The Wills Eye Hospital Atlas of Clinical Ophthalmology

Editors: Tasman, William; Jaeger, Edward A.

Title: Wills Eye Hospital Atlas of Clinical Ophthalmology , The, 2nd Edition

Copyright 2001 Lippincott Williams & Wilkins

> Table of Contents > Chapter 6 - Tumors of the Uveal Tract

Chapter 6

Tumors of the Uveal Tract

Jerry A. Shields

Carol L. Shields

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Since publication of the first edition of Atlas of Clinical Ophthalmology, there have been several new developments related to intraocular tumors. As with the previous edition, space limitations do not permit a detailed account of all clinical variations, differential diagnoses, diagnostic techniques, pathology, management, and prognosis for all of the tumors that can develop in the iris, ciliary body, choroid, and pigment epithelium (PE). However, a comprehensive, extensively illustrated color atlas of intraocular tumors was recently published which covers details of virtually all intraocular tumors. The reader who wants more detailed information may consult the texts cited in the bibliography. Once again, less common uveal tumors such as leiomyoma, neurilemoma, neurofibroma, and several others are not discussed here. Some comments on tumors of the PE are included, since there have been recent developments regarding their natural course and clinical features.

Iris Tumors

Tumors of the iris can arise from the iris melanocytes, iris smooth muscle cells, and the iris PE. Systemic neoplasms such as lymphoma and metastatic tumors can also affect the iris. Nevus, malignant melanoma, and pigment epithelial tumors will be considered here.

Iris Nevus

Iris nevus is a benign tumor that arises in the melanocytes in the iris stroma. Although most iris nevi remain clinically stationary, they can occasionally give rise to malignant melanoma. Histopathologically, an iris nevus is usually composed of low-grade spindle-type cells. Occasionally, it is composed of deeply pigmented, round cells similar to those seen in the melanocytoma of the optic disc.

Clinical Features

An iris nevus classically appears as a variably-pigmented, well circumscribed lesion in the iris stroma (Fig. 6.1). It may involve any portion of the iris from the pupillary border to the iris root and may be flat or minimally elevated. Occasionally, an iris nevus may occupy an entire sector of the iris from the pupillary border to the anterior chamber angle. In some cases, an iris nevus may be clinically amelanotic (Fig. 6.2). An iris nevus can induce an irregular pupil (Fig. 6.2) or sector cortical cataract.

The differential diagnosis of iris nevus includes iris melanoma, adenoma of the iris PE, iris cyst, foreign body, iris granuloma, and other small circumscribed iris lesions.

Iris nevus is best diagnosed by recognition of the typical lesion with slit lamp biomicroscopy. Ancillary diagnostic studies, such as fluorescein angiography and ultrasonography, have little additional diagnostic value.

Management

An iris nevus is best managed by documentation with accurate drawings or photographs and examination on a yearly basis, looking for evidence of enlargement of the lesion. If growth is detected, malignant transformation into melanoma should be suspected.

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Iris Melanoma

An iris melanoma is a malignant melanocytic tumor that arises from the melanocytes of the iris stroma. Histopathologically, it is composed of spindle cells, epithelioid cells, or a combination of the two (mixed-cell type).

Clinical Features

An iris melanoma is characterized clinically as a variable pigmented, elevated, circumscribed or diffuse, melanocytic neoplasm that affects the iris stroma. It is typically larger than an iris nevus. The lesion most often is deeply pigmented and elevated (Fig. 6.3). In can be amelanotic, or it can be partially pigmented and partially nonpigmented (Fig. 6.4).

An important variant of iris melanoma is the diffuse iris melanoma. It grows as a flat, diffuse, often multifocal mass that covers a large area of the iris surface (Fig. 6.5). The patient with a diffuse iris melanoma typically presents with a clinical syndrome of progressive acquired hyperchromic heterochromia and ipsilateral secondary glaucoma.

