Radiology Review Manual (Dahnert, Radiology Review Manual)

Authors: Dahnert, Wolfgang

Title: Radiology Review Manual, 6th Edition

Copyright 2007 Lippincott Williams & Wilkins

> Table of Contents > Urogenital Tract

Urogenital Tract

Differential Diagnosis of Urogenital Disorders

Renal failure

• = reduction in renal function

• rise in serum creatinine >2.5 mg/dL

Acute Renal Failure

• = clinical condition associated with rapid steadily increasing azotemia oliguria (<500 mL urine per day) over days / weeks

• Etiology:

  • PRERENAL

    • = renal hypoperfusion secondary to systemic illness

    • 1. Fluid + electrolyte depletion

    • 2. Hemorrhage

    • 3. Hepatic failure + hepatorenal syndrome

      • abnormally elevated resistive index

    • 4. Cardiac failure

    • 5. Sepsis

      • resistive index <0.75 in 80% of kidneys

  • RENAL (most common)

    • Acute tubular necrosis:

      • ischemia, nephrotoxins, radiographic contrast, hemoglobulinuria, myoglobulinuria, myocardial infarction, burns

      • resistive index 0.75 in 91% of kidneys

    • Acute glomerulonephritis + small vessel disease:

      • acute poststrep glomerulonephritis, rapidly progressive glomerulonephritis, lupus, polyarteritis nodosa, Sch nlein-Henoch purpura, subacute bacterial endocarditis, serum sickness, Goodpasture syndrome, malignant hypertension, hemolytic uremic syndrome, drug-related vasculitis, abruptio placentae

      • normal resistive index <0.70

    • Acute tubulointerstitial nephritis:

      • drug reaction, pyelonephritis, papillary necrosis

      • abnormal resistive index

    • Intrarenal precipitation (hypercalcemia, urate, myeloma protein)

    • Arterial / venous obstruction

    • Acute cortical necrosis

  • POSTRENAL (5%)

    • = result of outflow obstruction (rare)

    • Prostatism

    • Tumors of bladder, retroperitoneum, pelvis

    • Calculus

    • hydronephrosis

  • CONGENITAL

    • bilateral renal agenesis / dysplasia / infantile polycystic kidney disease, congenital nephrotic syndrome, congenital nephritis, perinatal hypoxia

• Incidence:  ATN + prerenal disease account for 75% of acute renal failure

Chronic Renal Failure (CRF)

• = decrease in renal function over months / years

• Incidence:  end-stage renal disease in 0.01% of U.S. population; 85,000 patients/year undergo hemodialysis; 8,000 renal transplantations/year

• Etiology:

  • INFLAMMATION / INFECTION

    • Glomerulonephritis

    • Chronic pyelonephritis

    • Tuberculosis

    • Sarcoidosis

  • VASCULAR

    • Renal vascular disease

    • Bilateral renal vein thrombosis

  • DYSPROTEINEMIA

    • Myeloma

    • Amyloid

    • Cryoglobulinemia

    • Waldenstr m macroglobulinemia

  • METABOLIC

    • Diabetes

    • Gout

    • Hypercalcemia

    • Hyperoxaluria

    • Cystinosis

    • Fabry disease

  • CONGENITAL

    • Polycystic kidney disease

    • Multicystic dysplastic kidney

    • Medullary cystic disease

    • Alport syndrome

    • Infantile nephrotic syndrome

  • MISCELLANEOUS

    • Hepatorenal syndrome

    • Radiation

Musculoskeletal Manifestations of CRF

• Renal osteodystrophy = combination of 2 HPT, osteoporosis, osteosclerosis, osteomalacia, soft-tissue and vascular calcifications

• Aluminum toxicity (1 30%)

  • Cause:  ingestion of aluminum salts phosphate-binding antacids (to control hyperphosphatemia)

  • aluminum serum level >100 ng/mL

  • signs of osteomalacia (>3 insufficiency fractures with predominant involvement of ribs)

  • avascular necrosis

  • lack of osteosclerosis

  • less evidence of subperiosteal resorption

• Amyloid deposition

  • Path:  amyloid consists of ₂-microglobulin

  • Organs:  bone, tenosynovium (carpal tunnel syndrome), vertebral disk, articular cartilage + capsule, ligament, muscle

• Destructive spondyloarthropathy (15%)

  • diskovertebral junction erosion + sclerosis

  • vertebral body compression

  P.878

  • disk space narrowing

  • Schmorl node formation

  • lack of osteophytosis

  • facet involvement with subluxation

• Tendon rupture

• Crystal deposition disease

  • Type:  calcium hydroxyapatite, CPPD, calcium oxalate, monosodium urate

• Osteomyelitis + septic arthritis

• Avascular necrosis (in up to 40%)

Diabetes insipidus

• = characterized by daily production of very large volume of dilute urine (specific gravity <1.005, <200 mOsm/L)

Pituitary Diabetes Insipidus

• = Hypothalamic Diabetes Insipidus

• = vasopressin-sensitive diabetes insipidus

• = vasopressin (ADH) production is reduced to <10%

• Cause:

  • idiopathic (27%)

    • septooptic dysplasia / rare familial (autosomal dominant X-linked) / sporadic disorder

    • Histo: atrophic supraoptic nucleus

    • never associated with anterior pituitary dysfunction

  • pituitary destruction by tumor / infiltrative disorder (32%):

    in childhood:	hypothalamic glioma, tuber cinereum hamartoma, craniopharyngioma, Langerhans histiocytosis, germinoma, leukemia, complication of meningitis
    in adulthood:	sarcoidosis, TB, metastasis

    • in 60% associated with anterior pituitary dysfunction

  • pituitary destruction by surgery (20%)

    • always associated with anterior pituitary dysfunction

  • head injury (17%)

    • in 20% associated with anterior pituitary dysfunction

• A lesion in the posterior pituitary will NOT produce diabetes insipidus, because it is simply the storage space for vasopressin!

Psychogenic Water Intoxication

• = compulsive intake of large amounts of fluid, which leads to inhibition of normal vasopressin production

• water deprivation test

Nephrogenic Diabetes Insipidus

• = poor reabsorption of water in collecting ducts due to end-organ resistance to vasopressin

• Cause:

  • congenital

    • Rare X-linked recessive genetic disorder with unresponsiveness of tubules + collecting system to vasopressin (in infants + young males) with variable expression

    • Autosomal dominant form (rare)

  • acquired = nephrogenic DI syndrome

    • = disorders affecting the medulla / distal nephrons:

      • medullary + polycystic disease, sickle cell nephropathy, postobstructive uropathy, reflux nephropathy, chronic uremic nephropathy, unilateral renal artery stenosis, acute tubular necrosis, drug toxicity, analgesic nephropathy, hypokalemic + hypercalcemic nephropathy, amyloidosis, sarcoidosis

• symptoms in infancy:

  • vomiting secondary to hypernatremic dehydration

  • mental retardation

  • caloric growth failure (water favored over formula)

• symptoms after infancy:

  • increased fluid intake

  • avoiding urination

  • bilateral hydroureteronephrosis

• Rx:  thiazide diuretics, low-salt diet, encouragement of frequent micturition, indomethacin

Hypercalcemia

• mnemonic: SHAMPOO DIRT

  • Sarcoidosis

  • Hyperparathyroidism, Hyperthyroidism

  • Alkali-milk syndrome

  • Metastases, Myeloma

  • Paget disease

  • Osteogenesis imperfecta

  • Osteopetrosis

  • D vitamin intoxication

  • Immobility

  • Renal tubular acidosis

  • Thiazides

Polycythemia

• Cause:  increased level of erythropoietin (acting on erythroid stem cells) secondary to a decrease in pO₂; erythropoietin precursor is produced in juxtaglomerular epithelioid cells of kidney + converted in blood

• A. RENAL

  • intrarenal

    • Vascular impairment

    • Renal cell carcinoma (5%)

    • Wilms tumor

    • Benign fibroma

    • Simple cyst (14%)

    • Polycystic kidney disease

  • postrenal

    • Obstructive uropathy (14%)

• B. EXTRARENAL

  • liver disease

    • Hepatoma

    • Regenerating hepatic cells

  • adrenal disease

    • Pheochromocytoma

    • Aldosteronoma

    • Cushing disease

• C. CNS DISEASE

  • Cerebellar hemangioblastoma

• D. Large uterine myomas

• NOT in: renal vein thrombosis, multicystic dysplastic kidney, medullary sponge kidney

P.879

Arterial hypertension

• PRIMARY / ESSENTIAL HYPERTENSION (85 90%)

• SECONDARY HYPERTENSION

  • Renal parenchymal disease (5 10%)

  • Potentially curable secondary hypertension (1 2%)

Renovascular Hypertension

• = normalization of blood pressure following nephrectomy / reestablishment of normal renal blood flow (Dx made in retrospect)

• Incidence:  1 5% of general population; 2nd most common cause of potentially curable hypertension

• Pathophysiology:

  • usually >50% stenosis at any level in renovascular bed leads to mildly reduced pressure in glomerular afferent arteriole (pressure falls precipitously in >80% stenosis); reduced pressure stimulates release of renin followed by angiotensin-II, and aldosterone causing

    • constriction of efferent glomerular arterioles

    • increase in systemic hypertension

    • sodium retention

• Cause:

  • Atherosclerosis (60 90%) in individuals >50 years of age

  • Fibromuscular dysplasia (10 35%) in women <40 years of age

  • Neurofibromatosis

  • Pheochromocytoma

  • Fibrous bands (congenital stenosis, retroperitoneal fibrosis, postradiation artery stenosis)

  • Arteritis (Buerger disease, polyarteritis nodosa, Takayasu disease, thrombangitis obliterans, syphilitic arteritis)

  • Arteriovenous malformation / fistula

    • renin-mediated hypertension (due to renal ischemia distal to fistula)

  • Thromboembolic disease (eg, atrial fibrillation, prosthetic valve thrombi, cardiac myxoma, paradoxical emboli, atheromatous emboli)

  • Renal artery aneurysm

  • Extrinsic compression (eg, renal cyst, neoplasm, chronic subcapsular hematoma) = Page kidney

  • Middle aortic syndrome, aortic dissection, dissecting aortic aneurysm

  • Posttraumatic renovascular hypertension

    • occlusion of main renal artery

    • significant stenosis by intimal flap

    • severe renal contusion

    • segmental renal artery branch injury

• Renal artery stenosis is present in 77% of hypertensive patients!

• Renal artery stenosis is present in 32 49% of normotensive patients!

• 15 20% of patients remain hypertensive after restoration of normal renal blood flow!

Clinical findings that suggest renovascular disease:

• Onset of HTN <30 years and >50 years of age

• Hypertension refractory to therapy

• Accelerated / malignant hypertension

• Unexplained large increases in blood pressure above previously controlled / baseline values

• Symptomatic hypertension

Rx:

• Relieving renal artery stenosis

• Angiotensin-converting enzyme inhibitor

Hypertension in Children

Prevalence:   1 3%

• Coarse renal cortex scarring (36%)

• Glomerulonephritis (23%)

• Coarctation of aorta (10%)

• Renovascular disease (10%)

• Polycystic renal disease (6%)

• Hemolytic-uremic syndrome (4%)

• Catecholamine excess [pheochromocytoma, neuroblastoma] (3%)

• Renal tumor (2%)

• Essential hypertension (3%)

Arterial Hypotension

• Cause:  intrarenal hypovolemia, primary vasoconstriction, reduced glomerular filtration, depletion of intratubular urine volume

• May occur as a contrast reaction!

• Urogram reverts to normal after reversion of hypotension!

• bilateral small smooth kidneys (compared with size on preliminary films)

• increasingly dense nephrogram

• usually NO opacification of collecting system

• initially opacification of collecting system if hypotension occurs during contrast injection

Urinary Tract Infection

= pure growths of >100,000 organisms/mL urine

Prevalence:  3% of girls + 1% of boys during first 10 years of life

Underlying radiologic abnormality:

• Vesicoureteral reflux = VUR (30 40%)

• Obstructive uropathy (8%)

• Reflux nephropathy / scar formation (6%)

  • The prevalence of an underlying radiologic abnormality depends on age, sex, and frequency of previous infections!

