Determining the diagnosis of an oncocytic renal neoplasm: a case report

This is the case of a 45 year old male patient with an oncocytic renal neoplasm that was difficult to classify. Histology from a partial nephrectomy revealed a tumour comprising oncocytic cells containing rounded nuclei with some prominent nucleoli, although no necrosis or lymphovascular invasion. CK7 immunohistochemistry was focally positive, with only weak staining for CD117. There are multiple lesions to consider in the differential diagnosis of oncocytic renal tumours with borderline features between oncocytoma and chromophobe carcinoma. The increasing use of molecular pathology is also important in the diagnosis of some entities.