[Kidney oncocytoma: diagnostic and therapeutic approach in the INCMNSZ]

Renal oncocytoma is a benign tumor that in some series represents up to 18% of all solid neoplasms measuring 4 cm or less. Since radiologic distinction between a renal cell carcinoma and oncocitoma is practically impossible, the histologic examination represents the cornerstone of diagnosis. Follow up will be greatly modified by the diagnosis of oncocytoma since it displays a benign course. Eight cases are presented here that were treated at our institution with special mention to diagnosis and therapy.

A retrospective review was performed using records of 288 patients with kidney tumors from 1971 to 2002. Cases had to have several tissue staining including E&O, Schiff's peryodic acid, coloidal Iron, Alcian blue and mucicarmin.

A total of 8 cases (4 men and 4 women) of oncocitoma were detected (2.7%). Patients had a mean age of 50 years (36-69), none had familial history of renal tumors and hipertension was detected in 6. Patients were diagnosed after surgery since radiologic studies suspected renal carcinoma in all patients. The neoplasms measuring more than 8 cm and association with renal cancer in a patient. Follow up was course benign in all patients without recurrence.

Renal oncocytoma represent a small proportion of renal tumors seen in our institution. It must be suspected in solid renal neoplasms measuring less than 4 cm more so if a centrally located scar is seen on CT scan creating a wagon wheel appearance. Definitive diagnosis is made by histologic examination after a chromophobe tumor is ruled out. Since it has a benign course, minimal radiologic follow up is warrented.