Imaging objective:

• Identify patients at risk for reflux nephropathy

• Detect reflux nephropathy / scars

• Detect obstructive uropathy

• Minimize radiation, morbidity, and cost

  • VCUG:

    • for children <5 years of age with infection; normal results in 60 70%

  P.880

  • Renal cortical scintigraphy (DMSA / glucoheptonate):

    • to detect acute pyelonephritis (risk for scarring) / scar; with VUR there is twice the risk of cortical defects than without VUR

Gas in Urinary Tract

• Renal emphysema = renal / perirenal gas

  • Emphysematous pyelonephritis

  • Emphysematous pyelitis

  • Gas-forming perinephric abscess

  • Perinephric emphysema

• Bladder

  • Emphysematous cystitis

• Trauma

  • Penetrating trauma

  • Ureterosigmoidostomy, ileal conduit, catheterization with vesicoureteral reflux, percutaneous procedure

    • CAVE: anomalous posterior position of colon

  • Infarction of renal carcinoma (therapeutic / spontaneous)

• Fistula to urinary tract

  • Connection:  bronchus / cutis / GI tract (colon > duodenum > stomach > small bowel > appendix

  • Inflammation: chronic purulent renal infection, diverticulitis, Crohn disease

  • Neoplastic: colonic carcinoma

Retroperitoneum

Retroperitoneal Tumor by Tissue Component

• fat

  • Lipoma

  • Liposarcoma

  • Teratoma

• myxoid stroma

  • Neurogenic tumor: schwannoma, neurofibroma, ganglioneuroma, ganglioneuroblastoma, malignant peripheral nerve sheath tumor

  • Myxoid liposarcomas

  • Myxoid malignant fibrous histiocytoma

  • Desmoid tumor

  • Hemangiopericytomas

  • Leiomyomas, leiomyosarcomas

  • Malignant pericytomas

  • Rhabdomyosarcoma

  • Malignant mesenchymomas

• necrosis

  • Leiomyosarcoma

  • Paraganglioma

• cystic component

  • Lymphangioma

  • Mucinous cytsic tumor

  • Neurogenic tumor

• small round cells

  • Lymphoma

• hypervascularity

  • Paragangliomas

  • Hemangiopericytoma

  • Low-grade liposarcomas

  • Lymphoma

Primary Malignant Tumor of Retroperitoneum

• Liposarcoma

• Malignant fibrous histiocytoma

  • dystrophic calcifications in 25%

• Leiomyosarcoma

Low-density Retroperitoneal Mass

• Lipoma

  • sharply marginated, homogeneously fatty mass

• Lymphangioma

  • similar to lipoma if enough fat content

• Renal angiomyolipoma

  • intrarenal component

  • hypervascular with large feeding arteries, multiple aneurysms, laking without shunting, tortuous circum-ferential vessels, whorled parenchymal + venous phase

• Adrenal myelolipoma

  • density between fat + water

  • usually nonhomogeneous, occasionally with hemorrhage calcifications

• Xanthogranulomatous pyelonephritis

  • nonfunctioning kidney replaced by low-density material + central staghorn calculus

• Metastatic retroperitoneal tumors

• Renal cell carcinoma

• Fibrosarcoma, fibrous histiocytoma, mesenchymal sarcoma, malignant teratoma

  • density close to muscle

• Liposarcoma

Calcified Retroperitoneal Mass

• NONTUMORAL

  • Exuberant callus formation

  • Posttraumatic calcified hematoma

  • Myositis ossificans

  • Foreign body granuloma

  • Encapsulated textiloma / gossypiboma

    • (gossypium, Latin = cottton)

    • Cause: retained surgical sponge, gauze, towel

• BENIGN NEOPLASM

  • Ganglioneuroma

  • Schwannoma

  • Paraganglioma

  • Hemangiomna

  • Mature teratoma

• MALIGNANT NEOPLASM

  • Malignant fibrous histiocytoma

  • Dedifferentiated liposarcoma

  • Leiomyosarcoma

  • Malignant mesenchymoma

  • Malignant teratoma

  • Extraskeletal osteosarcoma

Adrenal Gland

Adrenal Medullary Disease

• Neuroblastoma

• Ganglioneuroblastoma

• Ganglioneuroma

• Pheochromocytoma

P.881

Adrenal Cortical Disease

• Adrenal hyperplasia

• Adrenocortical adenoma

• Adrenocortical carcinoma

• Cushing syndrome

• Conn syndrome

• Adrenogenital syndrome

Adrenocortical Hyperfunction

• Adrenogenital syndrome

• Conn syndrome = hyperaldosteronism

  • solitary unilateral adrenal adenoma + normal contralateral gland on CT may be due to:

    • aldosterone-producing adrenocortical adenoma

    • renin-responsive aldosterone-producing adenoma

    • idiopathic hyperaldosteronism with dominant hyperplastic / nonfunctional adenoma

• Cushing syndrome = hypercortisolism

  • DDx of Cushing syndrome

    • FOCAL UNILATERAL ADRENAL MASS

      • 2 4-cm focal mass in one adrenal gland + atrophy of contralateral gland = adrenal adenoma

      • >4-cm large focal mass with central necrosis in one adrenal gland + atrophy of contralateral gland = adrenal adenocarcinoma

    • BILATERAL ADRENAL ENLARGEMENT

      • diffuse uniform thickening = Cushing disease

    • MULTIPLE BILATERAL ADRENAL NODULES

      • macronodules = multinodular hyperplasia of long-standing Cushing disease

      • large nodules (autonomous ACTH-independent) = massive macronodular hyperplasia

      • small nodules = primary pigmented nodular adrenal disease

Bilateral Large Adrenals

• mnemonic:  4 H PM

  • Hodgkin disease

  • Hyperplasia

  • Hemorrhage

  • Histoplasmosis / TB

  • Pheochromocytoma

  • Metastasis

Unilateral Adrenal Mass

• Incidental discovery of adrenal mass in 1% of all CT

  • = incidentaloma!

• Risk for adrenocortical carcinoma:    0.06 4.7%

• Criteria to differentiate benign from malignant:

  • Size (too unreliable as only criterion)

    • the larger the lesion the more likely it is symptomatic

    • with known malignancy

      • 87% of lesions <3 cm are benign

      • 95% of lesions >3 cm are malignant

    • without known malignancy

      • Frequency: 1.5%

      • all malignant lesions were >5 cm

    • change in size:

      • A lesion without change in size over 6 months is likely benign!

  • Endocrinologic subclinical function

    • recommended for lesions >4 cm

      Frequency:	5%
      Cause:	pheochromocytoma (70%), adrenocortical adenoma (30%)
      Secretion:	aldosterone, cortisol, catecholamines

  • NECT attenuation (HU_NECT)

    Sensitivity for adenomas:	56%
    False-positive rate:	4%
    10 HU	= benign lipid-rich adenoma / cyst
    >10 HU	= indeterminate
    Reason:	60 70% of benign adrenocortical tumors contain intracytoplasmic fat

  • CECT for lesions >10 HU

    • 60 sec scan (HU_{CECT 1min})

    • 15-minute delayed scan (HU_{CECT 15min})

      Percentage of relative enhancement washout= [HUCECT 1min HUCECT 15min] / [HUCECT 1min HUNECT] 100
      washout >60%	= lipid-poor adenoma
      washout 60%	= indeterminate mass
      Reason:	malignant vessels have an increased capillary permeability with prolonged retention of contrast material
      Results:	95% sensitive, 97% specific

  • Chemical shift MRI:

    • Reason:  fat protons precess faster than water

    • fat + water summate to intermediate signal intensity on in-phase images

    • fat + water signals cancel each other out to low signal intensity on out-of-phase images = adenoma

    • Results:  10% overlap between benign + malignant; 90% of lesions between 10 HU and 30 HU on CT correctly classified

  • Adrenal biopsy

    Accuracy:	96 100% for malignancy
    Insufficient material:	4 19%
    Cx: 8 12% (bleeding, pneumothorax, infection, tumor tracking); several deaths reported after Bx of pheochromocytoma

  • FDG-PET

    SUV:	>4 for metastatic disease (from lung, colon, melanoma, lymphoma)
    FN:	renal cell carcinoma

  • Large size, irregularity, inhomogeneity are suggestive of malignancy

• mnemonic:  PLAN My HAM

  • Pheochromocytoma

  • Lymphoma

  • Adenoma

  • Neuroblastoma

  • Myelolipoma

  • Hemorrhage

  • Adenocarcinoma

  • Metastasis

P.882

Small Unilateral Adrenal Tumor

• Cortical adenoma (in 1 9% of autopsies)

  • <10 HU imply (in 96%) an adenoma

• Metastasis

• Pheochromocytoma

• Asymmetric hyperplasia

• Granulomatous disease (TB, histoplasmosis)

  • diffuse enlargement / discrete mass

  • central cystic changes calcification

• Myelolipoma

Large Solid Adrenal Mass

• Cortical carcinoma

• Pheochromocytoma

• Neuroblastoma / ganglioneuroma

• Myelolipoma

• Metastasis

• Hemorrhage

• Inflammation

• Abscess (eg, histoplasmosis, tuberculosis)

• Hemangioma

Malignant Adrenal Mass

• Adrenal cortical carcinoma

• Angiosarcoma

• Lymphoma

• Malignant pheochromocytoma

• Metastasis (in 4% without known primary; in 25 72% with known primary)

Cystic Adrenal Mass

• Pseudocyst: old hemorrhage / infarction

• Vascular cystic space (endothelial lining): lymphangioma, hemangioma

• True cyst (epithelial lining): glandular cyst, embryonal cyst, mesothelial inclusion cyst

• Parasitic cyst: hydatid cyst

• Hemorrhagic complication / degeneration of a tumor: cystic adenoma, cystic pheochromocytoma, cystic adenomatoid tumor, cystic adrenocortical carcinoma, schwannoma

• Neuroblastoma (rare)

• Cortical adenoma with low density

Adrenal Calcification

• TUMOR

  • Neuroblastoma

  • Pheochromocytoma

  • Adrenal adenoma

  • Adrenal carcinoma

  • Dermoid

• VASCULAR

  • Hemorrhage (neonatal, sepsis)

• INFECTION

  • Tuberculosis

  • Histoplasmosis

  • Waterhouse-Friderichsen syndrome

• ENDOCRINE

  • Addison disease (TB)

• OTHERS

  • Wolman disease

Kidney

Developmental Renal Anomalies

Numerary Renal Anomaly

• Supernumerary kidney

• Complete / partial renal duplication

• Abortive calyx

• Unicaliceal (unipapillary) kidney

Renal Underdevelopment

• Congenital renal hypoplasia

• Renal agenesis

• Renal dysgenesis

Renal Ectopia

• Normal location of kidneys: 1st 3rd lumbar vertebra

  Incidence:	0.2% (autopsy series)
  Cause:	failure of kidney to ascend by 8 weeks GA
  At risk of:	hydronephrosis due to UPJ obstruction, infection, calculi

• unusual developmental funny-looking calices often misinterpreted as obstructive

• loop-to-loop colon = abnormal looped configuration of colon occupying the renal fossa

Longitudinal Renal Ectopia

• Location:  pelvic, sacral, lower lumbar level, intrathoracic; L > R

• must demonstrate aberrant arteries

• DDx:  displacement through diaphragmatic hernia (nonaberrant); hypermobile kidney

Pelvic kidney

• = ectopic kidney due to failure of renal ascent

• Incidence:  1:725 births

• May be associated with:

  • vesicoureteral reflux

  • hydronephrosis due to abnormally high insertion of ureter into renal pelvis

  • hypospadia (common)

  • contralateral renal agenesis

• blood supply via iliac vessels / aorta

• nonrotation = anteriorly positioned renal pelvis (common)

Crossed Renal Ectopia

= kidney located on opposite side of midline from its ureteral orifice; usually L > R and crossed kidney inferior to normal kidney

• fused (common)

• separate (rare)

• invariably aberrant renal arteries

• distal ureter inserts into trigone on the side of origin

Renal Fusion

• = lump, cake, disk, horseshoe

P.883

• Cx: aberrant arteries may cross and obstruct ureter

Horseshoe kidney

Discoid / pancake kidney

• = bilateral fused pelvic kidneys

• Associated with:

  • abnormal testicular descent, tetralogy of Fallot, vaginal agenesis, sacral agenesis, caudal regression, anal anomalies

Renal Malrotation

• collecting structures may be positioned ventrally (most common), lateral (rare), dorsal (rarer), transverse (along AP axis)

• funny-looking calices = developmental usually nonobstructive ectasia

Absent Renal Outline on Plain Film

• ABSENT KIDNEY

  • Congenital absence

  • S/P nephrectomy

• SMALL KIDNEY

  • Renal hypoplasia

  • Renal atrophy

• RENAL ECTOPIA

  • Pelvic kidney

  • Crossed fused ectopia

  • Intrathoracic kidney

• OBLITERATION OF PERIRENAL FAT

  • Perirenal abscess

  • Perirenal hematoma

  • Renal tumors

Nonvisualized Kidney on Excretory Urography

• ABSENCE OF KIDNEY

  • Agenesis

  • Surgical absence

  • Renal ectopia

• LOSS OF PERFUSION

  • Chronic infarction

  • Unilateral renal vein thrombosis

• TRAUMA

  • Thrombosis of main renal artery

  • Severe contusion (with renal vascular spasm)

