Carcinosarcoma of the urinary bladder following cyclophosphamide therapy: evidence for monoclonal origin and chromosome 9p allelic loss.

We report a case involving a 45-year-old man with a 12-year history of Wegener granulomatosis, who developed a carcinosarcoma of the urinary bladder after long-term cyclophosphamide therapy. Cyclophosphamide is well recognized as an etiologic agent for urothelial carcinoma of the urinary bladder. However, only 5 cases of carcinosarcoma of the urinary bladder following cyclophosphamide therapy have been reported.