Iris melanoma has the capacity to exhibit distant metastasis to the liver and other organs. Lesions that are diffuse and produce secondary glaucoma tend to have a greater tendency to spawn metastatic disease.

The differential diagnosis of iris melanoma is the same as mentioned previously for iris nevus. It is important to differentiate iris melanoma from similar conditions because of the malignant nature of this neoplasm. The diagnosis of iris melanoma is best made by recognition of the typical slit lamp features by an experienced observer. Although fluorescein angiography and ultrasonography have been employed, they add little useful diagnostic information. Fine needle aspiration biopsy can be employed to confirm the diagnosis of diffuse iris tumors when enucleation is being considered.

Management

Once the diagnosis of iris melanoma is clearly established, usually by documentation of progressive growth, the best management is surgical excision of the lesion. Lesions confined to the iris can be managed by removal by partial sector or peripheral iridectomy. Those that extend into the ciliary body require iridocyclectomy or iridogoniocyclectomy. The diffuse iris melanoma is often too large to resect locally and may require enucleation or plaque radiotherapy in selected cases.

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Adenoma of the Iris Pigment Epithelium

An adenoma of the iris PE is a benign neoplasm that arises from the PE of the iris. Histopathologically, it is composed of columns or acini of pigmented epithelial cells.

Clinical Features

Clinically, an adenoma of the iris PE appears as a dark black lesion that can appear in the angle as a rounded mass (Fig. 6.6) or as an irregular, multinodular mass (Fig. 6.7). The lesion typically remains stable or progresses very slowly. Transformation into adenocarcinoma is exceedingly rare.

The differential diagnosis of adenoma of the iris pigment is the same as that for iris nevus and melanoma. The dark black color of the adenoma should suggest the diagnosis.

The diagnosis of adenoma of the iris PE is best made by recognition of its characteristic clinical features.

Management

Small asymptomatic tumors can be managed by simple observation. If the lesion shows progressive enlargement or early secondary glaucoma, removal by iridectomy or iridocyclectomy is warranted.

Melanocytic Tumors of the Posterior Uvea

Choroidal Nevus

A choroidal nevus is a benign melanocytic tumor that arises in the choroid. Although most choroidal nevi remain clinically stationary for many years, they can occasionally give rise to malignant melanoma. Histopathologically, a choroidal nevus is usually composed of low-grade spindle-type cells. Occasionally it is composed of deeply pigmented, round cells similar to those seen in the melanocytoma of the optic disc. Such choroidal melanocytomas are very deeply pigmented.

Clinical Features

Ophthalmoscopically, a choroidal nevus is a variably pigmented, fairly well-circumscribed lesion that usually occurs in the more posterior portions of the choroid. It usually has a gray to black color and is often rather homogeneous (Fig. 6.8). Small drusen may be present on the surface of the lesion (Fig. 6.9). Occasionally, an iris nevus may be clinically amelanotic (Fig. 6.10). Choroidal nevi are usually less than 2 mm in thickness. Accumulation of a small amount of subretinal fluid can occasionally occur. The subretinal fluid may leak into the macular area, causing visual impairment.

The differential diagnosis of choroidal nevus includes small choroidal melanoma, hypertrophy of the retinal pigment epithelium (RPE), hyperplasia of the RPE, combined hamartoma of the retinal epithelium and RPE, subretinal hemorrhage, and other conditions. The amelanotic choroidal nevus must be differentiated from uveal metastasis, granuloma, and choroidal lymphoma. Choroidal nevus is best diagnosed by careful ophthalmoscopy by an experienced clinician who recognizes the typical clinical features. Fluorescein angiography may help to differentiate the lesion from subretinal hemorrhage or from lesions of the RPE.

Management

The best management of a choroidal nevus is periodic ophthalmoscopy, looking closely for enlargement of the lesion. Serial fundus photography is highly desirable in

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Ciliary Body Melanoma

A ciliary body melanoma is a malignant neoplasm that arises from the melanocytes of the ciliary body. Like iris melanoma, it may contain spindle or epithelioid cells.