  • Avulsion of renal pedicle

• HIGH-GRADE URINARY OBSTRUCTION

  • Hydronephrosis

  • Ureteropelvic junction obstruction

• REPLACED NORMAL RENAL PARENCHYMA

  • Multicystic dysplastic kidney

  • Unilateral polycystic kidney disease

  • Renal tumor (RCC, TCC, Wilms tumor)

  • Xanthogranulomatous pyelonephritis

Unilateral Large Smooth Kidney

• PRERENAL

  • arterial: acute arterial infarction

  • venous: acute renal vein thrombosis

• INTRARENAL

  • congenital: duplicated pelvicaliceal system, crossed fused ectopia, multicystic dysplastic kidney, adult polycystic kidney (in 8% unilateral)

  • infectious: acute bacterial nephritis

  • adaptation: compensatory hypertrophy

• C. POSTRENAL

  • collecting system: obstructive uropathy

• mnemonic:  AROMA

  • Acute pyelonephritis

  • Renal vein thrombosis

  • Obstructive uropathy

  • Miscellaneous (compensatory hypertrophy, duplication)

  • Arterial obstruction (infarction)

Bilateral Large Kidneys

Average renal length by x-ray: M = 13 cm; F = 12.5 cm

• PROTEIN DEPOSITION

  • amyloidosis, multiple myeloma

• INTERSTITIAL FLUID ACCUMULATION

  • acute tubular necrosis, acute cortical necrosis, acute arterial infarction, renal vein thrombosis

• CELLULAR INFILTRATION

  • Inflammatory cells: acute interstitial nephritis, acute bacterial nephritis

  • Malignant cells: leukemia / lymphoma, bilateral Wilms tumor, nephroblastomatosis

• PROLIFERATIVE / NECROTIZING DISORDERS

  • Glomerulonephritis (GN)

    • acute (poststreptococcal) GN, rapidly progressive GN, idiopathic membranous GN, lobular GN, membranoproliferative GN, IgA nephropathy, glomerulosclerosis, glomerulosclerosis related to heroin abuse

  • Multisystem disease

    • polyarteritis nodosa, systemic lupus erythematosus, Wegener granulomatosis, allergic angitis, diabetic glomerulosclerosis, Goodpasture syndrome (lung hemorrhage + glomerulonephritis), Sch nlein-Henoch syndrome (anaphylactoid purpura), thrombotic thrombocytopenic purpura, focal glomerulonephritis associated with subacute bacterial endocarditis

• URINE OUTFLOW OBSTRUCTION

  • bilateral hydronephrosis: congenital / acquired

• HORMONAL STIMULUS

  • acromegaly, compensatory hypertrophy, nephromegaly associated with cirrhosis / hyperalimentation / diabetes mellitus

• DEVELOPMENTAL

  • bilateral renal duplication, horseshoe kidney, polycystic kidney disease

• MISCELLANEOUS

  • acute urate nephropathy, glycogen storage disease, hemophilia, sickle cell disease, Fabry disease, physiologic response to contrast material and diuretics

mnemonic:  FOG P

P.884

Bilateral Small Kidneys

• PRERENAL = VASCULAR

  • Arterial hypotension (acute)

  • Generalized arteriosclerosis

  • Atheroembolic disease

  • Benign & malignant nephrosclerosis

• INTRARENAL

  • Hereditary nephropathies:

    • medullary cystic disease, hereditary chronic nephritis (Alport syndrome)

  • Chronic glomerulonephritis

  • Amyloidosis (late)

• POSTRENAL

  • Papillary necrosis

• CAUSES OF UNILATERAL SMALL KIDNEY

  • occurring bilaterally

• mnemonic: CAPE HANA

  • Chronic glomerulonephritis

  • Arteriosclerosis

  • Papillary necrosis

  • Embolic disease (secondary to atherosclerosis)

  • Hypotension

  • Alport syndrome

  • Nephrosclerosis

  • Amyloidosis (late)

Unilateral Small Kidney

• PRERENAL = VASCULAR

  • Lobar infarction

  • Chronic infarction

  • Renal artery stenosis

  • Radiation nephritis

• INTRARENAL = PARENCHYMAL

  • Congenital hypoplasia

  • Multicystic dysplastic kidney (in adult)

  • Postinflammatory atrophy

• POSTRENAL = COLLECTING SYSTEM

  • Reflux nephropathy = chronic atrophic pyelonephritis

  • Postobstructive atrophy

• mnemonic:  RIP R HIP

  • Reflux atrophy

  • Ischemia (renal artery stenosis)

  • Postobstructive atrophy

  • Radiation therapy

  • Hypoplasia (congenital)

  • Infarction

  • Postinflammatory atrophy

Increased Echogenicity of Renal Cortex

• = RENAL MEDICAL DISEASE

• = diffuse increase in cortical echogenicity with preservation of corticomedullary junction

• Path:  deposition of collagen / calcium in interstitial, glomerular, tubular, vascular disease

• echointensity of cortex greater than liver / spleen equal to renal sinus

• renal size may be normal; enlarged kidneys suggest active stage of renal disease; small kidneys suggest chronic + often end-stage renal disease

• Cause:

  • Acute / chronic glomerulonephritis

  • Renal transplant rejection

  • Lupus nephritis

  • Hypertensive nephrosclerosis

  • Renal cortical necrosis

  • Methemoglobulinuric renal failure

  • Alport syndrome

  • Amyloidosis

  • Diabetic nephrosclerosis

  • Nephrotoxin-induced acute tubular necrosis

  • End-stage renal disease

Hyperechoic Renal Pyramids in Children

• NEPHROCALCINOSIS

  • iatrogenic (most common cause):

    furosemide (Rx for BPD), vitamin D (Rx for hypophosphatemic rickets)

  • noniatrogenic:

    • Idiopathic hypercalcemia

    • Williams syndrome

    • Absorptive hypercalcemia

    • Hyperparathyroidism

    • Milk-alkali syndrome

    • Kenny-Caffey syndrome

    • Distal renal tubular acidosis

    • Malignant tumors

    • Chronic glomerulonephritis

    • Sj gren syndrome (distal RTA)

    • Sarcoidosis

• METABOLIC DISEASE

  • Gout

  • Lesch-Nyhan syndrome (urate)

  • Fanconi syndrome

  • Glycogen storage disease (distal RTA)

  • Wilson disease (distal RTA)

  • Alpha-1 antitrypsin deficiency

  • Tyrosinemia

  • Cystinosis

  • Oxalosis

  • Crohn disease

• HYPOKALEMIA

  • Primary aldosteronism

  • Pseudo-Bartter syndrome

• PROTEIN DEPOSITS

  • Infant dehydration with presumed Tamm-Horsfall proteinuria

  • Toxic shock syndrome

• VASCULAR CONGESTION

  • Sickle cell anemia

• INFECTION

  • Candida / CMV nephritis

  • AIDS-associated Mycobacterium avium-intracellulare

• FIBROSIS OF RENAL PYRAMIDS

• CYSTIC MEDULLARY DISEASE

  • Medullary sponge kidney

  • Congenital hepatic fibrosis with tubular ectasia

P.885

• INTRARENAL REFLUX

  • Chronic pyelonephritis

Iron Accumulation in Kidney

• RENAL CORTEX

  • Paroxysmal nocturnal hemoglobulinuria (= intravascular extrasplenic hemolysis)

  • Sickle cell anemia

• RENAL MEDULLA

  • Hemorrhagic fever with renal syndrome (uncommon viral illness caused by Hanta virus)

    • Triad:

      • renal medullary hemorrhage

      • right atrial hemorrhage

      • necrosis of anterior pituitary

Depression of Renal Margins

• Fetal lobation

  • notching between normal calices

• Splenic impression

  • flattened upper outer margin of left kidney

• Chronic atrophic pyelonephritis

  • indentation over clubbed calices

• Renal infarct

  • normal calices

• Chronic renal ischemia

  • normal calices

Enlargement of Iliopsoas Compartment

• INFECTION

  • from retroperitoneal organs

    • Renal infection

    • Complicated pancreatitis

    • Postoperative aortic graft infection

  • from spine

    • Osteomyelitis / postoperative complication of bone surgery

    • Diskitis / postoperative complication from disk surgery

  • from GI tract

    • Crohn disease

    • Appendicitis

  • others

    • Pelvic inflammatory disease / postpartum infection

    • Sepsis

• HEMORRHAGE

  • Coagulopathy and anticoagulant therapy

  • Ruptured aortic aneurysm

  • Postoperative aneurysm repair / other surgery / trauma

• NEOPLASTIC DISEASE

  • extrinsic

    • Lymphoma

    • Metastatic lymphadenopathy

    • Bone metastases with soft-tissue involvement

    • Retroperitoneal sarcoma

  • intrinsic

    • Muscle tumors

    • Nervous system tumors

    • Lipoma / liposarcoma

• MISCELLANEOUS

  • Pseudoenlargement of psoas muscle compared with de facto atrophy of contralateral side in neuromuscular disease

  • Fluid collections

    • urinoma, lymphocele, pancreatic pseudocyst, enlargement of iliopsoas bursa

  • Pelvic venous thrombosis

    • diffuse swelling of all muscles (edema)

Renal Mass

Bilateral Renal Masses

• MALIGNANT TUMOR

  • Malignant lymphoma / Hodgkin disease

  • Metastases

  • Renal cell carcinoma

  • Wilms tumor

• BENIGN TUMOR

  • Angiomyolipoma

  • Nephroblastomatosis

• CYSTS

  • Adult polycystic kidney disease

  • Acquired cystic kidney disease

Renal Mass in Neonate

• UNILATERAL

  • Multicystic kidney (15%)

  • Hydronephrosis (25%)

    • UPJ obstruction

    • upper moiety of duplication

      Most Common Age at Presentation for Solid Renal Neoplasms

  P.886

  • Renal vein thrombosis

  • Mesoblastic nephroma

    • most common primary renal neoplasm in 1^st month of life

  • Rare: Wilms tumor, teratoma

• BILATERAL

  • Hydronephrosis

  • Polycystic kidney disease

  • Multicystic kidney + contralateral hydronephrosis

  • Nephroblastomatosis

  • Bilateral multicystic kidney

Renal Mass in Older Child

• SINGLE MASS

  • single solid mass

    • Wilms tumor (87%)

    • Clear cell sarcoma of kidney (6%)

    • Mesoblastic nephroma (2%)

    • Rhabdoid tumor (2%)

    • Renal cell carcinoma (<0.5%)

    • Teratoma

    • Intrarenal neuroblastoma

  • single cystic mass

    • Focal hydronephrosis

    • Multilocular cystic nephroma

    • Traumatic cyst, abscess

• MULTIPLE MASSES

  • Nephroblastomatosis

  • Multiple Wilms tumors

  • Angiomyolipoma

  • Lymphoma (<0.5%)

  • Leukemia

  • Adult polycystic kidney disease

  • Abscesses

Growth Pattern of Renal Lesions

Renal Lesion with Expansile Growth Pattern

• Renal cell carcinoma

• Oncocytoma

• Angiomyolipoma

• Juxtaglomerular tumor

• Metastatic tumor (eg, lymphoma)

• Mesenchymal tumor

Renal Lesions with Infiltrative Growth Pattern

• Imaging hallmarks:

  • growth initially respects renal contour

  • invasion of normal structures

  • poorly defined interface between normal renal parenchyma and lesion

  • enlarged kidney with preservation of reniform shape

  • IVP:

    • decreased / absent nephrogram

  • Angio:

    • vascular encasement, pruning, amputation

    • no vascular displacement

  • CT:

    • poorly marginated area of diminished enhancement

    • encasement of collecting system without displacement

    • replacement of renal sinus fat

  • US:

    • poorly circumscribed hypo- / hyperechoic regions

• NEOPLASM

  • lymphoproliferative

    • Lymphoma / leukemia

    • Extramedullary plasmacytoma

  • epithelial tumor of renal parenchyma

    • Renal cell carcinoma (unusual)

    • High-grade and sarcomatoid type of RCC

  • epithelial tumors of the renal pelvis

    • Invasive transitional cell carcinoma

      • mass arises from collecting system

    • Squamous cell carcinoma

  • medullary tumor of uncertain cell origin

    • Collecting duct carcinoma

    • Renal medullary carcinoma

  • metastases, esp. lung cancer

  • renal sarcomas

  • pediatric tumor

    • Mesoblastic nephroma

    • Rhabdoid tumor of the kidney

    • Nephroblastomatosis

    • Primitive neuroectodermal tumor

    • Wilms tumor (unusual)

