INTRAOCULAR TUMORS

Retinal cavernous hemangioma. This retinal vascular hamartoma is composed of thin-walled, variably sized, interconnecting aneurysms (asterisks) in the inner retina. Variable fibroglial proliferation may occur on the anterior surface of the tumor, causing a whitish color change in the fundus.

Melanocytoma. These intensely pigmented nevi (also called magnocellular nevi) classically involve the optic disc, but can arise from any part of the uvea. In this juxtapapillary choroidal melanocytoma (arrows), the cytologic details are obscured by heavy pigmentation of the nevus cells. Bleached or depigmented sections (inset) are necessary to evaluate the cytologic features of the tumor cells. Note the characteristic plump polyhedral cells with a low nuclear-to-cytoplasmic ratio and bland nuclei.

Ocular melanoma. Transillumination is a key component of the pathologic gross examination of an enucleated eye with melanoma. Transillumination allows for localization of the tumor margins and orientation for gross sectioning. It may also be employed clinically to evaluate anterior tumors.

Ocular melanoma. Ciliochoroidal melanomas may be quite large and exhibit variable pigmentation and focal hemorrhage. The tumor may abut the posterior surface of the lens and induce cataractous changes. A secondary exudative retinal detachment (asterisk) can occur.

Ocular melanoma. Tumor cell type is an important prognostic indicator. A predominantly epithelioid cell tumor carries the greatest risk for metastasis and mortality. Most tumors are mixed cell types (containing both epithelioid and spindle cells). Note the large round cells with round nuclei, prominent nucleoli, abundant cytoplasm, and distinct cell borders (arrows), which are classic epithelioid cells. Intermediate epithelioid cells (arrowheads) are similar but smaller cells with indistinct cell borders.

Choroidal metastasis. The lung is the most common primary site for choroidal metastasis in males. Note the disrupted retinal pigment epithelium, with drusen formation (arrows), elevated Bruch’s membrane, and scattered chronic inflammatory cells within the choroid. Two lobules of metastatic adenocarcinoma of the lung are present within the choroid: one with a papillary configuration (open arrow) and the other with apparent mucin production (arrowhead).

Ocular melanoma. Spindle cells are frequently identified in ciliochoroidal melanoma. Spindle B cells (arrows) are plump cells with spindle-shaped nuclei, prominent nucleoli, and indistinct cell borders. Spindle A cells (open arrows) exhibit thinner spindle-shaped nuclei, with a central chromatin strip or nuclear fold. Note

the spindle B (arrowheads) and spindle A (open arrowheads) cells in cross section.

Choroidal metastasis. The breast is the most common primary site for choroidal metastasis in females. Note the marked thickening of the choroid beneath the relatively intact retinal pigment epithelium and choriocapillaris (arrow) by this metastatic carcinoma of the breast. The tumor exhibits a lobular pattern, with frequent mitotic figures (arrowheads).

Combined hamartoma of the retina and retinal pigment epithelium (RPE). Prominent components of this hamartoma include blood vessels and hyperplastic RPE, which account for the exudation and pigmentation often observed in these lesions. Note the marked thickening of the peripapillary retina, the pigmented epipapillary membrane (arrow), focal cystoid edema (asterisk), numerous blood vessels (arrowheads), and hyperplastic RPE (between brackets). The inset shows hyperplastic RPE (open arrows) surrounding small vascular channels (arrowheads) at higher magnification.

Retinoblastoma. Large tumors may fill much of the vitreous cavity, producing leukokoria. Note the chalky white precipitates (arrowheads) that represent calcium deposition within the tumor. These calcific deposits can be detected by B-scan ultrasonography.

Intraocular/central nervous system lymphoma. This tumor (also called reticulum cell sarcoma) often originates at the level of the retinal pigment epithelium (RPE) internal to (on top of) Bruch’s membrane (arrows). The tumor cells may cause detachment of the RPE or replace the RPE. Note the multilayered infiltrate of viable tumor cells (between brackets) and the retinal necrosis (asterisk) overlying the viable tumor cells. The tumor cells have large and hyperchromatic nuclei and occasional prominent nucleoli. Note the intact choroid, with an infiltrate of chronic inflammatory cells. The inset shows a diagnostic vitreous biopsy specimen with large atypical lymphoid cells (arrows) that have nuclear membrane abnormalities and prominent nucleoli characteristic of ocular lymphoma.

Retinoblastoma. This tumor can originate in any layer of the retina. Note the abrupt transition (arrow) between normal retina and tumor near the ora serrata. Because of its rapid growth, the tumor may outgrow its vascular supply, and extensive areas of necrosis (asterisk) and vitreous seeding (double arrow) are observed in some tumors. In some areas, residual viable tumor cells are present surrounding a blood vessel (inset). This configuration resembles a rosette and is called a pseudorosette (inset). Note the basophilia (dark blue color) in the blood vessel walls (inset) secondary

to deposition of nuclear DNA released by necrotic tumor cells.

Retinoblastoma. Common histologic findings in this tumor are rosettes, including Homer Wright rosettes (arrows), Flexner-Wintersteiner rosettes (arrowheads), and fleurettes (inset) (in order of increasing retinal differentiation). Note the stubby inner segments (open arrow) that characterize the fleurette.

Retinoblastoma. The extent of tumor invasion into the optic nerve on pathologic examination is significant in establishing the prognosis and in dictating further treatment. In this case, the tumor invades the prelaminar optic nerve (anterior aspect of the optic disc), and the prognosis for survival is excellent. The prognosis for survival becomes increasingly poor with posterior extension of the tumor to the lamina cribrosa (between arrows), retrolaminar optic nerve (asterisk), and surgical margin (in order of decreasing survival).