Squamous cell carcinoma of the bladder associated with cyclophosphamide therapy for Wegener's granulomatosis: a report of 2 cases.

Cyclophosphamide has been used to treat a variety of malignant and nonmalignant diseases. The association of this agent with the development of urothelial tumors has been well documented. Although most bladder cancers associated with prior cyclophosphamide therapy are transitional cell carcinoma, to our knowledge there have been 6 reports of cyclophosphamide-induced squamous cell carcinoma of the bladder. We report 2 additional cases of squamous cell carcinoma of the bladder that occurred in patients after cyclophosphamide treatment for Wegener's granulomatosis. Any patient with a history of prolonged cyclophosphamide ingestion needs careful long-term monitoring of the lower urinary tract, since there is at least a 9-fold increase in the incidence of lower urinary tract malignancy in such patients.