• INFLAMMATION

  • Bacterial pyelonephritis

  • Xanthogranulomatous pyelonephritis

  • Renal parenchymal malacoplakia

Local Bulge in Renal Contour

• CYST

  • Simple renal cyst

• TUMOR

  • Adenocarcinoma

  • Angiomyolipoma

  • Pseudotumor

• INFECTION

  • Subcapsular abscess

  • XGP

• TRAUMA

  • Subcapsular hematoma

• DILATED COLLECTING SYSTEM

Unilateral Renal Mass

Solid Renal Mass

• TUMORS

  • primary malignant:

    • epithelial tumor of renal parenchyma:

      • adenocarcinoma (83%), papillary neoplasm (14%), chromophobe carcinoma (4%), renal neuroendocrine tumors (carcinoid, small cell carcinoma), Wilms tumor (6%),

    • epithelial tumor of renal pelvis:

      • TCC (8%), squamous cell carcinoma

    • medullary tumor:

      • renal medullary carcinoma, renal collecting duct carcinoma = Bellini duct carcinoma (1%)

    • renal sarcoma (2%)

    P.887

    in horseshoe kidney:

    • adenocarcinoma (45%), Wilms tumor (28%), transitional cell carcinoma (20%)

  • secondary malignant:

    • malignant lymphoma / Hodgkin disease, metastases, invasive transitional cell carcinoma

  • benign:

    • adenoma, oncocytoma, hamartoma (mesoblastic nephroma, angiomyolipoma, myolipoma, lipoma, leiomyoma, fibroma), hemangioma

• INFLAMMATORY MASSES

  • acute focal pyelonephritis, renal abscess, xanthogranulo- matous pyelonephritis, malacoplakia, tuberculoma

Fluid-filled Mass

• A. CYSTS

  • Simple renal cyst

  • Inherited cystic disease:

    • multicystic dysplastic kidney disease (Potter type II), multilocular cystic nephroma

  • Focal hydronephrosis

• B. VASCULAR

  • Arteriovenous malformation

  • Arteriovenous fistula

    • = single dilated artery + vein

    • tortuous varices over time

    • enlargement of renal vein

    • Cx: hydronephrosis

• Lesions <1 cm often cannot be clearly characterized

• Lesions 1 1.5 cm can often be ignored, particularly in elderly / patients with significant other disease

Calcified Renal Mass

• A calcified renal mass is malignant in 75% of cases!

• Lesions with

  • nonperipheral calcifications are malignant in 87%!

  • peripheral calcifications are malignant in 20%!

• A. TUMOR

  • Renal cell carcinoma (calcifies in 8 20%)

    • calcifications generally nonperipheral, sometimes along fibrous capsule

  • Wilms tumor

  • Transitional cell carcinoma (rare)

  • Osteosarcoma of renal capsule

  • Metastasis

• B. INFECTION

  • Abscess

    • Tuberculous abscess frequently calcifies!

    • Pyogenic abscess rarely calcifies!

  • Echinococcal cyst

    • Renal involvement in 3% of hydatid disease;

    • 50% of echinococcal cysts calcify

  • Xanthogranulomatous pyelonephritis

    • large obstructive calculus in >70%

• C. CYSTS

  • Calcification is related to prior hemorrhage or infection!

  • 1. Simple renal cyst (calcifies in 1 3%)

    • thin peripheral eggshell -like calcification

  • 2. Multicystic dysplastic kidney (in adult)

  • 3. Autosomal dominant polycystic kidney disease

  • 4. Milk of calcium (cyst, caliceal diverticulum, obstructed hydrocalyx)

  • DDx: residual pantopaque used in cyst puncture

• D. VASCULAR

  • Subcapsular / perirenal hematoma

  • Renal artery aneurysm

    • circular cracked eggshell appearance

  • Congenital / posttraumatic arteriovenous malformation

  • Arteriosclerosis in severe atherosclerotic disease, diabetes mellitus, hyperparathyroidism

  • Sloughed papilla in papillary necrosis

Avascular Mass in Kidney

• mnemonic:  CHEAT

  • Cyst

  • Hematoma

  • Edema

  • Abscess

  • Tumor

Hyperechoic Renal Nodule

• MALIGNANT TUMOR

  • Renal cell carcinoma

  • Angiosarcoma

  • Liposarcoma

  • Undifferentiated sarcoma

  • Lymphoma

• BENIGN TUMOR

  • Angiomyolipoma

  • Lipoma

  • Oncocytoma

  • Cavernous hemangioma

• INFARCT

• HEMATOMA

Hyperattenuating Renal Mass on NECT

• BENIGN

  • Complicated benign cyst: hemorrhagic, protein-rich, gelatinous

  • Leiomyoma

  • Angiomyolipoma (rare)

  • Thrombosed renal vein

• MALIGNANT

  • Metastasis from thyroid carcinoma

  • Renal cell carcinoma

Focal Area of Increased Renal Echogenicity

• NONNEOPLASTIC

  • Chronic renal infarction

  • Acute focal bacterial nephritis

• BENIGN TUMOR

  • Angiomyolipoma

  • Cavernous renal hemangioma

  • Oncocytoma

• MALIGNANCY

  • Renal cell carcinoma

  • Angiosarcoma

  • Undifferentiated sarcoma

  • Metastasis

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Fat-containing Renal Mass

• Angiomyolipoma

• Lipoma, liposarcoma

• Teratoma

• Wilms tumor

• Xanthogranulomatous pyelonephritis

• Oncocytoma engulfing renal sinus fat

• Renal cell carcinoma

  • invasion of perirenal fat

  • intratumoral metaplasia into fatty marrow (in 32% if RCCs <3 cm)

• If a lesion contains fat + calcium RCC is likely, not angiomyolipoma!

Renal Sinus Mass

• TUMORS

  • Transitional cell carcinoma

  • Lymphoma

  • Metastasis to sinus lymph nodes

  • Mesenchymal tumor: lipoma, fibroma, myoma, hemangioma

  • Plasmacytoma

  • Myeloid metaplasia

• MISCELLANEOUS

  • Sinus lipomatosis

  • Parapelvic cyst

  • Saccular aneurysm

  • Urinoma

Hypoechoic Renal Sinus

• SOLID

  • Fibrolipomatosis

  • Column of Bertin

  • Duplex kidney

  • TCC / RCC

• CYSTIC

  • Renal sinus cysts

  • Caliectasis

  • Dilated veins, varix

  • Aneurysm, arteriovenous malformation

Renal pseudotumor

• = normal renal tissue mimicking a renal neoplasm

• A. PRIMARY / CONGENITAL

  • Large column of Bertin

    • = large septum / cloison of Bertin = large cloison = focal cortical hyperplasia = benign cortical rest = focal renal hypertrophy

    • = persistence of normal septal cortex / excessive infolding of cortex usually in the presence of partial or complete duplication

    • Location: between upper and interpolar portion

    • mass <3 cm in largest diameter

    • lateral indentation of renal sinus

    • deformation of adjacent calices + infundibula

    • mass continuous with renal cortex

    • enhancement pattern like renal cortex

    • echogenicity similar to cortex

  • Dromedary hump

    • = subcapsular nodule = splenic bump

      Cause:	prolonged pressure by spleen during fetal development
      Location:	in mid portion of lateral border of left kidney

    • triangular contour + elongation of middle calyx

    • enhancement pattern like renal cortex

  • Hilar lip

    • = supra- / infrahilar bulge = medial part of kidney above / below sinus

    • Location:  most frequently medial to left kidney just above renal pelvis (on transaxial scan)

    • enhancement pattern like cortex with medulla

  • Fetal lobation

    • = persistent cortical lobation = ren lobatus

    • = 14 individual lobes with centrilobar cortex located around calices

  • Lobar dysmorphism

    • complete diminutive lobe situated deep within renal substance with its own diminutive calyx in its central portion = calyx of nonresorbed normal junctional parenchyma between upper + lower subkidneys

• ACQUIRED

  • Nodular compensatory hypertrophy

    • areas of unaffected tissue in the presence of focal renal scarring from chronic atrophic pyelonephritis (= reflux nephropathy), surgery, trauma, infarction;

    • hypertrophy usually evident within 2 months; less likely to occur > age 50

    • mass enhances identically to renal parenchyma

      DDx:	accessory spleen, medial lobule of spleen, splenosis, normal / abnormal bowel, pancreatic disease, gallbladder, adrenal abnormalities
      Dx:	static radionuclide imaging / renal arteriography / CT

Pseudokidney Sign

• = sonographic mass of reniform appearance with a central hyperechoic region surrounded by a hyperechoic region

• 1. Intussusception

• 2. Necrotizing enterocolitis

• 3. Midgut volvulus

• 4. Sigmoid volvulus

• 5. Crohn disease

• False-positive:

  • feces in colon, perforated Meckel diverticulum with malrotation + Ladd bands, psoas muscle, hematoma

Renal cystic disease

Potter Classification

• = POTTER SYNDROME

• = any renal condition associated with severe oligohydramnios

• peculiar facies with wide-set eyes, parrot-beak nose, pliable low-set ears, receding chin

  Type I:	infantile PCKD
  Type II:	multicystic dysplastic kidney disease, multilocular cystic nephroma
  IIa:	kidneys of normal / increased size
  IIb:	kidneys reduced in size
  Type III:	adult PCKD, tuberous sclerosis, medullary sponge kidney
  Type IV:	small cortical cysts / cystic dysplasia secondary to ureteropelvic junction obstruction

P.889

Renal Cystic Disease

• GENETIC CYSTIC DISEASE

  • Autosomal dominant polycystic kidney disease

  • Autosomal recessive polycystic kidney disease

  • Medullary sponge kidney

  • Medullary cystic disease

  • Glomerulocystic kidney disease

    • = congenital disease with extremely variable presentation + prognosis

    • Path: cysts within Bowman capsule tubular cysts

    • multiple macroscopic cortical cysts

• OBSTRUCTIVE CYSTIC DISEASE

  • Multicystic dysplastic kidney

  • Segmental / focal renal dysplasia

  • Familial renal dysplasia

• ACQUIRED CYSTIC DISEASE

  • Simple cyst

  • Parapelvic cyst

  • Acquired cystic disease of uremia

  • Infectious cysts (TB, Echinococcus, abscess)

  • Medullary necrosis

  • Pyelogenic cyst

• CYSTS ASSOCIATED WITH SYSTEMIC DISEASE

  • Tuberous sclerosis

  • von Hippel-Lindau disease

• CYSTIC TUMORS

  • Multilocular cystic nephroma

  • Cystic Wilms tumor

  • Cystic renal cell carcinoma

Syndromes with Multiple Cortical Renal Cysts

• Von Hippel-Lindau syndrome

• Tuberous sclerosis

• Meckel-Gruber syndrome

• Jeune syndrome

• Zellweger syndrome = cerebrohepatorenal syndrome

• Conradi syndrome = chondrodysplasia punctata

• Orofacialdigital syndrome

• Trisomy 13

• Turner syndrome

• Dandy-Walker malformation

Multiloculated Renal Mass

• NEOPLASTIC DISEASE

  • Cystic renal cell carcinoma

  • Multilocular cystic renal tumor

    • cystic nephroma

    • cystic partially differentiated nephroblastoma

  • Cystic Wilms tumor

  • Necrotic tumor

    • mesoblastic nephroma

    • clear cell sarcoma

• RENAL CYSTIC DISEASE

  • Localized renal cystic disease

  • Septated cyst

  • Multicystic dysplastic kidney

  • Segmental multicystic dysplasia

  • Complicated cyst

• INFLAMMATORY DISEASE

  • Echinococcus

  • Segmental XGP

  • Abscess

  • Malacoplakia

• VASCULAR LESIONS

  • AV fistula

  • Organizing hematoma

Abnormal nephrogram

Absence of Nephrogram

Global Absence of Nephrogram

• Pathophysiology: complete renal ischemia secondary to occlusion of main renal artery

• Injury to vascular pedicle during blunt abdominal trauma

• Thromboembolic disease

• Renal artery dissection: spontaneous, traumatic, iatrogenic

Segmental Absence of Nephrogram

• SPACE-OCCUPYING PROCESS

  • Neoplasm

  • Cyst

  • Abscess

• FOCAL RENAL INFARCTION

  • Arterial embolus / thrombosis

  • Vasculitis, collagen-vascular disease

  • Sickle cell anemia

  • Septic shock

  • Renal vein thrombosis

Rim Nephrogram

• = rim of cortex receiving collateral blood flow from capsular, peripelvic, and periureteric vessels

• Most specific indicator of renovascular compromise!

