Focal cytomegaly of the adult adrenal cortex. A rare variant of black adenoma.

A pigmented adrenocortical nodule was found incidentally in an adrenal gland resected for endocrine manipulation of breast carcinoma. The sharply circumscribed, nonencapsulated nodule was composed of cells with diameters as large as 95 micron. The cells had ample eosinophilic cytoplasm and contained much lipofuscin pigment. Electron microscopy disclosed tubulovesicular mitochondria, lipofuscin pigment, cytoplasmic vacuolization, and lipid without degenerative changes or intranuclear inclusions. This unusual lesion of adult adrenal glands is best considered as a rare variant of adrenocortical black adenoma.