Multilocular cystic renal oncocytoma—Awareness of an unusual morphologic variation

Abstract

Background: Renal oncocytomas are benign epithelial tumors usually detected incidentally. They are typically solid, well-circumscribed, homogenous, mahoganybrown with a central stellate scar. Sometimes, they can have cystic degenerationand rarely present as a multilocular cyst which can be mistaken for other cystic renal carcinomas. Methods: We describe a case of incidentally detected multilocular cystic renal oncocytoma having an unusual gross appearance of multiloculation with perinephric fat invasion. The tumor exhibited tubulocystic architecture posed a diagnostic dilemma. Detailed study of multiple sections coupled with immunohisto chemistry helped elucidate the diagnosis. Till date, only eight cases of multicystic renal oncocytoma have been reported in the English literature. Conclusions: We emphasize the importance of awareness of this unusual morphologic variation to ensure correct diagnosis.