Adenocarcinoma arising from congenital hypertrophy of retinal pigment epithelium.

Congenital hypertrophy of the retinal pigment epithelium (CHRPE), traditionally regarded as a benign stationary condition, has recently been shown in 5 cases to give rise to an elevated, solid tumor. However, the histopathologic nature of the tumor that arises from CHRPE has not been previously determined. A 65-year-old woman developed a progressively enlarging peripheral fundus tumor that arose from a focus of classic CHRPE. The tumor produced a localized exudative retinal detachment, cystoid macular edema, and surface-wrinkling retinopathy. The mass was removed by local resection, and histopathologic examination revealed a low-grade adenocarcinoma of the retinal pigment epithelium, apparently arising from CHRPE. Although CHRPE is usually a benign nonprogressive lesion, it can give rise to a malignant tumor. Congenital hypertrophy of the retinal pigment epithelium should be observed periodically for development of a neoplasm.