[Transitional cell carcinoma of pelvis in a giant hydronephrotic kidney].

A 73-year-old man complained of macroscopic hematuria. Preoperative diagnosis was left giant hydronephrosis due to UPJ stenosis. Resected kidney unsuspectedly contained multiple papillary tumors. Ureterectomy and partial cystectomy was additionally performed. Histological examination showed transitional cell carcinoma. Urinary stasis in the dilated pelvis may have been one of the causes of carcinomatous changes in the epithelium in our case.