[Rhabdomyosarcoma of the kidney in children].

Two cases of renal rhabdomyoid sarcoma with alveolar structures are described. Both children were under one year of age. In one of them the tumour was found at the age of two weeks and was combined with congenital anomaly of the calyx-pelvis system. The tumors were detected incidentally in both children who entered the hospital with the diagnosis of Wilms' tumour. Excretory urography revealed in one case the picture which somewhat differed from that typical for nephroblastoma. The histological and electron-microscopic examinations were performed in both cases. Differential diagnosis from rhabdomyosarcoma is discussed.