Clinical Features

Because of the hidden location behind the iris, ciliary body melanoma usually attains a relatively large size before it is detected clinically. However, external ocular signs such as dilated episcleral sentinel vessels (Fig. 6.11) or a focus of transscleral extension of the tumor (Fig. 6.12) can alert the clinician to a possible underlying neoplasm. Frequently, the tumor grows anteriorly through the iris root and appears in the anterior chamber angle (Fig. 6.13). More typically, however, it is confined to the ciliary body and can be detected only by slit lamp or fundus examination after wide dilation of the pupil (Fig. 6.14). Ciliary

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The differential diagnosis of ciliary body melanoma includes iris pigment epithelial cyst and other less common ciliary body tumors such as melanocytoma, leiomyoma, and adenoma of the pigmented or nonpigmented ciliary epithelium. Ciliary body melanoma is best diagnosed by recognition of the typical features of the tumor with slit lamp biomicroscopy or indirect ophthalmoscopy through the widely dilated pupil. If the tumor is of sufficient size, ultrasonography may show the typical features of a uveal melanoma. In cases where the diagnosis is quite difficult, fine needle aspiration biopsy can be used. However, that is a difficult diagnostic technique that requires considerable experience.

Management

Ciliary body melanoma is most often managed by local removal of the tumor by partial lamellar iridocyclectomy or some variation thereof. The technique is described in the literature and is beyond the scope of this discussion. Tumors that are too large to resect locally may require treatment with a radioactive plaque or enucleation.

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Choroidal Melanoma

A choroidal melanoma is a malignant melanocytic tumor that arises from the melanocytes within the choroid. Like ciliary body melanoma, it contains spindle cells, epithelioid cells or a combination of the two (mixed-cell type).

Clinical Features

In its earliest stages, a malignant choroidal melanoma may be clinically indistinguishable from a large benign choroidal nevus. A small choroidal melanoma characteristically occurs as a black or gray choroidal mass with fairly well-defined borders. A typical early feature is the orange pigment on the surface of the tumor (Fig. 6.17). This correlates with clumps of macrophages at the level of the RPE that contain abundant lipofuscin pigment. A larger melanoma usually assumes a dome shape (Fig. 6.18). A melanoma that is clinically amelanotic is characterized by visible large blood vessels in the substance of the tumor. A choroidal melanoma can eventually break through Bruch's membrane, assuming a mushroom-shaped configuration (Figs. 6.19 and 6.20).

The growth patterns of choroidal melanoma can be best appreciated by examining gross sections of eyes enucleated for this disease. The tumors can be dome shaped and deeply pigmented (Fig. 6.21) or amelanotic (Fig. 6.22). The mushroom-shaped tumor typically produces a secondary nonrhegmatogenous retinal detachment (Figs. 6.23 and 6.24).

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The differential diagnosis of choroidal melanoma includes most elevated choroidal or subretinal lesions, such as choroidal nevus, choroidal metastasis, choroidal hemangioma, leiomyoma, neurilemoma, subretinal hemorrhage, the proliferative form of age-related macular degeneration, and tumors of the RPE. The most reliable way to make the diagnosis of choroidal melanoma is with the use of indirect ophthalmoscopy by an experienced observer. In cases that are atypical, ultrasonography, fluorescein angiography, indocyanine green angiography, the radioactive phosphorus uptake (³²P) test and fine needle aspiration biopsy may be helpful ancillary procedures.

Management

The management of choroidal melanoma is controversial. The details of this controversy are discussed in the literature and in the texts cited at the end of this chapter. Enucleation is generally recommended for large tumors with little hope of salvageable vision, and plaque radiotherapy is recommended for melanoma with a hope of salvageable vision. Smaller tumors that are not near the foveal area can be treated with heavy laser application. The treatment of uveal melanoma is variable and each case must be individualized.

