In situ oncocytic change in association with multiple renal cell adenocarcinomas

We report a case of in situ oncocytic change in association with two low-grade renal cell adenocarcinomas and one contralateral low-grade oncocytic adenocarcinoma. The in situ oncocytic change showed abundant cytoplasmic mitochondria confirmed by ultrastructural examination and phosphotungstic acid-hemotoxylin staining. In addition, this in situ oncocytic change expressed cytokeratin CAM 5.2 in the absence of cytokeratin AE1/AE3, as reported in oncocytic renal cell adenocarcinomas. Further study of in situ oncocytic change identified in kidneys resected for adenocarcinomas with regard to follow-up and management of the contralateral kidney seems indicated.