Melanosis of the choroid plexua.

A unique case of melanosis of the choroid plexus in a 74-year-old man who died of hypertensive cardiovascular disease is described. The cerebral lesion did not cause symptoms. The proposed pathogenesis is the conversion of choroidal epithelial lipofuscin into melanin. Our findings also may explain the origin of a previously reported primary malignant melanoma of the choroid plexus and of black cortical adenomas of the adrenal gland.