bones, mandible, and ears resulting in birdlike face
Incidence: 1:50,000 births Cause: defect in growth of 1st + 3rd branchial arches before the 7th to 8th week of gestation NO limb anomalies (important DDx!) extension of scalp hair growth onto cheek
microstomia
craniosynostosis narrowing of retropharyngeal space (apnea, speech difficulties) @ Eyes
antimongoloid eye slant (drooping lateral lower eyelids due to hypoplasia of lateral canthal tendon of orbicular muscle)
sparse / absent eye lashes / coloboma in lower lids
egg-shaped orbits = drooping of outer inferior orbital rim hypoplasia of lateral wall of orbits + shallow / incomplete orbital floor
@ Nose
broad / protruded nose
choanal shortening
@ Malar bone
sunken cheek due to marked hypoplasia / agenesis of zygomatic arches (= malar hypoplasia)
@ Maxilla
hypoplasia of maxilla + maxillary sinus narrow / overprojected maxilla high-arched / narrow palate
@ Mandible
retruded chin, retrognathism
dental malocclusion
pronounced micrognathia = mandibular hypoplasia with broad concave curve on lower border of body
@ Ear
dysplastic low-set auricles
preauricular skin tags / fistulas
conductive hearing loss (common)
microtia with small middle ear cavity deformed / fused / absent auditory ossicles atresia / stenosis of external auditory canal
OB-US:
polyhydramnios (from swallowing difficulty)
Prognosis: early respiratory problems (tongue relatively too large for hypoplastic mandible) Rx: surgical correction DDx: (1) Goldenhar-Gorlin syndrome (unilateral microtia + midface anomalies, hemivertebrae, block vertebrae, vertebral hypoplasia, microphthalmia, coloboma of upper lid) (2) Acrofacial dysplasia (limb malformations)
(3) Crouzon disease (maxillary hypoplasia with protrusion of mandible, hypertelorism, exophthalmos, craniosynostosis)
Trisomy D Syndrome
= Trisomy 13 15 group syndrome
Etiology: additional chromosome in D group; high maternal age severe mental retardation
hypertonic infant
cleft lip + palate
Associated with: capillary hemangioma of face + upper trunk hypotelorism coloboma, cataract, microphthalmia
malformed ear with hypoplastic external auditory canal
hyperconvex nails
postaxial polydactyly @ Skull
deficient ossification of skull cleft / absent midline structures of facial bones poorly formed orbits slanting of frontal bones microcephaly arrhinencephaly holoprosencephaly
@ Chest
thin malformed ribs diaphragmatic hernia (frequent) congenital heart disease
Prognosis: death within 6 months of age
Trisomy E Syndrome
= Trisomy 16 18 group syndrome
Etiology: additional chromosome at 18 or E group location Sex: usually female Marked phenotypic variability! hypertonic spastic infants
mental + psychomotor retardation
typical facies: micrognathia, high narrow palate with small buccal cavity, low-set deformed ears
flexed ulnar-deviated fingers + short adducted thumb
2nd finger overlapping of 3rd (CHARACTERISTIC)
Associated with: congenital heart disease in 100% (PDA, VSD); hernias; renal anomalies; eventration of diaphragm stippled epiphyses @ Skull
thin calvarium persistent metopic suture dolichocephaly with prominent occiput micrognathia due to hypoplastic mandible (most constant feature) + maxilla
@ Chest
increase in AP diameter of thorax shield deformity due to hypoplastic short sternum hypoplastic clavicles (DDx: cleidocranial dysostosis) 11 rib pairs with slender hypoplastic + tapered ribs diaphragmatic eventration (common)
@ Pelvis
small pelvis with forward rotation of iliac wings increased obliquity of acetabulum acute iliac angle (DIAGNOSTIC)
@ Hand & foot
adducted thumb = short 1st metacarpal + phalanges (DIAGNOSTIC) overlap of 2nd on 3rd finger (DIAGNOSTIC) flexed ulnar-deviated fingers short 1st toe varus deformities of forefoot + dorsiflexion of toes rocker bottom foot / extreme pes planus (frequent)
OB-US:
hydrocephalus cystic hygroma diaphragmatic hernia clubfoot overlapping index finger choroid plexus cyst (30%)
Prognosis: child rarely survives beyond 6 months of age DDx: osteogenesis imperfecta, trisomy 13 syndrome, Cockayne syndrome, Werdnig-Hoffmann disease
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Tuberculosis of Bone
Incidence: | 1 3 5% of tuberculous patients, 30% in patients with extrapulmonary tuberculosis |
Age: | any, rare in 1st year of life, M:F = 1:1 |
negative skin test excludes diagnosis
history of active pulmonary disease (in 50%)
Location: vertebral column, hip, knee, wrist, elbow Associated with: concurrent active intrathoracic tuberculosis in <50% Pathogenesis:
Hematogenous spread from
primary infection of lung (particularly in children)
quiescent primary pulmonary site / extraosseous focus
Reactivation: especially in hip
Tuberculous Arthritis
= joint involvement usually secondary to adjacent osteomyelitis / hematogenous dissemination
Incidence: 84% of skeletal tuberculosis Pathophysiology: synovitis with pannus formation leads to chondronecrosis Age: middle-aged / elderly chronic pain, weakness, muscle wasting
soft-tissue swelling, draining sinus
joint fluid: high WBC count, low glucose level, poor mucin clot formation (similar to rheumatoid arthritis)
Location: hip, knee (large weight-bearing joints) >> elbow, wrist, sacroiliac joint, glenohumeral, articulation of hand + foot Monoarticular involvement is typical!
