[Rare kidney tumors]

During the period from 1976 to 1986, a total of 518 kidney tumor patients were treated in the Department of Urology at the University of Freiburg, West Germany. In 34 cases (6.6%) the examination revealed a tumor that was neither a renal cell carcinoma nor a renal pelvic urothelial carcinoma (i.e., a rare renal tumor). Through diagnostic imaging procedures the presence of a tumor was correctly diagnosed in 97% of these 34 cases. Conservative treatment methods were used with 5 patients (4 with renal angiomyolipoma and 1 with hemangioma) whose conditions were clearly diagnosed. In these patients operative therapy was not indicated. The precise histological diagnosis found in 29 patients subjected to surgery was the same as the preoperative diagnosis in only 8 cases (27.6%). Histologically, 20 benign (4 epithelial, 16 mesenchymal) and 9 malignant (3 epithelial, 3 mesenchymal, 3 mixed) tumors were found. The operative methods for rare kidney tumors are the same as those used for the more common kidney tumors. Only in the presence of tumors that are clearly benign, such as angioma or angiomyolipoma, is a wait and see policy with frequent examinations recommended.