Heterotopic adrenocortical oncocytoma. A case report with light and electron microscopic studies.

BACKGROUND: The case of a benign oncocytoma arising in a patient from retroperitoneal heterotopic adrenocortical tissue is reported; this tumor was found in a 44-year-old man. METHODS: The tumor consisted of polygonal cells with granular eosinophilic cytoplasm packed with swollen mitochondria. RESULTS: Scattered tumor cells showed abundant smooth endoplasmic reticulum suggesting that the tumor was of adrenocortical origin.