Phemister triad: Gradual narrowing of joint space due to slow cartilage destruction (DDx: cartilage destruction in pyogenic arthritis is much quicker)
Peripherally located (= marginal) bone erosions
Juxtaarticular osteoporosis
(DDx: fungal disease, rheumatoid arthritis)
Early radiographs:
joint effusion (hip in 0%, knee in 60%, ankle in 80%) extensive periarticular osteopenia (deossification) adjacent to primarily weight-bearing joints soft tissues normal
Late radiographs:
small cystlike erosions along joint margins in non weight-bearing line opposing one another (DDx: pyogenic arthritis erodes articular cartilage) no joint space narrowing for months (CLASSIC!) articular cortical bone destruction earlier in joints with little unopposed surfaces (hip, shoulder) kissing sequestra = wedge-shaped areas of necrosis on both sides of the joint due to infection of subchondral bone increased density with extensive soft-tissue calcifications in healing phase
Cx: fibrous ankylosis, leg shortening Dx: synovial biopsy (in 90% positive), culture of synovial fluid (in 80% positive) DDx: pyogenic arthritis (central erosion of articular cartilage, early joint space narrowing, bony ankylosis)
Tuberculous Osteomyelitis
Incidence: | 16% of skeletal tuberculosis |
Age: | children <5 years (0.5 14%), rare in adults |
painless swelling of hand / foot
Location: femur, tibia, small bones of hand + foot (most common); any bone may be involved Site:
metaphysis (TYPICALLY) with transphyseal spread (in child) (DDx: pyogenic infections usually do not extend across physis)
epiphysis with spread to joint / spread from adjacent affected joint
diaphysis (<1%)
initially round / oval poorly defined lytic lesion with minimal / no surrounding sclerosis varying amounts of eburnation + periostitis advanced epiphyseal maturity / overgrowth (due to hyperemia) limb shortening from premature physeal fusion cystic tuberculosis = well-marginated round / oval radiolucent lesions with variable amount of sclerosis in children (frequent): in peripheral skeleton, symmetric distribution, no sclerosis
in adults (rare): in skull / shoulder / pelvis / spine, with sclerosis
(DDx: eosinophilic granuloma, sarcoidosis, cystic angiomatosis, plasma cell myeloma, chordoma, fungal infections, metastases)
tuberculous dactylitis = digit with exuberant lamellated / solid periosteal new-bone formation and fusiform soft-tissue swelling (children >> adults): spina ventosa ( wind-filled sail ) = ballooning dactylitis forming an enlarging cystlike cavity with erosion of endosteal cortex (end-stage disease)
DDx: (1) pyogenic osteomyelitis (no transphyseal spread) (2) syphilitic dactylitis (bilateral symmetric involvement, less soft-tissue swelling and sequestration)
(3) Sarcoidosis, hemoglobinopathies, hyperparathyroidism, leukemia
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Tuberculous Spondylitis
= POTT DISEASE
[Percival Pott (1714 1788), surgeon in London, England associated cancer of the scrotum with coal tar in chimney sweeps]
= destruction of vertebral body + intervertebral disk by tuberculous mycobacterium
Incidence: 5% of patients with tuberculosis; 25 50 60% of all skeletal tuberculosis Age: children / adults of 50 years; M > F insidious onset of back pain, stiffness
local tenderness
NO pulmonary lesions in 50%
Location: upper lumbar + lower thoracic spine (L1 most common); TYPICALLY more than one (up to 5 10) vertebrae affected Site: vertebral body (82%) with predilection for anterior part adjacent to superior / inferior sub-chondral bone plate >> posterior elements (18%) Spread:
contiguous into disk by penetrating subchondral endplate + cartilaginous endplate
subligamentous spread beneath anterior / posterior longitudinal ligaments to adjacent vertebral bodies
hematogenous spread via paravertebral venous plexus of Batson: separate foci in 1 4%
collapse of intervertebral disk space N.B.: vertebral disk space maintained longer than in pyogenic arthritis (disk itself preserved but fragmented) demineralization (= resorption of dense margin) of vertebral endplates: gouge defect = mild contour irregularity of anterior and lateral aspect of vertebral body (= erosion from subligamentous extension of tuberculous abscess) reactive sclerosis / periosteal reaction TYPICALLY absent
