[Synchronous multiple carcinosarcoma of the renal pelvis and ureter: a case report].

Carcinosarcoma is a rare biphasic neoplasm, with distinct malignant epithelial and mesenchymal components. A case of carcinosarcoma arising from the upper urinary tract is very rare case. To our knowledge, only 7 cases have ever been reported in Japan. Herein we present a case of carcinosarcoma of the renal pelvis and ureter. A 64-year-old man visited our hospital with gross hematuria. Computed tomography and cystoscopy revealed multiple tumors in the right upper urinary tract and nonpapillary sessile tumor of urinary bladder. Right nephroureterocystectomy and orthotopic ileal neobladder formation were performed. The specimen showed carcinosarcoma in the renal pelvis and ureter, while only urothelial carcinoma component in the urinary bladder by immunohistochemical examination. The patient has remained without any evidence of recurrence for 18 months after operation. Carcinosarcoma has an aggressive malignant potential and poor prognosis. Effective treatment without operation has not been established so far. We recommend a radical operation as soon as possible.