Bilateral multifocal renal oncocytoma: case report and review of the literature.

We report an unusual case of bilateral multifocal renal oncocytoma. The patient underwent bilateral enucleation of 4 tumors of the right and 4 tumors of the left kidney. Frozen section and permanent pathological diagnosis was renal oncocytoma for all tumors. Only 5 other cases of bilateral multifocal oncocytoma have been reported in the literature, of which only 2 had pathological confirmation of the diagnosis. It is important to recognize the potential for multicentric bilateral oncocytomas and to attempt a renal sparing approach in these cases. However, we performed enucleation of all large lesions due to the documented coexistence of renal oncocytoma and renal cell carcinoma as separate simultaneous lesions.