collapse of vertebral body: vertebra plana in children angular kyphotic deformity (= gibbus) due to preferential anterior involvement in adults
vertebra within a vertebra (= growth recovery lines) ivory vertebra (= reossification as healing response to osteonecrosis) paraspinal infection: large cold fusiform abscess in paravertebral gutters / psoas, commonly bilateral anterolateral scalloping of vertebral bodies amorphous / teardrop-shaped calcification in paraspinal area between L1 + L5 (DDx: nontuberculous abscess rarely calcifies) abscess may extend into groin / thigh / internal viscus
Cx: angular kyphosis (= gibbus deformity), scoliosis, ankylosis, osteonecrosis, paralysis (spinal cord compression from abscess, granulation tissue, bone fragments, arachnoiditis) Prognosis: 26 30% mortality rate DDx: (1) Pyogenic spondylitis (rapid destruction, multiple abscess cavities, no thickening / calcification of abscess rim, little new-bone formation, posterior elements not involved) (2) Brucellosis (gas within disk, minimal paraspinal mass, no kyphosis, predilection for lower lumbar spine)
(3) Sarcoidosis
(4) Neoplasia (multiple noncontiguous lesions, no disk destruction, little soft-tissue involvement)
Tuberculous Spondylitis without Diskitis
increasingly more common type of TB
Predilection: foreign-born (sub-Saharan Africa) Age: 40 years (10 years younger) absence of disk destruction initial multifocal vertebral involvement in 42% extraspinal skeletal involvement (frequent)
Tumoral Calcinosis
= LIPOCALCINOGRANULOMATOSIS
= rare disease with progressive large nodular juxtaarticular calcified soft-tissue masses in patients with normal serum calcium + phosphorus and no evidence of renal, metabolic, or collagen-vascular disease
Etiology: autosomal dominant (1/3) with variable clinical expressivity; unknown biochemical defect of phosphorus metabolism responsible for abnormal phosphate reabsorption + 1,25-dihydroxy-vitamin D formation Path: multilocular cystic lesions with creamy white fluid (hydroxyapatite) + many giant cells (granulomatous foreign body reaction) surrounded by fibrous capsule Age: onset mostly within 1st / 2nd decade (range of 1 79 years); M:F = 1:1; predominantly in Blacks progressive painful / painless soft-tissue mass with overlying skin ulceration + sinus tract draining chalky milklike fluid
swelling
limitation of motion
hyperphosphatemia + hypervitaminosis D
normal serum calcium, alkaline phosphatase, renal function, parathyroid hormone
@ Soft tissue
Location: paraarticular in hips > elbows > shoulders > feet, ribs, ischial spines; single / multiple joints; ALMOST NEVER knees; usually along extensor surface of joints (? initially a calcific bursitis) dense loculated multiglobular homogeneously calcified soft-tissue mass of 1 20 cm in size cystic appearance with radiolucent septa (= connective tissue) sedimentation sign = fluid-fluid levels with milk-of-calcium consistency underlying bones NORMAL increased tracer uptake of soft-tissue masses on bone scan MR:
inhomogeneous high signal intensity on T2WI (in spite of large amount of calcium) inhomogeneous lesion with low signal intensity on T1WI
@ Bone
diaphyseal periosteal reaction (diaphysitis) patchy areas of calcification in medullary cavity (calcific myelitis) increased uptake on bone scintigraphy
@ Teeth
bulbous root enlargement pulp stones = intrapulp calcifications
@ Pseudoxanthoma elasticum-like features
calcinosis cutis = skin calcifications vascular calcifications angioid streaks of retina
Prognosis: tendency for recurrence after incomplete excision Rx: phosphate depletion DDx: Chronic renal failure on hemodialysis, CPPD, paraosteoarthropathy, hyperparathyroidism
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Turner Syndrome
-
= due to nondisjunction of sex chromosomes as
complete monosomy (45, XO)
partial monosomy (structurally altered second X chromosome)
mosaicism (XO + another sex karyotype)