Uveal Metastasis

Metastatic cancer to the uveal tract is the most common form of intraocular malignancy. However, many cases with small metastatic foci to the uveal tract have advanced systemic metastasis and few or no visual symptoms and, hence, do not come to medical attention. Therefore, in a clinical practice, uveal metastasis is not as common as primary uveal melanoma.

Most metastatic cancer to the intraocular structures resides in the uveal tract. Metastasis to the retina and optic disc are exceedingly uncommon. Metastatic tumors to the uvea most commonly reach the choroid, with metastasis to the iris and ciliary body being less common. All metastasis to the uvea comes through hematogenous routes, since there are no intraocular lymphatics. The primary malignancies that account for most uveal metastasis are breast cancer in women and lung cancer in men, although a number of other tumors can also spawn uveal metastasis. Since the clinical manifestations of anterior uveal metastasis often differ from those to the choroid, the two will be considered separately.

Anterior Uveal Metastasis

An anterior uveal metastasis is a malignant tumor that has spread from an extraocular primary site by hematogenous routes to the iris and/or ciliary body.

Clinical Features

Clinically, a metastasis to the anterior uvea can have several clinical variations. It can appear as a rather solitary fleshy mass or as a white, fluffy, loosely cohesive mass (Fig. 6.25). These friable tumors can seed tumor cells into the anterior chamber, producing a tumor-induced pseudohypopyon (Fig. 6.26). In other cases, an iris metastasis can bleed, causing a spontaneous hyphema (Fig. 6.27). Because of the friable nature of many anterior uveal metastases,

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The differential diagnosis of anterior uveal metastasis includes amelanotic uveal melanoma, granulomatous iridocyclitis, opportunistic infection, lymphoma, and other nonpigmented iris lesions.

The most important diagnostic step is recognizing the typical clinical features with slit lamp biomicroscopy. Since most patients with iridociliary metastasis have a history of systemic cancer, it is important to take a history to elicit previously treated neoplasm. In the occasional case where the iris metastasis is the first sign of a systemic malignancy, a fine needle aspiration biopsy can be performed to make the diagnosis and possibly to identify the primary site of the neoplasm.

Management

The management of an anterior uveal metastasis involves initiating a systemic evaluation to identify other sites of systemic metastasis. If chemotherapy is to be employed for the systemic disease, the anterior uveal metastasis can be cautiously observed for signs of regression. If systemic chemotherapy does not control the uveal metastasis, ocular irradiation, giving approximately 3500 cGy over a 4- to 5-week period, is advisable.

Choroidal Metastasis

A choroidal metastasis is a malignant neoplasm that spreads to the choroid from a distant primary cancer.

Clinical Features

Clinically, a choroidal metastasis is usually different from a metastasis to the iris or ciliary body. It is confined by Bruch's membrane and does not exhibit the seeding that often characterizes anterior uveal metastasis. Hence, the choroidal metastasis is usually more circumscribed. It appears as a cream-yellow sessile or minimally elevated mass (Fig. 6.28). Unlike an amelanotic choroidal melanoma, it is often multifocal (Fig. 6.29) and bilateral. Choroidal metastasis located near the optic disc has a propensity to infiltrate the nerve and produce disc edema and superficial hemorrhage (Fig. 6.30).

The differential diagnosis of choroidal metastasis includes amelanotic choroidal melanoma, choroidal hemangioma, lymphoma, posterior scleritis, and granulomatous

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Management

The management of choroidal metastasis is similar to that described above for anterior uveal metastasis. If the patient is receiving chemotherapy for systemic disease, the choroidal metastasis can be followed without direct ocular treatment. If there is no systemic indication for chemotherapy, or if chemotherapy fails to control the choroidal metastasis, ocular radiotherapy should be employed. About half of the patients with choroidal metastasis require ocular irradiation and half can be successfully controlled with chemotherapy or hormone therapy.

