Primary carcinosarcoma: a rare cause of unilateral ureteral obstruction.

We report a case of unilateral ureteral obstruction owing to carcinosarcoma of the distal ureter. Tumor recurred 6 months after ureteronephrectomy and the patient died 2 1/2 years later. A review of the literature revealed only 3 other cases of ureteral carcinosarcoma, all of which had a similar aggressive course. Recognition and separation of this entity from the more usual transitional cell carcinoma are important because of its apparent poorer prognosis.