Fineman_Retina (Color Atlas and Synopsis of Clinical Ophthal

258 6 Retinal and Choroidal Tumors

RETINAL CAPILLARY HEMANGIOBLASTOMA O riginally termed angiomatosis retinae , retinal capillary hemangioblastoma is a benign vascular tumor of variable size located in the retina or adjacent to the optic disc. Usu ally diagnosed by the fourth decade, it may be the first manifestation of von Hippel–Lindau (VHL) disease, a familial cancer syndrome with which it is commonly associated. Epidemiology and Etiology ● This tumor may occur in a sporadic or hereditary manner. Retinal capillary heman gioblastoma occurs in up to 80% of patients with VHL syndrome and is often the first man ifestation, diagnosed at a mean age of 25 years. ● The VHL syndrome has an estimated prev alence of 1 in 40,000 and is possibly more common in Whites. It exhibits dominant in heritance and has variable phenotypes within families. ● Mean survival of patients with VHL is 41 years of age. ● VHL syndrome is caused by mutations in the VHL gene, a tumor suppressor gene located on chromosome 3p25. The VHL gene product regulates the expression and function of hypoxia- responsive angiogenic factors (e.g., VEGF). History ● Capillary hemangioblastomas may be di agnosed incidentally or in patients suspected of having VHL syndrome. The tumors may be asymptomatic or may produce painless visual impairment from vitreous hemorrhage, macular pucker, or retinal detachment. Severe vision loss may occur when the tumor occurs on the optic nerve head. Important Clinical Signs ● Retinal capillary hemangioblastoma: usually located peripherally and well

circumscribed. It initially appears as a yellow-red dot with a minimally dilated “feed ing” arteriole or draining venule ( Fig. 6-5 ). With growth, it appears orange-red with more prominently dilated afferent and efferent ves sels. It may have associated exudation, subret inal fluid, or preretinal fibrosis. ● Juxtapapillary capillary hemangioblastoma: orange-red in color, but less well circum scribed. It often lacks feeder vessels. ● VHL syndrome: hemangioblastomas of the cerebellum and spinal cord, renal cell carci noma, or pheochromocytoma Associated Clinical Signs ● Retinal detachment and, rarely, neovas cular glaucoma may complicate capillary hemangioblastoma. ● Hemangioblastomas of the adrenal glands, lungs, and liver, and multiple cysts of the pancreas and kidneys have been observed in some patients with VHL syndrome. Differential Diagnosis ● Retinal capillary hemangioblastoma ■ Other tumors: retinal cavernous heman gioma, racemose hemangioma, choroidal melanoma, and astrocytic hamartoma ■ Vascular diseases: Coats disease, retinal arterial macroaneurysm, familial exudative vitreoretinopathy, and exudative macular degeneration ■ N.B. : A distinction has been made between the retinal angioma of VHL syn drome and an acquired, nonhereditary en tity occurring in older patients and termed vasoproliferative retinal tumor . This latter condition is usually located in the infero temporal peripheral fundus, lacks markedly dilated feeder vessels, and is often associ ated with intraocular inflammation. ● Optic disc hemangioma ■ Papillitis

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