• 2 4-mm peripheral band of cortical opacification

• Cause:

  • Acute total main renal artery occlusion: seen in 50% of cases with renal infarction

  • Renal vein thrombosis

  • Acute tubular necrosis

  • 4. Severe chronic urinary obstruction

• DDx: severe hydronephrosis (rim / shell nephrogram surrounding dilated calices)

Unilateral Delayed Nephrogram

• OBSTRUCTIVE UROPATHY

• REDUCTION IN RENAL bloodflow

  • Renal artery stenosis

  • Renal vein thrombosis

Striated Nephrogram

• = streaky linear bands of alternating hyper- and hypoattenuation parallel to axis of tubules + collecting ducts during excretory phase

P.890

• Cause:

  • stasis of contrast material in dilated collecting ducts on background of edematous renal parenchyma (diminished concentration of contrast material in tubules from ischemia + tubular obstruction by inflammatory cells + debris)

• UNILATERAL

  • Acute ureteric obstruction

  • Acute bacterial nephritis / pyelonephritis

  • Renal contusion

  • Renal vein thrombosis

• BILATERAL

  • Acute pyelonephritis

  • Intratubular obstruction: Tamm-Horsfall proteinuria, rhabdomyolysis with myoglobinuria

  • Systemic hypotension

  • Autosomal recessive PCKD

  • Medullary sponge kidney

  • Medullary cystic disease

• mnemonic:  CHOIR BOY

  • Contusion

  • Hypotension (systemic)

  • Obstruction (ureteral)

  • Intratubular obstruction

  • Renal vein thrombosis

  • Bacterial nephritis (acute)

  • Obstruction (ureteral) it is so common!

  • Yes, also cystic diseases: infantile PCKD, medullary cystic disease, medullary sponge kidney

Persistent Nephrogram

• BILATERAL GLOBAL

  • Systemic hypotension

  • Intratubular obstruction from protein:

    • Tamm-Horsfall, Bence Jones, myoglobin

  • Tubular damage by contrast material

• UNILATERAL GLOBAL

  • Renal artery stenosis

  • Renal vein thrombosis

  • Urinary tract obstruction

• SEGMENTAL

  • Obstructed moiety of duplicated collecting system

  • Obstructing renal calculus

  • Obstructing neoplasm

  • Focal stricture

  • Focal parenchymal disease: tubulointerstitial infection

Abnormal Nephrogram due to Impaired Perfusion

• SYSTEMIC HYPOTENSIVE REACTION

  • as reaction to contrast material / cardiac failure / dehydration / shock

  • Pathophysiology:

    • drop in perfusion pressure after contrast reaches kidney leads to increased salt + water reabsorption and slowed tubular transit

  • prolonged bilateral dense nephrograms = persistent increasing nephrogram

  • decrease in renal size

  • loss of pyelogram after initial opacification

  • NUC (use of glomerular filtration agent [eg, Tc-99m DTPA] preferred)

    • prolonged cortical transit + reduced excretion

• RENAL ARTERY STENOSIS

  • decreased nephrographic opacity + rim nephrogram

  • hyperconcentration in collecting system

  • ureteral notching

  • NUC (glomerular filtration agent [eg, Tc-99m DTPA] preferred):

    • decreased perfusion with prolonged excretory phase

• IMPAIRED PERFUSION OF SMALL ARTERIES

  • Trueta shunting = transient rerouting of blood flow from cortex to medulla

  • Cause:

    • reflex spasm during arterial angiography secondary to catheter trauma / pressure injection of highly concentrated contrast medium

    • chronic renal disorders (collagen vascular disease, malignant nephrosclerosis, chronic glomerulonephritis)

    • necrotizing vasculitis (polyarteritis nodosa, scleroderma, hypertensive nephrosclerosis)

  • CT, Angio:

    • inhomogeneous opacification of cortex

    • spotted nephrogram

  • IVP:

    • irregular cortical nephrogram = spotted nephrogram (DDx: scleroderma, hypertensive nephrosclerosis)

• ACUTE VENOUS OUTFLOW OBSTRUCTION

  • in renal vein thrombosis

  • obstructive nephrogram

  • progressive increase in opacity of entire kidney

Abnormal Nephrogram due to Impaired Tubular Transit

• Cause:

  • EXTRARENAL: ureteric obstruction (eg, stone)

    • obstructive nephrogram

    • NUC:

      • before decrease in renal function use of glomerular filtration agent (eg, Tc-99m DTPA); with decrease in renal function use of plasma flow agents (eg, Tc-99m MAG3 / I-123 Hippuran) preferred

    • continuous increase in renal activity

    • dilatation of collecting system

  • INTRARENAL

    • (a) segmental: limb of duplication system, caliceal obstruction, interstitial edema

      • segmental nephrogram

    • (b) protein precipitation: Tamm-Horsfall protein (a normal mucoprotein product of proximal nephrons), Bence Jones protein (multiple myeloma), uric acid precipitation (acute urate nephropathy), myoglobulinuria, hyperproteinuric state

    • striated nephrogram

    • NUC:

      • before decrease in renal function use of glomerular filtration agent (eg, Tc-99m DTPA); with decrease in renal function use of plasma flow agents (eg, Tc-99m MAG3 / I-123 Hippuran) preferred

      P.891

      • prolonged cortical transit time + prolonged excretory phase

Abnormal Nephrogram due to Abnormal Tubular Function

Pathophysiology:

• PROXIMAL TUBULE

  • reabsorbs almost all of glucose, amino acids, phosphate, bicarbonate

  • glycosuria (Toni-Fanconi syndrome)

  • aminoaciduria (cystinuria)

  • phosphaturia (phosphate diabetes, thiazides)

  • HCO₃^- wasting (proximal renal tubular acidosis)

• DISTAL TUBULE

  • absorbs most of water

  • diabetes insipidus, secretes H⁺

  • distal renal tubular acidosis

• Acute tubular necrosis

  • immediate persistent nephrogram (common)

  • progressive increasing opacity (rare)

• Contrast-induced renal failure

Striated Angiographic Nephrogram

= random patchy densities reflecting redistribution of blood flow from the cortical vasculature to the vasa recta of the medulla

• Obliterative diseases of the renal microvasculature:

  • polyarteritis nodosa, scleroderma, necrotizing angitis, catheter-induced vasospasm

• Acute bacterial nephritis

• Renal vein thrombosis

Increasingly Dense Nephrogram

• = initially faint nephrogram becoming increasingly dense over hours to days

• Mechanism:

  • diminished plasma clearance of contrast material

  • leakage of contrast material into renal interstitial space

  • increase in tubular transit time

• Cause:

  • VASCULAR = diminished perfusion

    • Systemic arterial hypotension (bilateral)

    • Severe main renal artery stenosis (unilateral)

    • Acute tubular necrosis (in 33%):

      • due to contrast material nephrotoxicity

    • Acute renal vein thrombosis

  • INTRARENAL

    • Acute glomerular disease

  • COLLECTING SYSTEM

    • Intratubular obstruction

      • Uric acid crystals (acute urate nephropathy)

      • Precipitation of Bence Jones protein (myeloma nephropathy)

      • Tamm-Horsfall protein (severely dehydrated infants / children)

    • Acute extrarenal obstruction: ureteral calculus

Vicarious Contrast Material Excretion during IVP

• = biliary contrast material detected radiographically following intravenous administration of contrast material

• Normal contrast excretion:

  • <2% of urographic dose of diatrizoates + iothalamates are handled by hepatobiliary excretion

• Pathophysiology:

  • increase in protein binding due to prolonged intravascular contact + acidosis

• Cause:

  • Uremia (reduction in glomerular filtration + uremia-associated acidosis)

  • Acute unilateral obstruction (increase in circulation time + transient intracellular acidosis)

  • Spontaneous urinary extravasation (prolonged vascular contact of contrast material)

Collecting system

Spontaneous Urinary Contrast Extravasation

• = SPONTANEOUS pyelorenal BACKFLOW

• Etiology: physiologic safety valve for obstructed urinary tract with pressures of 80 100 mm Hg in collecting system due to ipsilateral ureteral obstruction from distal stone impaction; pressure is proportional to degree + duration of acute obstruction + dose of contrast material

• Incidence:  0.1 18%; M > F (male ureter less compliant)

• Criteria:

  • absence of recent ureteral instrumentation

  • absence of previous renal / ureteral surgery

  • absence of destructive urinary tract lesion

  • absence of external trauma

  • absence of external compression

  • absence of pressure necrosis due to stone

• Types:

  • Pyelotubular backflow

    • = opacification of terminal portions of collecting ducts (= papillary ducts = ducts of Bellini) as a physiologic phenomenon (in 13% with low osmolality + in 0.4% with high osmolality contrast media), wrongly termed backflow

    • wedge-shaped brushlike lines from calyx toward periphery

  • Pyelosinus backflow

    • = contrast extravasation from ruptured fornices along infundibula, renal pelvis, proximal ureter; most common form

    • Cx: urinoma, retroperitoneal fibrosis

  • Pyelointerstitial backflow

    • = contrast flow from pyramids into subcapsular tubules

  • Pyelolymphatic backflow

    • = contrast extravasation into periforniceal + peripelvic lymphatics

    • visualization of small lymphatics draining medially

  • Pyelovenous backflow

    • = forniceal rupture into interlobar / arcuate veins; rare

Widened Collecting System & Ureter

Fetal pyelectasis

P.892

• OBSTRUCTIVE UROPATHY

• NONOBSTRUCTIVE WIDENING

  • congenital

    • Megacalicosis

      • underdevelopment of papillae, usually unilateral

    • Congenital primary megaureter

      • = widened ureter with normally tapered distal end

    • Megacystis-megaureter syndrome

    • Prune-belly syndrome

    • Bardet-Biedl syndrome

    • Beckwith-Wiedemann syndrome

    • Megalourethra

  • increased urine volume

    • High-flow states: diabetes insipidus, osmotic diuresis, dehydrated patient undergoing rehydration, unilateral kidney

    • Vesicoureteral reflux

  • atony of renal collecting system

    • Infection: ie, acute pyelonephritis

    • Pregnancy

    • Retroperitoneal fibrosis

  • overdistended urinary bladder

  • previous long-standing significant obstruction:

    • dilatation remains in spite of relief of obstruction

Caliceal Abnormalities

• OPACIFICATION OF COLLECTING TUBULES

  • Pyelorenal backflow

  • Medullary sponge kidney

• PAPILLARY CAVITY

  • Papillary necrosis

  • Caliceal diverticulum

  • Tuberculosis / brucellosis

• LOCALIZED CALIECTASIS

  • Reflux nephropathy = chronic atrophic pyelonephritis

  • Compound calyx

  • Hydrocalyx

  • Congenital megacalyx

  • Localized postobstructive caliectasis

  • Localized tuberculosis / papillary necrosis

• GENERALIZED CALIECTASIS

  • Postobstructive atrophy

  • Congenital megacalices

  • Obstructive uropathy (hydronephrosis)

  • Nonobstructive hydronephrosis

  • Diabetes insipidus

Filling Defect in Collecting System

• mnemonic: 6 C's & 2 P's

  • Clot

  • Cancer

  • Cyst

  • Calculus

  • Candida + other fungi

  • Cystitis cystica

  • Polyp

  • Papilla (sloughed)

Nonopaque Intraluminal Mass in Collecting System

• NONOPAQUE CALCULUS

  • uric acid, xanthine, matrix

  • smooth, rounded, not attached

• TISSUE SLOUGH

  • Papillary necrosis

  • Cholesteatoma

  • Fungus ball = conglomeration of fibrillar hyphae

  • Inspissated debris ( mucopus )

• VASCULAR

  • 1. Blood clot: history of hematuria

  • change in appearance over time

• FOREIGN MATERIAL

  • Air from bladder via reverse peristalsis, direct trauma, renoalimentary fistula

  • Foreign matter

Mucosal Mass in Collecting System

• NEOPLASTIC

  • benign tumor

    • Aberrant papilla = papilla without calyx protruding into major infundibulum

    • Endometriosis

    • Fibroepithelial polyp = fibrous polyp

      • = fibroepithelioma = VASCULAR FIBROUS POLYP = POLYPOID FIBROMA

      • = mesodermal tumor with fibrovascular stroma + normal transitional cell epithelium

      • Age: 20 40 years

      • intermittent abdominal / flank pain

      • gross hematuria (rare)

      • elongated cylindrical filling defect with smooth margins

      • mobile on thin pedicle

  • malignant tumor

    • Uroepithelial tumors

      • Transitional cell carcinoma (85 91%)

      • Squamous cell carcinoma (10 15%)

        • Predisposing factors:

          • calculi (50 60%), chronic infection, leukoplakia, phenacetin abuse

          • infiltrating / superficially spreading

      • Mucinous adenocarcinoma

        • = metaplastic transformation

      • Sarcoma (extremely rare)

