[Oncocytoma of the kidneys].

Fourteen cases (4%) of renal oncocytoma have been detected in a retrospective and current analysis of 350 operative observations of renal carcinoma. Clinical and morphologic (macro-, microscopic, electron microscopic, and angiographic) characteristics of this tumor are described, the differential diagnostic criteria of oncocytoma and renal-cell carcinoma are discussed, as is the prognosis of this condition. The authors point to the possibility of oncocytoma growth into the renal capsule, of invasion into the intra- and extratumor veins, of metastases to the lymph nodes. They recommend distinguishing between well- and intermediately differentiated oncocytomas, for this factor determines the course and prognosis of the disease.