Bilateral renal oncocytomas: management and nuclear analysis

Only 16 cases of bilateral renal oncocytomas have been previously reported in the English language literature, 9 of which were treated with bilateral surgical resections. We report a case treated with bilateral partial nephrectomy. Although pathological examination revealed grade I oncocytomas on both sides, flow cytometry demonstrated tumor DNA content to be aneuploid on one side and diploid on the other, the first cellular differences reported in a case of bilateral renal oncocytomas. The management of suspected renal oncocytomas is discussed, with emphasis on the need for complete excision in most patients. The results of nuclear studies of these tumors, including DNA flow cytometry, cytogenetics, and molecular analysis of both nuclear and mitochondrial DNA, are reviewed.