Incidence: 1:3,000 5,000 livebirths Associated with: coarctation, aortic stenosis, horseshoe kidney (most common) sexual infantilism (spontaneous puberty in 5 15%):
primary amenorrhea
absent secondary sex characteristics
short stature; absence of prepubertal growth spurt
webbed neck; low irregular nuchal hair line
shield-shaped chest + widely spaced nipples
mental deficiency (occasionally)
high palate; thyromegaly
multiple pigmented nevi; keloid formation
idiopathic hypertension; elevated urinary gonadotropins
@ General
normal skeletal maturation with growth arrest at skeletal age of 15 years delayed fusion of epiphyses > age 20 years osteoporosis during / after 2nd decade (gonadal hormone deficiency) coarctation of aorta (10%); aortic stenosis renal ectopia / horseshoe kidney lymphedema
@ Skull
basilar impression; basal angle >140 parietal thinning small bridged sella hypertelorism
@ Axial skeleton
hypoplasia of odontoid process + C1 osteochondrosis of vertebral plates squared lumbar vertebrae; kyphoscoliosis deossification of vertebrae small iliac wings; late fusion of iliac crests android pelvic inlet with narrowed pubic arch + small sacrosciatic notches
@ Chest
thinning of lateral aspects of clavicles thinned + narrowed ribs with pseudonotching
@ Hand + arm
positive metacarpal sign = relative shortening of 3rd + 4th metacarpal positive carpal sign = narrowing of scaphoid-lunate-triquetrum angle <117 phalangeal preponderance = length of proximal + distal phalanx exceeds length of 4th metacarpal by >3 mm shortening of 2nd + 5th middle phalanx (also in Down syndrome) drumstick distal phalanges = slender shaft + large distal head insetting of epiphyses into bases of adjacent metaphyses (phalanges + metacarpals) Madelung deformity = shortening of ulna / absence of ulnar styloid process cubitus valgus = bilateral radial tilt of articular surface of trochlea deossification of carpal bones
@ Knee
tibia vara = enlarged medial femoral condyle + depression of medial tibial plateau (DDx: Blount disease) small exostosis-like projection from medial border of proximal tibial metaphysis
@ Foot
deossification of tarsal bones shortening of 1st, 4th, and 5th metatarsals pes cavus
US:
prepubertal uterus nonvisualized / streaky ovaries (in complete monosomy); normal ovaries (in mosaic karyotype)
OB-US:
large nuchal cystic hygroma lymphangiectasia with generalized hydrops symmetrical edema of dorsum of feet CHD (20%): coarctation of aorta (70%), left heart lesions horseshoe kidney
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Bonnevie-Ullrich Syndrome
= infantile form of Turner syndrome
(1) congenital webbed neck
(2) widely separated nipples
(3) lymphedema of hands + feet
Turret Exostosis
Cause: | trauma with formation of subperiosteal hematoma |
immobile, occasionally painful lump on dorsum of finger
reduced ability to flex finger (= ossified hematoma diminishes excursion of extensor tendon)
Location: dorsum of proximal / middle phalanx of hand smooth dome-shaped extracortical mass
Ulnar Collateral Ligament Tear
Cause: | chronic overuse in throwing / other overhead motion (eg, tennis serving) generating increased valgus stress |
acute onset of sharp / gradual onset of increasing pain in medial elbow
ulnar nerve dysfunction (40%): pain, paresthesia of forearm + in 4th and 5th digits
ossification within ulnar collateral ligament (UCL) loose bodies osteoarthritis of ulnohumeral articulation osteochondritis dissecans of capitellum excessive medial joint opening on stress radiographs MR (coronal plane):
laxity / discontinuity of UCL increased signal intensity of UCL + surrounding tissues poor definition of ligament margins
Rx: rest, application of ice, NSAID, exercise, steroid injections; reconstruction of ligament
Van Buchem Disease
= GENERALIZED CORTICAL HYPEROSTOSIS
= autosomal recessive disease; may be related to hyperphosphatasemia
Cause: defect on chromosome 17 paralysis of facial nerve
auditory + ocular disturbances (in late teens secondary to foraminal encroachment)
increased alkaline phosphatase