    • Metastases: breast (most common), melanoma, stomach, lung, cervix, colon, prostate

• INFLAMMATION / INFECTION

  • Tuberculosis

  • Candidiasis

  • Schistosomiasis

  • Pyeloureteritis cystica

  • Leukoplakia

  • Malacoplakia

  • Xanthogranulomatous pyelonephritis

• VASCULAR

  • submucosal hemorrhage

    • 1. Trauma

    • 2. Anticoagulant therapy

    • 3. Acquired circulating anticoagulants

    • 4. Complication of crystalluria / microlithiasis

    • thumbprinting with progressive improvement

  • vascular notching

    • Ureteropelvic varices

    P.893

    • Renal vein occlusion

    • IVC occlusion

    • Vascular malformation

    • Retroaortic left renal vein

    • Nutcracker effect on left renal vein between aorta and SMA

    • Polyarteritis nodosa

• PROMINENT MUCOSAL FOLDS

  • Redundant longitudinal mucosal folds of intermittent hydronephrosis (UPJ obstruction, vesicoureteral reflux) or after relief of obstruction

  • Chemical / mechanical irritation

  • Urticaria (Stevens-Johnson syndrome = erythema multiforme bullosa)

  • Leukoplakia (= squamous metaplasia)

  • Ureteral diverticulosis = rupture of the roofs of cysts in ureteritis cystica

Effaced Collecting System

• EXTRINSIC COMPRESSION

  • Unilateral / bilateral global enlargement of renal parenchyma

  • Renal sinus masses

    • Hemorrhage

    • Parapelvic cyst

    • Sinus lipomatosis

• SPASM / INFLAMMATION

  • infection

    • Acute pyelonephritis

    • Acute bacterial nephritis

    • Acute tuberculosis

  • Hematuria

• INFILTRATION

  • Malignant uroepithelial tumors

• OLIGURIA

  • Antidiuretic state

  • Renal ischemia

  • Oliguric renal failure

Renal calcification

Retroperitoneal Calcification

• NEOPLASM

  • Wilms tumor (in 10%)

  • Neuroblastoma (in 50%): fine granular / stippled / amorphous

  • Teratoma: cartilage / bone / teeth, pseudodigits, pseudolimbs

  • Cavernous hemangioma: phleboliths

• INFECTION

  • Tuberculous psoas abscess

  • Hydatid cyst

  • Alkaline-encrusted cystitis and pyelitis

• TRAUMA

  • Old hematoma

Nephrocalcinosis

• = NEPHROLITHIASIS

• = deposition of calcium salts in renal parenchyma

• Incidence:  0.1 6%; M > F

• Cause:  mnemonic:  MARCH

  • Medullary sponge kidney

  • Alkali excess

  • Renal medullary / cortical necrosis, RTA

  • Chronic glomerulonephritis

  • Hyperoxaluria, Hypercalcemia, Hypercalciuria

Medullary Nephrocalcinosis

• = calcifications involving the distal convoluted tubules in the loops of Henle

• Incidence:  95% of all nephrocalcinoses

• Cause:

  • HYPERCALCIURIA

    • endocrine

      • Hyperparathyroidism in 5% (primary >> secondary)

      • Paraneoplastic syndrome of lung + kidney primary (ectopic parathormone production)

      • Cushing syndrome

      • Diabetes insipidus

      • Hyperthyroidism / hypothyroidism

    • alimentary

      • Milk-alkali syndrome (excess calcium + alkali = milk + antacids)

      • Hypervitaminosis D

      • Beryllium poisoning

    • osseous

      • Osseous metastases, multiple myeloma

      • Prolonged immobilization

      • Progressive senile osteoporosis

    • renal

      • Medullary sponge kidney

      • Renal tubular acidosis (in 73% of primary RTA)

      • Bartter syndrome

        • tubular disorder with potassium + sodium wasting, hyperplasia of juxtaglomerular apparatus, hyperaldosteronism, hypokalemic alkalosis, and normal blood pressure

    • drug therapy

      • Furosemide (in infants)

      • Prolonged ACTH therapy

      • Vitamin E (orally)

      • Vitamin D excess

      • Calcium (orally)

      • Nephrotoxic drugs: outdated tetracycline, amphotericin B

    • miscellaneous

      • Sarcoidosis

      • Idiopathic hypercalciuria

      • Idiopathic hypercalcemia

  • HYPEROXALURIA = OXALOSIS

    • Primary hyperoxaluria

      • = Hereditary hyperoxaluria (more common)

      • = rare autosomal recessive inherited enzyme deficiency of carboligase with diffuse oxalate deposition in kidneys, heart, blood vessels, lung, spleen, bone marrow

      • Type I   =    -ketoglutarate-glyoxylate carboxylase deficiency

        • glycolic aciduria

      P.894

      • Type II   =   D-glycerate dehydrogenase deficiency

        • 1-glyceric aciduria

        • Age:  usually <5 years

        • Prognosis:  early death in childhood

    • Secondary hyperoxaluria

      • = enteric hyperoxaluria (rare)

      • Cause:  disturbance of bile acid metabolism after jejunoileal bypass, ileal resection, blind loop syndrome, Crohn disease, increased ingestion (green leafy vegetables), pyridoxine deficiency, ethylene glycol poisoning, methoxyflurane anesthesia

  • hyperuricosuria

    • Gouty kidney

    • Lesch-Nyhan syndrome

  • URINARY STASIS

    • Milk-of-calcium in pyelocaliceal diverticulum

    • Medullary sponge kidney

  • DYSTROPHIC CALCIFICATION

    • Renal papillary necrosis (especially analgesic nephropathy)

    • Chronic pyelonephritis

    • Sickle cell disease

    • Renal tuberculosis

      • mnemonic:  HAM HOP

        • Hyperparathyroidism

        • Acidosis (renal tubular)

        • Medullary sponge kidney

        • Hypercalcemia / hypercalciuria (sarcoidosis, milk-alkali syndrome, hypervitaminosis D)

        • Oxalosis

        • Papillary necrosis

• normal-sized / occasionally enlarged kidneys (medullary sponge kidney)

• small poorly defined / large coarse granular calcifications in renal pyramids:

  • uniform deposition: hyperparathyroidism / distal renal tubular acidosis (type 1)

  • asymmetric deposition in dilated collecting ducts within papillary tips: medullary sponge kidney

• US:

  • absence of hypoechoic papillary structures (earliest sign)

  • hyperechoic rim at corticomedullary junction + around tip and sides of pyramids

  • solitary focus of hyperechogenicity at tip of pyramid near fornix

  • increased echogenicity of renal pyramids shadowing (no acoustic shadowing with small + light calcifications)

• DDx of hyperechoic medulla in newborns:

  • oliguria with transient tubular blockage by Tamm-Horsfall proteinuria

• Cx: often followed by urolithiasis

Cortical Nephrocalcinosis

• = calcium deposition in renal cortex

• Incidence:  5% of all nephrocalcinoses

• Cause:

  • Acute cortical necrosis

  • Chronic glomerulonephritis

  • Alport syndrome = hereditary nephritis + deafness

  • Congenital oxalosis, primary hyperoxaluria

  • Chronic paraneoplastic hypercalcemia

  • Toxic: ethylene glycol, methoxyflurane

  • Sickle cell disease

  • Rejected renal transplant

    • mnemonic:  COAG

      • Cortical necrosis (acute)

      • Oxalosis

      • Alport syndrome

      • Glomerulonephritis (chronic)

• thin rim of calcification with a tramline appearance

• spotty appearance (= preferential deposition in necrotic glomeruli)

• US:

  • homogeneously increased echogenicity of renal parenchyma > liver echogenicity

Renovascular Disease

Renal Artery Aneurysm

• Prevalence: 0.01 0.1%; 22% of visceral aneurysms

• Types:

  • saccular (most common): near first bifurcation of main renal artery; congenital; associated with medial fibroplasia + atherosclerosis

  • fusiform: in medial fibroplasia; not calcified

  • dissecting: traumatic, spontaneous (atherosclerosis, intimal fibroplasia, perimedial fibroplasia), iatrogenic

• Cx:

  • Hypertension (unusual)

  • Perinephric / retroperitoneal hemorrhage [rare] with increased risk in peripartum women

  • Formation of AV fistula

  • Peripheral renal embolization [from mural thrombus]

  • Thrombosis

  • Hematuria

Extrarenal Aneurysm (2/3)

• True aneurysm

  • Atherosclerotic (most common)

  • Fibromuscular dysplasia

  • Pregnancy

  • Mesenchymal disease: neurofibromatosis, Ehlers-Danlos syndrome

• False aneurysm

  • Trauma; renal artery angioplasty

  • Beh et disease

  • Mycotic aneurysm

    • 2.5% of all aneurysms

    • Cause:  bacteremia, SBE, perivascular extension of inflammation

    • Organism:  Streptococcus, Staphylococcus, Pneumococcus, Salmonella

• incomplete / complete ring of calcification

• variable enhancement (depending on amount of thrombus)

• Rx:

  • conservative in asymptomatic patient for well-calcified aneurysm <2 cm in diameter

  P.895

  • surgery for (a) interval growth, (b) emboli to kidney, (c) in woman of childbearing age, (d) diminished renal function / ischemia / hypertension / dissection

Intrarenal Aneurysm (1/3)

in interlobar and more peripheral branches

• CONGENITAL (most common)

  • Congenital renal aneurysm

    • Age at Dx: 30 years or older; M:F = 1:1

    • hypertension in 25% (from segmental renal ischemia)

    • saccular aneurysm close to vascular bifurcations, may calcify

    • often bilateral

    • Rx: surgical / endovascular repair for aneurysm >1.0 cm in hypertensive patient / for aneurysm >1.5 cm in asymptomatic normotensive patient

• ARTERITIS

  • Polyarteritis nodosa

  • SLE

  • Allergic vasculitis

  • Wegener granulomatosis

  • Transplant rejection

  • Drug-abuse vasculitis

    • Kidney most commonly affected organ

    • Cause:

      • immunologic injury from circulating hepatitis antigen-antibody complexes producing a necrotizing angitis

      • bacterial endocarditis

      • drug-related

      • impurity-related

    • Drugs:  methamphetamine, heroin, LSD

    • multiple small aneurysms in interlobar branches near corticomedullary junction

    • inhomogeneous spotty nephrogram

• DEGENERATIVE: Atherosclerosis (may calcify)

• TUMOR

  • Neoplasm (RCC in 14%; adult Wilms tumor)

  • Hamartoma (angiomyolipoma in 50%)

  • Metastatic arterial myxoma

  • Vascular malformation

• MESENCHYMAL DISEASE:

  • Neurofibromatosis

  • Fibroplasia

• TRAUMA

• INFECTION: syphilis, tuberculosis

Spontaneous Retroperitoneal Hemorrhage

• RENAL TUMOR (57 63%)

  • malignant tumor (30 33%)

    • RCC (33%)

    • TCC of renal pelvis

    • Wilms tumor

    • Lipo-, fibro-, angiosarcoma

  • benign tumor (24 33%):

    • Angiomyolipoma (16 24%)

    • Lipoma

    • Adenoma

    • Fibromyoma

    • Ruptured hemorrhagic cyst

• VASCULAR DISEASE (18 26%)

  • Ruptured renal artery aneurysm

  • Vasculitis (eg, polyarteritis nodosa in 13%)

  • Arteriovenous malformation

  • Segmental renal infarction

• INFLAMMATION / INFECTION (7 10%)

  • Abscess (in 50% of infections)

  • Acute / chronic nephritis

• COAGULOPATHY

  • Anticoagulant therapy (in 4.3 6.6% of IV heparin, in 01. 0.6% of oral anticoagulants)

    • Source:  idiopathic (42%), tumor (21%), stone disease (17%), hemorrhagic cystitis

  • Bleeding diathesis

  • Long-term hemodialysis

• PRIMARY ADRENAL CYST / TUMOR

  • Pheochromocytoma

    • Massive bleed due to an undiagnosed pheochromocytoma has been lethal in 50%!

  • Pseudocyst

  • Myelolipoma

  • Hemangioma

  • Adrenocortical adenoma / carcinoma

  • Metastasis

• flank pain of sudden onset

• Follow-up CT may be indicated at 3 and 6 months if the source of blood remains indeterminate!

• Surgical exploration must be considered to uncover a small renal tumor if the cause of hemorrhage is not determined radiologically!

