Fineman_Retina (Color Atlas and Synopsis of Clinical Ophthal

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Retinal and Choroidal Tumors 6 ■ David A. Reichstein and Franco M. Recchia

ASTROCYTIC HAMARTOMA A strocytic hamartoma is a congenital, min- imally progressive, benign tumor arising from the glial cells of the retina and usually lo cated around the optic disc. It is often associated with the systemic condition tuberous sclerosis (TS; Bourneville disease), occasionally with neu rofibromatosis or retinitis pigmentosa but also oc curs sporadically in otherwise normal individuals. Epidemiology and Etiology ● Most astrocytic hamartomas occur con genitally in association with TS, a familial phakomatosis characterized by the triad of seizures, mental retardation, and skin lesions. TS has an estimated incidence of 1 in 15,000 to 1 in 100,000 and exhibits autosomal dominant inheritance. Roughly half of the patients with TS have astrocytic hamartomas. Causative genes ( TSC1 and TSC2 ) have been identified on chromosomes 9q34 and 16p13. History ● Patients with astrocytic hamartomas are usually asymptomatic. Visual field testing, if clinically feasible, may reveal a scotoma in the area corresponding to the tumor.

Important Clinical Signs ● The appearance of a retinal astrocytic ham artoma is principally of two types: Smaller, noncalcified, flat, smooth tumor that appears as mild thickening of the nerve fiber layer Larger, calcified, whitish-yellow nodular mass (mulberry lesion) ● Aspects of both may be seen in the same lesion, as it is likely that calcification pro gresses slowly over many years ( Fig. 6-1 ). ● Punched-out depigmented retinal pigment epithelial lesions can be an ocular manifesta tion of TS complex. ● Every patient with an astrocytic hamartoma of the retina or optic nerve must be evaluated for TS. Typical manifestations of TS are as follows: Skin lesions (~95% incidence) Hypomelanotic macules: oval (ash-leaf), polygonal, or punctate (confetti) in shape. Usually present at birth and often the first presenting sign Reddish-brown papular rash over the face (termed adenoma sebaceum , but actually angiofibromas), often mistaken for acne. Rarely present before a few years of age.

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