Renal oncocytoma.

Several authors have recently drawn attention to renal oncocytoma, a neoplasm hitherto rarely recognized. Their reports suggest that renal oncocytomas are not uncommon and that they are benign and possess distinctive gross, microscopical, ultrastructural, and behavioral features. Most examples were discovered on re-examination of neoplasms previously classified as renal adenocarcinoma or adenoma. In a survey of renal neoplasms filed in our Department, we identified 8 cases; these are reported and the literature is reviewed.