Subcapsular Hematoma

• subcapsular mass with flattening of renal parenchyma

• total resorption / formation of pseudocapsule with calcification

• Angio:

  • avascular mass

• Cx: Page kidney (ischemia, release of renin, HTN)

Renal Doppler

• NORMAL RENAL DOPPLER

  • resistive index (RI) of 0.70 = upper limit of normal

  • Elevation of RI:

    • significant systemic hypotension

    • markedly decreased heart rate

    • perinephric / subcapsular fluid collection

    • in neonates + infants

• RENAL MEDICAL DISEASE

  • Elevation of RI more likely with vascular / tubulointerstitial process, less likely with glomerular disease

  • May be useful in predicting clinical outcome in:

    • hemolytic-uremic syndrome

    • acute renal failure

    • nonazotemic patients with severe liver disease

• RENAL ARTERY STENOSIS

• RENAL VEIN THROMBOSIS

P.896

Ureter

Ureteral Deviation

• LUMBAR URETER

  • lateral deviation (common)

    • Hypertrophy of psoas muscle

    • Enlargement of paracaval / paraaortic lymph nodes

    • Aneurysmal dilatation of aorta

    • Neurogenic tumors

    • Fluid collections (abscess, urinoma, lymphocele, hematoma)

  • medial deviation

    • Retrocaval ureter (on right side only)

    • Retroperitoneal fibrosis

• PELVIC URETER

  • medial deviation

    • Hypertrophy of iliopsoas muscle

    • Enlargement of iliac lymph nodes

    • Aneurysmal dilatation of iliac vessels

    • Bladder diverticulum at UVJ (Hutch)

    • Following abdominoperineal surgery + retroperitoneal lymph node dissection

    • Pelvic lipomatosis

  • lateral deviation with extrinsic compression

    • Pelvic mass (eg, fibroids, ovarian tumor)

Ureteral Dilatation

Size of ureter:  >3 mm

• OBSTRUCTION

  • Ureterolithiasis

• CONGENITAL

  • Chronic vesicoureteral reflux

  • Posterior urethral valves

  • Megaureter

  • Prune-belly syndrome

• INFECTION / INFLAMMATION

  • impairing ureteral peristalsis

  • 1. UTI (eg, E. coli, Pseudomonas, Citrobacter)

  • 2. Appendicitis

  • 3. Diverticulitis

• COMPRESSION

  • by pelvic / abdominal mass

Megaureter

• VESICOURETERAL REFLUX

  • primary vesicoureteral reflux

    • Primary reflux megaureter

      • Cause: abnormal ureteral tunnel at UVJ

    • Prune belly syndrome

  • secondary vesicoureteral reflux

    • Hypertonic neurogenic bladder

    • Bladder outlet obstruction

    • Posterior urethral valves

• OBSTRUCTION

  • primary obstruction

    • Intrinsic ureteral obstruction (stone, stricture, tumor)

    • Ectopic ureter

    • Ureterocele

    • Ureteral duplication

      • tortuous dilated ureter of upper moiety

  • secondary obstruction

    • Retroperitoneal obstruction: tumor, fibrosis, aortic aneurysm

    • Bladder wall mass

    • Bladder outlet obstruction: eg, prostatic enlargement

• NONREFLUX-NONOBSTRUCTED MEGAURETER

  • Congenital primary megaureter = megaloureter

  • Polyuria: eg, diabetes insipidus, acute diuresis

  • Infection

  • Ureter remaining wide after relief of obstruction

• mnemonic:  DiaPOUR

  • Diabetes insipidus

  • Primary megaureter

  • Obstruction (recent / old)

  • UVJ obstruction

  • Reflux

Ureteral Stricture

• INTRINSIC CAUSE

  • mucosal

    • Primary ureteral tumors

  • mural

    • Endometriosis

      • common disorder in menstruating women (15%); ureteral involvement is rare and indicates widespread pelvic disease

      • abrupt smooth stricture of 0.5 2.5 cm length

      • rectosigmoid involvement on BE

    • Tuberculosis, schistosomiasis

    • Traumatic

      • ureterolithotomy, endoscopic stone extraction, hysterectomy

    • Amyloidosis

      • distal stricture with submucosal calcification

    • Nonspecific (rare)

• EXTRINSIC CAUSE

  • Endometriosis

    • extrinsic form:intrinsic form = 4:1

  • Abscess

    • tuboovarian, appendiceal, perisigmoidal

  • Inflammatory bowel disease

    • (eg, Crohn disease, diverticulitis)

  • Radiation fibrosis

  • Metastases

    • cervix, endometrium, ovary, rectum, prostate, breast, lymphoma

  • Iliac artery aneurysm (with perianeurysmal fibrosis)

• mnemonic:  MISTER

  • Metastasis (extrinsic / intrinsic)

  • Inflammation from calculus

  • Schistosomiasis

  • Tuberculosis, Transitional cell carcinoma, Trauma

  • Endometriosis + other periureteral inflammatory process

  • Radiation therapy, Retroperitoneal fibrosis

Ureteral Filling Defect

• FIXED

  • neoplasm

    P.897

    • Urothelial neoplasm

    • Metastasis

    • Fibroepithelial polyp

  • inflammation

    • Ureteritis cystica

    • Tuberculosis

    • Endometriosis

• MOBILE

  • Calculus

  • Sloughed papilla

  • Blood clot

Ureteral Calcification

• URETERAL LUMEN

  • Stone migrated from kidney

  • Stone in ureteral diverticulum / ureterocele

  • Steinstrasse (stone street) = collection of stone fragments in distal ureter following lithotripsy

• URETERAL WALL

  • Schistosomiasis

  • Tuberculosis

  • Amyloid infiltration

  • Ureteral tumor

• DDx:

  • Phlebolith in gonadal vein (multiple, not along course of ureter, centrally radiolucent)

  • Orally administered contrast material trapped in appendix / diverticulum

  • Dermoid cyst with calcification

  • Silastic fallopian tube band

  • Radiation seeds used for prostate cancer

Urinary Bladder

Bilateral Narrowing of Urinary Bladder

• WITH ELEVATION OF BLADDER FLOOR

  • Pelvic lipomatosis

  • Pelvic hematoma

    • Cause:  trauma, anticoagulant therapy, spontaneous rupture of blood vessels, blood dyscrasia (rare), bleeding neoplasm (rare)

  • 3. Chronic cystitis

• WITH SUPERIOR COMPRESSION OF BLADDER

  • Thrombosis of IVC

    • Cause:  trauma, hypercoagulability state (oral contraceptives), extension of thrombi from lower extremity, abdominal sepsis, Budd-Chiari syndrome, compression of IVC by neoplasm

    • collaterals through gonadal veins, ascending lumbar veins, vertebral plexus, retroperitoneal veins, portal vein (via hemorrhoidal veins)

    • notching of distal ureter by ureteral veins

  • Pelvic lymphadenopathy

    • Cause:  lymphoma (most often), prostatic carcinoma

    • polycyclic asymmetric compression of bladder

    • medial displacement of pelvic segment of ureters

    • lateral displacement of upper ureters

  • Hypertrophy of iliopsoas muscles

  • Bilateral pelvic masses

    • bilateral lymphocysts (following radical pelvic surgery)

    • bilateral urinomas

    • bilateral pelvic abscesses

  • Retroperitoneal fibrosis

  • Large iliac artery aneurysms

Inverted Pear-shaped Urinary Bladder

• mnemonic:  HALL

  • Hematoma

  • Aneurysm (bilateral common / external iliac artery)

  • Lipomatosis, pelvic

  • Lymphadenopathy (pelvic)

Small Bladder Capacity

• Cause:

  • Thickened / fibrotic bladder wall

    • Interstitial cystitis

    • Tuberculous cystitis

    • Cystitis cystica

    • Schistosomiasis

    • Trauma: surgical resection, radiation therapy

  • Disuse of bladder

• urinary frequency

• progressive rise in bladder pressure during filling

• reduced bladder compliance

• thickened bladder wall + decreased bladder volume

• vesicoureteral reflux

Bladder Wall Thickening

• Normal bladder wall thickness (regardless of age + gender):

  • <5 mm   in nondistended bladders

  • <3 mm   in well-distended bladders

• TUMOR

  • Neurofibromatosis

• INFECTION / INFLAMMATION

  • Cystitis

• MUSCULAR HYPERTROPHY

  • Neurogenic bladder

  • Bladder outlet obstruction (eg, posterior urethral valves)

• UNDERDISTENDED BLADDER

Urinary Bladder Wall Masses

• CONGENITAL

  • Congenital septum

  • Simple ureterocele

  • Ectopic ureterocele

• BLADDER TUMORS

• INFLAMMATION / INFECTION

  • Cystitis: hemorrhagic cystitis, abacterial cystitis, bullous cystitis, edematous cystitis, interstitial cystitis, eosinophilic cystitis, granulomatous cystitis, emphysematous cystitis, cystitis cystica, cyclophosphamide cystitis, cystitis glandularis (premalignant lesion with villous lesions in bladder dome from proliferation of intestinelike glands in submucosa)

  • Tuberculosis

  • Schistosomiasis

  • Malacoplakia

  P.898

  • Extravesical inflammation:

    • Diverticulitis

    • Crohn disease

    • endometriosis

• HEMATOMA

  • after instrumentation, surgery, trauma

Bladder Tumor

• Incidence:  2 6% of all tumors

• EPITHELIAL TUMORS (95%)

  • Urothelial carcinoma = transitional cell carcinoma (90%)

  • Squamous cell carcinoma (4% in USA)

    • worst prognosis; secondary to chronic disorders (chronic irritation from indwelling catheters, infection, stricture, calculi), cyclophosphamide, smoking, intravesical bacillus Calmette-Gu rin, bladder diverticula, schistosomiasis (>50% of bladder tumors in contries with endemic bilharziasis)

  • Adenocarcinoma (1%)

    • most common in bladder exstrophy, less common in cystitis glandularis + urachal carcinoma (at dome of bladder in urachal remnant)

    • metastatic adenocarcinoma (colon, prostate, rectum) more common than primary

  • Small cell / neurondocrine carcinoma (<0.5%)

    • = highly aggressive tumor with invasive disease in 94% at presentation

    • Age:  20 91 years; M:F = 3 5:1

    • ematuria (88%)

    • large polypoid / nodular tumor

    • size from 3 to 8 cm

    • Prognosis: 16% 5-year survival rate

  • Carcinoid

    • Mean size:  6 mm

  • Melanoma (extremely rare)

• NONEPITHELIAL / mesenchymal TUMORS

  • primary benign tumors from

    • muscle

      • Leiomyoma (0.43%)

        • Most common nonepithelial tumor

        • Age: 22 78 years; M:F = 1:1

        • hematuria secondary to ulceration

        • Location: arise in submucosa

        • Site: submucosal (7%) / intravesical (63%) / extravesical (30%)

        • solid homogeneous mass

        • smooth indentation of bladder wall

        • intraluminal mass degeneration

      • Rhabdomyoma (rare)

    • nerve

      • Neurofibroma / NF 1 in 60%

        • typically low in attenuation on CT

        • hypointense mass on T1WI

        • target sign on T2WI for plexiform neurofibroma = central hypointense fibrosis surrounded by hyperintense myxoid stroma

      • Paraganglioma = pheochromocytoma (0.1%)

        • 1% of all pheochromocytomas

        • Age: 10 78 years; M < F

        • Origin: from paraganglia of bladder wall

        • adrenergic attack at micturition ( micturition attack ) / bladder filling (headaches, weakness) in 50%

        • intermittent hypertension

        • elevated catecholamine levels

        • submucosal mass

        • ring calcification around circumference

        • marked enhancement (KEY FEATURE)

        • N.B.: biopsy may incite hypertensive crisis!

