Renal oncocytoma. Review of our 22 patients

Renal oncocytoma (OR) is a benign tumor. It may represent up to 3-7% of solid kidney masses, and shows specifics cellular and evolutive characteristics. Metacronicity, multifocality and bilateralism has been reported. Between 1986 and 2005, 478 kidney tumors have been surgically treated at our institution. We report the frequency and characteristics of OR in our patients, compared with renal cell carcinomas (RCC). We try to find out the rate of multifocality, bilateralism and other tumor association, and the number of neoplasms originally diagnosed as OR before surgery. Mean and median follow up: 36.86 and 13 months (1-193). Specific survival rate 100%. We found 24 OR in 10 men and 12 women with a mean age of 59 years (34-84). 12 in the left kidney and 12 in the right one, one patient presenting oncocytomatosis. Tumor mean size was 4.64 cm (1-12.5 cm). Tumors were discovered incidentally in 17 cases. Presentation symptoms in the rest of patients were gross hematuria. The rate of OR found in our sample population of renal tumors undergoing surgery matches other series already published. Two synchronic OR, but not metacronous, bilateral or metastatic tumors were found. All cases presented a benign evolution.