Renal oncocytoma
Renal oncocytoma is a distinct, pathologically defined neoplasm composed entirely of oncocytic cells. Current controversy includes differentiating a true benign oncocytoma from a granular eosinophilic renal cell carcinoma (RCC). Previously described 'grade II' oncocytoma and metastatic oncocytomas may actually represent these RCC variants and not true oncocytoma. Although classic radiographic appearance of oncocytoma shows a central scar and spoke-wheel vascular pattern, there are no pathoneumonic radiologic features, and distinguishing between this entity and some RCCs is impossible with these tests. The diagnosis of oncocytoma remains pathologic; sampling of the entire lesion is necessary. If the diagnosis of oncocytoma can be assured at the time of surgical exploration, then renal-sparing operations are indicated.
