Renal oncocytoma. Report of five cases and review of literature.

Cases of renal cell carcinomas seen between 1963 and 1977 were reviewed. Five of these cases (4.66%) were reclassified as renal oncocytomas. The distinctive appearance of this lesion is a well circumscribed, uniform tan-brown tumor with a prominent central scar and lack of necrosis or hemorrhage. Light and electron microscopy confirmed the oncocytic features of the tumor cells. A possible association with smoking is suggested. Angiographic studies may assist in preoperative diagnosis. The clinical course of patients with renal oncocytoma is definitely benign.