Fineman_Retina (Color Atlas and Synopsis of Clinical Ophthal

264 6 Retinal and Choroidal Tumors

CONGENITAL HYPERTROPHY OF THE RETINAL PIGMENT EPITHELIUM C ongenital hypertrophy of the retinal pig ment epithelium (CHRPE) is a benign, asymptomatic condition, consisting of one or more well-demarcated, pigmented, flat, non progressive lesions, usually found in the equa torial or peripheral fundus. In rare instances, multifocal lesions may be associated with famil ial colonic polyposis (Gardner syndrome). Epidemiology and Etiology ● The condition is likely congenital. ● It occurs with equal frequency among vary ing genders and ethnicities. History ● Patients are usually asymptomatic. Often, the disorder is noted as an incidental finding during ophthalmoscopy. Important Clinical Signs ● Two forms have been described: Solitary: unilateral, deeply pigmented, flat, circular lesion measuring 1 to 6 mm in diameter. Usually sharply demarcated, the lesion may be solid black ( Fig. 6-8A ) or ringed with a small border of hypopigmen tation. Lacunar areas of depigmentation within the lesion may be seen ( Fig. 6-8B ). Multifocal: also termed congenital grouped pigmentation or “bear tracks.” Groups of 3 to 30 small (0.1 to 2 mm) lesions typically appear in one sector of the midperipheral retina. Usually, they lack the internal lacu nae and hypopigmented halo of the solitary form ( Fig. 6-9 ). ● Multifocal fundus lesions resembling CHRPE have been reported in close associ ation with familial adenomatous polyposis

(Gardner syndrome and Lynch syndrome; Fig. 6-10 ), heritable conditions of colonic polyps, and extraintestinal osteomas and fibromas with invariable progression to colonic cancer. The lesions associated with Gardner syndrome, however, are typically bilateral, have irregular borders, and are often scattered in the fundus. ● Testing for the causative genes ( APC and MUTYH ) is available. Differential Diagnosis ● Malignant choroidal melanoma ● Choroidal nevus ● Combined hamartoma of the retina and the retinal pigment epithelium (RPE) Diagnostic Evaluation ● Diagnosis is based on typical ophthalmo scopic features. By fluorescein angiography, the tumor exhibits persistent hypofluores cence. Lacunar areas are seen as hyperfluo rescent, consistent with depigmentation of the RPE. Prognosis and Management ● Most CHRPE lesions are typically non progressive and require only periodic examination. ● In rare instances, adenocarcinomas may emerge from within the CHRPE ( Fig. 6-8C ). Untreated nodular lesions have been shown to progress into pedunculated tumors and may lead to serous retinal detachment in rare cases. Adenocarcinomas of the RPE rarely demonstrate extraocular extension and are rarely associated with metastases. ● Patients with bilateral lesions suggestive of those seen in Gardner syndrome should be referred for colonoscopy and potential genetic testing. Because the gene is inherited in an autosomal dominant manner, genetic testing of family members should be considered.

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