Choroidal Hemangioma

Choroidal hemangioma is the most important vascular tumor of the uveal tract. It can occur as a circumscribed lesion that is unassociated with any extraocular manifestations or as a diffuse type that is usually associated with facial nevus flammeus or variations of the Sturge-Weber syndrome. Unlike uveal melanoma, uveal hemangioma occurs only in the choroid.

Circumscribed Choroidal Hemangioma

A circumscribed choroidal hemangioma is a localized benign vascular tumor that occurs in the posterior uveal tract.

Clinical Features

Circumscribed choroidal hemangioma usually appears as a sessile or minimally elevated, red-orange mass that has a similar color to the surrounding normal fundus. Smaller lesions (Fig. 6.31) are rather homogenous and do not usually produce a secondary retinal detachment. Larger lesions (Fig. 6.32) may produce overlying proliferation or metaplasia of the RPE and secondary retinal detachment.

The differential diagnosis of choroidal hemangioma is the same as for choroidal melanoma and choroidal metastasis. The diagnosis of circumscribed choroidal hemangioma is best made by recognition of the typical red-orange color of the choroidal mass. Such a color is not usually seen with amelanotic choroidal melanoma, choroidal metastasis, or other choroidal masses.

Management

Since circumscribed choroidal hemangioma is a benign lesion that usually remains stationary or demonstrates only minimal enlargement, asymptomatic tumors generally require no treatment. If the tumor produces a secondary retinal detachment that causes visual impairment, laser photocoagulation to control the detachment is often warranted.

Diffuse Choroidal Hemangioma

The diffuse choroidal hemangioma occurs ipsilateral to a facial nevus flammeus, sometimes in association with the Sturge-Weber syndrome.

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Clinical Features

Clinically, a diffuse choroidal hemangioma appears as a broad, red-orange thickening of the posterior choroid. The tumor appears redder than the background fundus, a finding sometimes called the tomato catsup fundus (Fig. 6.33). With time, the choroidal hemangioma produces cystic retinal degeneration and eventually an extensive secondary retinal detachment (Fig. 6.34).

The differential diagnosis of diffuse choroidal hemangioma includes other causes of choroidal thickening and secondary retinal detachment. Hence, it can be similar to a diffuse choroidal melanoma, choroidal metastasis, and possible posterior scleritis. The presence of an ipsilateral facial nevus flammeus in a patient with a nonrhegmatogenous retinal detachment should suggest the diagnosis. If there is any question regarding diagnosis, ultrasonography and fluorescein angiography can provide diagnostic assistance. Cranial computed tomography or magnetic resonance imaging to detect the meningeal calcification of the Sturge-Weber syndrome may also provide diagnostic help.

Management

The choroidal hemangioma of the Sturge-Weber syndrome can be difficult to manage. In its earliest stages, a refraction and treatment for hyperopic amblyopia is the best approach. Later, the secondary retinal detachment is best managed by laser photocoagulation or retinal detachment surgery, depending on the extent of the disease.

Choroidal Osteoma

Choroidal osteoma is a recently recognized osseous tumor of the choroid that has distinct clinical and histopathologic features. It is a benign choroidal tumor composed of mature bone that occupies a full-thickness area of the posterior choroid.

Clinical Features

Clinically, choroidal osteoma characteristically occurs as a well-delineated, sessile yellow-orange tumor in the posterior choroid, usually in a juxtapapillary (Fig. 6.35) or circumpapillary location (Fig. 6.36). Occasionally, a choroidal osteoma is located in the macular area and does not touch the optic disc (Fig. 6.37). The well-defined

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Management

There is no known treatment for a choroidal osteoma. When the tumor induces subretinal neovascularization or choroidal origin, laser treatment to the neovascular membrane may be warranted.

