Fineman_Retina (Color Atlas and Synopsis of Clinical Ophthal

268 6 Retinal and Choroidal Tumors

COMBINED HAMARTOMA OF THE RETINA AND RETINAL PIGMENT EPITHELIUM C ombined hamartoma of the retina and the RPE is a benign, slightly elevated, partially pigmented tumor located around the optic nerve or in the peripheral fundus. It is composed histologically of proliferated glial cells, fibrovascular tissue, and pigment epithe lial cells. Absence of dysplastic cells raises the possibility of an error of development rather than a neoplastic lesion. Epidemiology and Etiology ● The tumor is often diagnosed in the first or second decade. The preponderance of cases in infants and young children suggests that the lesion may be congenital. No familial associa tions are known. ● An association of combined hamartomas, usually macular and sometimes bilateral, has been seen with neurofibromatosis (most commonly type 2). History ● In cases of juxtafoveal lesions, there is painless visual loss from associated epiretinal membrane traction or subretinal exudation. Important Clinical Signs ● Juxtapapillary variant: ill-defined, elevated, charcoal-gray mass adjacent to, or overlying, the optic disc. A gray-white membrane over lying the tumor causes stretching of retinal blood vessels and retinal striae, often involv ing the macula ( Fig. 6-11 ). ● Peripheral variant: slightly elevated, pig mented ridge concentric to the optic disc. There is dragging of dilated retinal vessels toward the lesion by the overlying membrane.

Associated Clinical Signs ● CNV ● Vitreous hemorrhage

● Manifestations of neurofibromatosis type 2 (bilateral acoustic neuromas, brain menin giomas, spinal cord schwannomas, posterior subcapsular cataracts, etc.) Differential Diagnosis ● Choroidal melanoma ● Choroidal nevus ● Reactive hyperplasia of the RPE ● Melanocytoma ● When lightly pigmented and occurring in children, may be mistaken for Rb or toxocariasis ● Epiretinal membrane secondary to infec tious or noninfectious uveitis ● Bergmeister papilla Diagnostic Evaluation ● Diagnosis is based on ophthalmoscopic features. Optical coherence tomography (OCT) demonstrates contour disruption of the macular retinal tissue from the epiretinal membrane. Fluorescein angiography reveals multiple, dilated, fine blood vessels within the tumor, which may become hyperfluorescent as the angiogram progresses ( Fig. 6-12 ). Prognosis and Management ● Because lesions are usually not progressive, regular observation is appropriate. However, contraction of the overlying fibroglial tissue leads to macular distortion, secondary reti noschisis, and retinal holes. ● In cases of visual loss, vitrectomy and mem brane stripping may rarely be performed. Unless there is clear delineation between epiretinal membrane and macular retinal tissue, outcomes from vitrectomy are often unsatisfying.

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