Renal oncocytoma. A phenotypic and genotypic entity of renal parenchymal tumors.

The light and electron microscopic morphology of two renal parenchymal tumors was consistent with the diagnosis of renal oncocytoma. Both tumors had a mosaic chromosome pattern of cells with normal and abnormal karyotypes. No recurrent chromosome aberration and also no rearrangement of chromosome 3p was found. Restriction analysis of the mitochondrial DNA revealed a new autoradiographic band at about 50 basepairs in size occurring exclusively in oncocytomas. The possible use of these findings in the diagnosis of renal oncocytomas is discussed.