Lymphoid Tumors

Benign and malignant tumors of lymphoid origin can also affect the uveal tract. A uveal lymphoid lesion can occur with only ocular involvement, or it can be a part of a systemic lymphoma. It may be impossible clinically to distinguish a benign lymphoma (reactive lymphoid hyperplasia) from a malignant lymphoma on the basis of ocular examination. Lymphoma can occur as a retinovitreal infiltrate that can simulate intraocular inflammation, or it can occur as a uveal infiltration. Only the uveal variant will be considered here. A lymphoid tumor of the uvea is an infiltration of the uveal tract by benign or malignant tumor composed of a proliferation of abnormal lymphocytes.

Clinical Features

A lymphoid tumor of the iris appears as an amelanotic diffuse or circumscribed mass in the iris (Fig. 6.39). In the choroid, it appears as one or more yellow choroidal lesions that are indistinguishable from a choroidal metastasis (Fig. 6.40).

The differential diagnosis of uveal lymphoid tumor is the same as for uveal metastasis and amelanotic uveal melanoma. The diagnosis of a uveal lymphoma is best made by recognition of the uveal lesion with slit lamp biomicroscopy or indirect ophthalmoscopy. A general evaluation to detect a systemic lymphoma can be very helpful in establishing the diagnosis.

Management

The management of uveal lymphoma is the same as for uveal metastasis. Systemic chemotherapy should be employed for systemic disease, with the addition of ocular radiotherapy if tumor control is not achieved.

Leukemia

Leukemia most often affects the ocular fundus by causing retinal hemorrhages secondary to the hematological alterations associated with the disease. However, direct infiltration of the uveal tract and the retina by leukemic cells occasionally occurs. Intraocular involvement by leukemia consists of infiltration of the uveal tract and retina by malignant leukocytes as part of the systemic disease.

Clinical Features

Leukemic infiltration of the iris usually appears as a diffuse friable mass in the inferior iris, often associated with a hyphema (Fig. 6.41). Early leukemic involvement

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Most patients with intraocular involvement by leukemia have a long-term history of leukemia. The positive history and the clinical findings should suggest the diagnosis. In cases where differentiating between leukemic infiltration and opportunistic infection or other neoplasm is difficult, we have most commonly employed fine needle aspiration biopsy to help make the diagnosis.

Management

The management of leukemic infiltration of the intraocular structures is similar to the management of uveal metastasis. If chemotherapy that is employed for the systemic disease does not control the ocular disease, ocular irradiation should be initiated. In cases of infiltration of the optic nerve, irradiation should be promptly considered because of the poor visual prognosis.

Tumors of the Nonpigmented Ciliary Epithelium

Tumors that arise from the nonpigmented epithelium of the ciliary body can be divided into congenital and acquired types. The most important congenital tumor is the medulloepithelioma.

Medulloepithelioma

Intraocular medulloepithelioma most often occurs unilaterally in young children in the first decade of life. Intraocular medulloepithelioma is an embryonic neoplasm arising from the primitive medullary epithelium that is destined to form the nonpigmented ciliary epithelium in the adult. Cytologically, it can be benign or malignant, but it rarely exhibits distant metastasis. Both the benign and malignant variants can occur as a nonteratoid type or a teratoid type. The nonteratoid type consists of a proliferation of fairly well-differentiated cells of the nonpigmented ciliary epithelium. The teratoid type contains heterologous elements such as cartilage and skeletal muscle.

Clinical Features

In the early stages, medulloepithelioma appears as a gray-white tumor of the ciliary body (Fig. 6.44). As it slowly enlarges, it can cause a subluxation of the lens, secondary cataract, secondary glaucoma, retinal detachment, and a white pupillary reflex (leukokoria) (Fig. 6.45). A characteristic feature is the development of clear cysts that are visible near the surface of the lesion. These cysts frequently break away from the main lesion and float freely in the vitreous or aqueous cavity. The main lesion continues to slowly enlarge and can eventually fill the entire globe and, rarely, extend through the sclera into the orbit.

