[Sarcomatoid carcinoma of the kidney associated with urothelial carcinoma: report of a case with unusual clinical presentation].

We report a case of sarcomatoid renal cell carcinoma and simultaneous transitional cell carcinoma of the renal pelvis in a 77 year old man admitted for uroseptic fever persisting for two months. Seven years earlier he underwent cystectomy with ureterosigmoidostomy for transitional cell carcinoma of the bladder. CT scan described a severe hydronephrosis with dilated pelvis, several pseudocystic formations with renal parenchima thinning and absence of contrast excretion. Radical nephrectomy was performed consequent to a clinical diagnosis of uroseptic fever in secondary hydronephrosis due to stenosis of ureterosigmoidostomy. Tumors were suspected on cut section and confirmed by histological examination.