1983 Volume 74 Issue 3 Pages 436-445
A renal oncocytoma is a rare tumor which is composed of oncocytes, with a large acidophilic cytoplasm containing abundant mitochondria. Renal oncocytes are believed to originate from proximal tubular cells. This case report will become the third case ever reported in Japanses literature. A 41 year-old man was referred because of hypertension and proteinuria. Radiological examinations revealed a tumor in the right kidney and nephrectomy was subsequently performed. The resected tumor measured 8.5×5.0cm was well-circumscribed and uniformly tan-brown in color without any necrosis or hemorrhage. Light and electron microscopy confirmed the diagnosis of renal oncocytoma. Light and dark stained cells were observed, and their presence was confirmed by an epoxy resin section stained with toluidine blue. The electronmicroscopic characteristics of the light cells were compatible with those of “classical” oncocytes. As the dark cells had pyknotic nuclei and also more abundant mitochondria, they were considered to be a kind of degenerative cell which had most likely originated from the light cells.
Clinical findings on renal oncocytomas based on the 61 cases reported in available literature are also reviewed and discussed in detail.