Location: skull, mandible, clavicles, ribs, long-bone diaphyses symmetrical generalized sclerosis + thickening of endosteal cortex obliteration of diploe spinous processes thickened + sclerotic DDx: (1) Osteopetrosis (sclerosis of all bones, not confined to diaphyses) (2) Generalized hyperostosis with pachydermia (involves entire long bones, considerable pain, skin changes)
(3) Hyperphosphatasia (infancy, widened bones but decreased cortical density)
(4) Engelmann disease (rarely generalized, involves lower limbs)
(5) Pyle disease (does not involve middiaphyses)
(6) Polyostotic fibrous dysplasia (rarely symmetrically generalized, paranasal sinuses abnormal, skull involvement)
(7) Sclerosteosis = Truswell-Hansen disease (syndactyly of 2nd + 3rd fingers, nail dysplasia)
Williams Syndrome
= IDIOPATHIC HYPERCALCEMIA OF INFANCY
peculiar elfinlike facies, dysplastic dentition
neonatal hypercalcemia (not in all patients)
mental + physical retardation
@ Skeletal manifestations
osteosclerosis (secondary to trabecular thickening) dense broad zone of provisional calcification radiolucent metaphyseal bands dense vertebral end plates + acetabular roofs bone islands in spongiosa metastatic calcification craniostenosis
@ Cardiovascular manifestations
supravalvular aortic stenosis (33%), aortic hypoplasia valvular + peripheral pulmonary artery stenosis ASD, VSD stenoses of major vessels (innominate, carotids, renal arteries)
@ GI and GU tract:
colonic diverticula bladder diverticula
Prognosis: spontaneous resolution after 1 year in most Rx: withhold vitamin D + calcium DDx: Hypervitaminosis D
Wilson Disease
= hepatolenticular DEGENERATION
= autosomal recessive disease with excessive copper retention (= copper toxicosis)
Prevalence: 1:33,000 200,000; 1:90 persons is a heterozygous carrier Cause: alteration of chromosome 13 resulting in inability of liver to excrete copper into bile; hypothetically due to either (a) lysosomal defect in hepatocytes, or
(b) deficiency of biliary copper-binding proteins, or
(c) persistence of fetal mode of copper metabolism, or
(d) hepatic synthesis of high-affinity copper-binding proteins)
Age of onset: 7 50 years; hepatic manifestations predominate in children; neuropsychiatric manifestations predominate in adolescents + adults Histo: macrovesicular fat deposition in hepatocytes, glycogen degeneration of hepatocyte nuclei, Kupffer cell hypertrophy Stage 1 asymptomatic copper accumulation in hepatocytic cytosol Stage 2 redistribution of copper into hepatic lysosomes + circulation from saturated hepatocytic cytosol (a)gradual redistribution is asymptomatic
(b) rapid redistribution causes fulminant hepatic failure / acute intravascular hemolysis
Stage 3 cirrhosis, neurologic, ophthalmologic, renal dysfunction may be reversible with therapy tremor, rigidity, dysarthria, dysphagia (excessive copper deposition in lenticular region of brain)
intellectual impairment, emotional disturbance
Kayser-Fleischer ring (= green pigmentation surrounding limbus corneae) is DIAGNOSTIC
jaundice / portal hypertension (liver cirrhosis)
elevated copper concentration in serum ceruloplasmin (BEST SCREENING TEST)
decreased incorporation of orally administered radiolabeled copper into newly synthesized ceruloplasmin
Skeletal manifestations (in 2/3):
generalized deossification may produce pathologic fractures
@ Joints: shoulder (frequent), knee, hip, wrist, 2nd 4th MCP joints
articular symptoms in 75%: pain, stiffness, gelling of joints
subarticular cysts premature osteoarthritis (narrowing of joint space + osteophyte formation) osteochondritis dissecans chondrocalcinosis premature osteoarthrosis of spine, prominent Schmorl nodes, wedging of vertebrae, irregularities of vertebral plates
@ Liver (in children)
normal hepatic attenuation (fatty infiltration + copper deposition cancel each other out) normal T1 relaxation time (in spite of paramagnetic effects of copper)
@ Brain (adolescents + adults)
Location: basal ganglia, rarely thalamus cerebral white matter atrophy hypodensities, prolongation of T1 + T2
Cx: rickets + osteomalacia (secondary to renal tubular dysfunction) in minority of patients Rx: life-long pharmacologic therapy with chelation agents (penicillamine / trientine / zinc); liver transplantation
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