The differential diagnosis of intraocular medulloepithelioma includes retinoblastoma, persistent hyperplastic vitreous, ocular trauma, and other childhood conditions. The best method of diagnosis of medulloepithelioma is recognition of the clinical features described above, using slit lamp biomicroscopy and indirect ophthalmoscopy. If the diagnosis

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Management

The management of intraocular medulloepithelioma is removal of the tumor by partial lamellar sclerouvectomy when the tumor involves less than 4 clock hours of the pars plicata. Although that procedure is often successful, there is a tendency for recurrence. Hence, many cases ultimately require enucleation. The systemic prognosis is generally quite favorable.

Acquired Adenoma and Adenocarcinoma

Acquired neoplasms can develop from the fully formed nonpigmented ciliary epithelium. Unlike the embryonic medulloepithelioma of childhood, these tumors do not contain teratoid elements. From a cytologic standpoint, they can be benign (adenoma) or malignant (adenocarcinoma). Even the malignant variant has little or no tendency to exhibit metastatic disease. An acquired adenoma or adenocarcinoma of the nonpigmented ciliary epithelium is a neoplasm that develops from fully mature adult nonpigmented ciliary epithelium.

Clinical Features

Like the embryonic variant, the acquired tumor of the nonpigmented ciliary epithelium begins as an amelanotic mass of the pars plicata. It can have a smooth or irregular surface, and it occasionally contains clear cysts. It can produce a secondary cataract (Fig. 6.46). The differential diagnosis includes amelanotic melanoma of the ciliary body, metastatic carcinoma, leiomyoma, granuloma, and possibly other lesions. The experienced ocular oncologist can often make the diagnosis of this uncommon entity by slit lamp examination and indirect ophthalmoscopy. Fluorescein angiography and ultrasonography do not provide much diagnostic help in differentiating this lesion from the aforementioned conditions. Fine needle aspiration biopsy can be employed in difficult cases.

Management

The management of acquired tumor of the nonpigmented ciliary epithelium is removal of the mass by partial lamellar sclerouvectomy. Although this surgery is quite difficult, in many cases the tumor can be successfully removed (Fig. 6.47). Enucleation is necessary for larger or recurrent tumors.

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Acquired Tumors of the Ciliary and Retinal Pigment Epithelium

True tumors can develop in the PE of the ciliary body and retina. Both benign adenoma and malignant adenocarcinoma are locally aggressive tumors that lack potential to metastasize, but they can cause complications leading to visual loss. Since adenoma and adenocarcinoma are similar clinically and in their biologic behavior, they are discussed together.

Clinical Features

A neoplasm of the PE is usually, but not always, dark brown or black in color. When it develops in the ciliary body region, it can grow slowly and produce subluxation of the lens and invasion of the anterior chamber. When it arises in the retina, it appears as a relatively stable, abruptly elevated mass. It is known to occasionally develop in an eye that has experienced trauma or inflammation. It can also arise from an area of congenital hypertrophy of the RPE and from a small focus of hyperplasia of the PE. It is now recognized that a neoplasm of the PE can develop a feeding retinal artery and a draining retinal vein and can induce retinal exudation, exudative retinal detachment, and orbital extension.

The most important condition in the differential diagnosis is uveal melanoma. The typical features described may assist in suspecting the diagnosis. Fluorescein angiography and ultrasonography can also help in determining the diagnosis.

Management

If the diagnosis of acquired tumor of the PE is suspected and the lesion is asymptomatic, a period of observation is justified. Larger, more aggressive tumors can be managed by local resection if they are located in the ciliary body region. More posterior lesions may require irradiation of even enucleation.

Bibliography

Shields JA, Shields CL. Intraocular tumors. A text and atlas. Philadelphia: WB Saunders; 1992.

Shields JA, Shields CL. Atlas of intraocular tumors. Philadelphia: Lippincott Williams & Wilkins; 1999.

(The above references are comprehensive and cite hundreds of additional references on the subject of intraocular tumors.)