        • Prognosis: 7% are malignant

    • fat

      • Lipoma

    • fibrous tissue

      • Fibroma

      • Solitary fibrous tumor

    • blood vessels

      • Hemangioma

        • Age: 50% during childhood; 58 (range, 19 76) years during adulthood

        • median size of 7 mm (range, 2 30 mm)

      • Plasmacytoma

      • Nephrogenic adenoma

        • Associated with: cystitis cystica / cystitis glandularis

  • primary malignant tumors

    • Primary lymphoma

      • 2nd most common nonepithelial tumor of urinary bladder

      • Age: 40 years; M:F = 1:3

      • Histo: low-grade B-cell mucosa-associated lymphoid tissue (MALT) / diffuse large B-cell type

      • Location: submucosal; at bladder base + trigone

    • Rhabdomyosarcoma

      • Age: 1st and 2nd decades of life

      • Most common bladder tumor in patients <10 years of age

    • Leiomyosarcoma

      • Most common nonepithelial malignant bladder tumor

      • Age: mainly >40 (range, 25 88) years; M:F = 3:1

      • Location: rarely at trigone

      • poorly circumscribed invasive mass

      • heterogeneous texture from necrosis (common)

      • mean size of 7 cm

    • Osteosarcoma

  • secondary tumors

    • Metastases

      • 1.5% of all bladder malignancies

      • Origin: melanoma > stomach > breast > kidney > lung

      • solitary / multiple nodules

    • Lymphoma

      • bladder involved at autopsy: in 15% of NHL, in 5% of Hodgkin disease

    • Leukemia

      • microscopic involvement in 22% at autopsy

    • Direct extension (common)

      P.899

      • from prostate, rectum, sigmoid, cervix, ovary

    • Endometriosis

      • Location: on posterior wall

      • urinary symptoms in 80%

Bladder Calcification

Bladder Calculi

• Stasis calculi (70%)

  • in bladder outflow obstruction, bladder diverticula, cystocele, neuropathic bladder dysfunction

  • Associated with:  gram-negative lower urinary tract infection (in 30%), in particular Proteus

• Migrant calculi

  • = renal calculi spontaneously passing into bladder

• Foreign body nidus calculi

  • from self-introduced objects, urinary stent, chronic catheterization, bladder wall-penetrating bone fragments, prostatic chips, nonabsorbable suture material, fragments of Foley balloon catheter, pubic hair, presence of intestinal mucosa (in bladder augmentation, ileal conduit, repaired bladder exstrophy)

• Idiopathic/ primary/ endemic calculi

  • Countries: in North Africa, India, Indonesia

  • Age: in young boys of low socioeconomic class (nutritional deficiency?)

• Incidence: India (13:100,000); less common in western hemisphere

• Number of stones: solitary (86%); multiple (in up to 25%)

• Composition: magnesium ammonium phosphate (50%), calcium salts (31%), uric acid origin (5%)

• hematuria, recurrent UTIs, pelvic pain, irritative / obstructive voiding symptoms

• Rx: surgical extraction, lithotripsy, alkalinization of urine

• Rate of recurrence: 41%

Bladder Wall Calcification

• INFLAMMATION

  • Schistosomiasis (50%)

    • relatively normal distensibility of bladder

    • thin arcuate pattern of calcification

  • Tuberculosis

    • bladder markedly contracted

  • Cystitis:

    • postirradiation cystitis, alkaline incrusted cystitis, cytotoxin cystitis

  • Bacillary UTI (extremely uncommon)

  • Encrusted foreign material

  • Alkaline-encrusted cystitis and pyelitis

• NEOPLASM

  • Primary neoplasm of bladder: TCC, squamous cell carcinoma, leiomyosarcoma, hemangioma, neuroblastoma, osteogenic sarcoma

  • Urachal carcinoma

• mnemonic:  SCRITT

  • Schistosomiasis

  • Cytoxan

  • Radiation

  • Interstitial cystitis

  • Tuberculosis

  • Transitional cell carcinoma

Masses Extrinsic to Urinary Bladder

• NORMAL / ENLARGED ORGANS

  • Uterus, leiomyomatous uterus, pregnant uterus

  • Distended rectosigmoid

  • Ectopic pelvic kidney

  • Prostate cancer / BPH

• SOLID PELVIC TUMORS

  • Lymphadenopathy

  • Bone tumor from sacrum / coccyx

  • Rectosigmoid mass

  • Hip arthroplasty

  • Neurogenic neoplasm, meningomyelocele

  • Pelvic lipomatosis / liposarcoma

• CYSTIC PELVIC LESIONS

  • congenital / developmental

    • Urachal cyst

    • M llerian duct cyst

    • Gartner duct cyst

    • Anterior meningocele

    • Hydrometrocolpos

  • related to trauma

    • Hematoma (eg, rectus sheath hematoma)

    • Urinoma

    • Lymphocele

    • Abscess

    • Aneurysm

    • Mesenteric cyst

  • cyst of genitalia

    • Prostatic cyst

    • Cyst of seminal vesicle

    • Cyst of vas deferens

    • Ovarian cyst

    • Hydrosalpinx

    • Vaginal cyst

  • cyst of urinary bladder

    • Bladder diverticulum

  • cyst of GI tract

    • Peritoneal inclusion cyst

    • Fluid-filled bowel

Voiding Dysfunction

• FAILURE TO STORE URINE

  • urinary frequency, urgency, incontinence

  • bladder causes

    • involuntary detrusor contractions

      • detrusor instability (idiopathic / neurogenic)

      • detrusor hyperreflexia (upper cord lesion)

    • poor bladder compliance

      • detrusor hyperreflexia

      • bladder wall fibrosis

    • sensory urgency

      • infection, inflammation, irritation

      • neoplasia

    • vesicovaginal fistula

    • psychogenic condition

  P.900

  • sphincter causes

    • Stress incontinence

    • Sphincteric incontinence

  • extravesical ectopic insertion of ureter in females

• FAILURE TO EMPTY BLADDER

  • poor flow, straining, hesitancy

  • inability to completely empty bladder

  • bladder causes

    • Detrusor areflexia (sacral arc lesion)

    • Impaired detrusor contractility (myogenic)

    • Psychogenic condition

  • bladder outlet obstruction:

    • Bladder neck contracture

    • Prostatic enlargement

    • Detrusor-external sphincter dyssynergia

    • Scarring from surgery / radiation therapy

    • Ectopic ureterocele

    • Urethral stenosis

    • Urethral kinking (eg, due to cystocele)

Incontinence

• Stress incontinence

• Vesicovaginal / ureterovaginal fistula

• Urge incontinence

• Psychogenic incontinence

• Overflow incontinence

  • secondary to lesions of sacral spinal cord / sacral reflex arc or severe outlet obstruction

• Reflex voiding

  • hyperreflexive lesion (lesion of upper spinal cord)

  • uninhibited / unstable bladder

• Continual dribbling

  • = extravesical ectopic termination of ureter

Stress Incontinence

• = SPHINCTER WEAKNESS INCONTINENCE

• Cause:

  • Male: S/P prostatectomy with damage to distal sphincter

  • Female: congenital bladder neck weakness, pregnancy, childbirth, aging (secondary to changes in anatomic relationship of urethra + bladder base)

• frequency, urgency (involuntary filling of bladder neck)

• opening of bladder neck during coughing

• impairment of milk-back mechanism (= retrograde emptying of urethra during interruption of voiding phase does not occur)

• urethrovesical descent (in types I + II)

• Chain cystography:

  • posterior urethrovesical angle (= angle between posterior urethra + bladder base) increased >100

  • upper urethral axis (= angle between upper urethra + vertical line) increased >35

Detrusor Instability

• = MOTOR URGE INCONTINENCE = UNSTABLE BLADDER

• Condition resembles that of immature bladder before toilet training

• Patient groups:

  • symptoms of nocturnal enuresis + frequency / incontinence dating back to childhood

  • idiopathic instability occurring in middle age

  • outflow obstruction commonly in men

  • degenerative instability secondary to cardiovascular + neurologic disease later in life

• frequency, urgency, urge incontinence, occasionally nocturia

• hesitancy + difficulty in voiding may occur in men without significant prostatic hypertrophy

• involuntary bladder contractions with no relationship to bladder distension

• progressively vigorous contractions during bladder filling

• postural instability limited to upright position

• impaired milk-back mechanism due to high bladder pressure

• strong after contractions following bladder emptying

• Cx: thickening of bladder wall, bladder diverticula

• Rx: treatment of obstruction, anticholinergic drug (oxybutynin), operative increase in bladder capacity

Sensitive Bladder (Sensory Urgency)

• Cause: cystitis (reduced compliance), some cases of stress incontinence (filling of bladder neck induces urgency)

• frequency, urgency, sometimes nocturia

• patient uncomfortable with low bladder filling

• no abnormal rise in bladder pressure

• normal voiding function

Detrusor-sphincter Dyssynergia

• = overactivity of bladder neck muscle with failure to relax at beginning of voiding

• Cause: spinal cord lesion / trauma above level of sacral outflow

• difficulty in voiding frequency

• lifelong history of poor stream

• collarlike indentation of bladder neck during voiding (= persistent / intermittent narrowing of membranous urethra)

• may have high voiding pressure + reduced flow

• trapping of contrast in urethra during interruption of flow

• massive reflux into prostatic ducts during voiding (due to high pressure within prostatic urethra)

• severely trabeculated Christmas-tree bladder + bilateral hydroureteronephrosis

• Rx: bladder neck incision

Hinman Syndrome

• = nonneurogenic NEUROGENIC BLADDER [NNNB] = DETRUSOR-SPHINCTER DYSSYNERGIA

• Cause: no neurologic / anatomic obstructive disease; distinctly abnormal family dynamics (in 50%)

• Age: some time after toilet training with onset during early / late childhood / puberty

• clinical criteria:

  • intact perineal sensation + anal tone

  • normal anatomy + function of lower extremities

  • absence of skin lesions overlying sacrum

  • normal lumbosacral spine at plain radiography

  • normal spinal cord at MR imaging

• high-pressure uninhibited detrusor contractions

P.901

• lack of coordination between detrusor contraction + periurethral striated sphincter relaxation

• inability to suppress bladder contractions

• normal response of detrusor muscle to reflex stimulation

• increased bladder capacity + pressure

• sphincter activity may increase paradoxically during detrusor contraction

• US:

  • trabeculated bladder

  • dilatation of upper urinary tracts

  • renal damage

• VCUG:

  • urethra normal during early voiding

  • urethral distension after contraction of external sphincter as voiding progresses

  • ureterovesical obstruction / reflux

• Rx: suggestion therapy + hypnosis, bladder retraining, biofeedback, anticholinergic drugs

Wetting

• Enuresis

  • = manifestation of neuromuscular vesicourethral immaturity; M:F = 3:2

  • intermittent wetting, usually at night during sleep

  • often positive history of enuresis from one parent

  • normal physical examination

  • no structural abnormality; urography NOT indicated

• Epispadia

• Sacral agenesis

  • = segmental defect (below S2) with deficiency of nerves that innervate bladder, urethra, rectum, feet

  • Children of diabetic mothers are affected in 17%!

• Extravesical infrasphincteric ectopic ureter

  • only affects girls as boys do NOT have infrasphincteric ureteral orifices

  • ureter draining upper pole of duplex system exits below urethral sphincter (90%)

  • ureter draining single system with ectopic extravesical orifice (10%)

• Synechia vulvae

  • = adhesive fusion of minor labia directs urine primarily into vagina from where it dribbles out post micturition

• Vaginal reflux

  • in obese older girls with fat thighs and fat labia

• Miscellaneous

  • posterior urethral valves, urethral stricture, urethral diverticula

Prostatic Obstruction

• = urethral compression by hypertrophic prostatic tissue

• difficulty in voiding

• reduction in flow rate

• high-pressure bladder

• slow + prolonged flow

• increase in bladder capacity with reduced contractility (late)

Scrotum

Acutely Symptomatic Scrotum

• = acute unilateral scrotal swelling pain

• Cause:

  • epididymitis:torsion = 3:2 <20 years of age

  • epididymitis:torsion = 9:1 >20 years of age

• TORSION

  • Torsion of testis (20%)

    • = most common acute process in prepubertal age

  • Torsion of testicular appendages accounts for 5% of scrotal pathology; both appendages located near upper pole of testes

    • Frequency:

      • appendix testis:appendix epididymis = 9:1

    • 8 9-mm complex mass in superior aspect of scrotum without color Doppler flow signals

    • mildly enlarged epididymis (75%)

    • blood flow increased in epididymis (60%), scrotal wall (53%), testis (13%) simulating acute epididymoorchitis

• INFECTION / INFLAMMATION (75 80%)

  • Acute epididymitis

    • most common acute process in postpubertal age

  • Orchitis

  • Intrascrotal abscess

  • Sch nlein-Henoch purpura

  • Kawasaki syndrome

  • Insect bite

  • Acute hydrocele

• HEMORRHAGE

  • Testicular trauma

    • Location:  hematoma in scrotal wall, between layers of tunica vaginalis (= hematocele), in epididymis, in testis

    • rapid change in echo character over time

    • disruption of tunica albuginea (= testicular rupture)

  • Hemorrhage into testicular tumor

• HERNIA

  • Scrotal fat necrosis

  • Strangulated hernia

Scrotal Wall Thickening

• Acute idiopathic scrotal edema

  • Incidence: 20 30% of all acute scrotal disorders

  • Age: 5 11 years (range 18 months to 14 years)

  • subcutaneous scrotal edema, erythema

  • minimal pain, afebrile, peripheral eosinophilia

• Epididymoorchitis

• Testicular torsion

• Torsion of testicular / epididymal appendage

• Trauma

• Henoch-Sch nlein purpura

• Cx of ventriculoperitoneal shunt

• Cx of peritoneal dialysis (? leakage of fluid into the anterior abdominal wall + dissection into scrotum)