Cyclophosphamide, a cytotoxic alkylating agent, is widely used in various benign diseases like systemic lupus erythematosus (SLE), Wegener's granulomatosis, rheumatoid arthritis, nephrotic syndrome as well as in malignancies and organ transplantation. Cyclophosphamide is metabolized in the liver to various chlormethine metabolites and acrolein, which mediates the toxic effect to the urothelium and can cause hemorrhagic cystitis, bladder fibrosis, and has also been associated with urothelial malignancies including bladder cancer. It is known that SLE is not associated with an increased risk for the development of most of the solid tumors. But it has been suggested that the risk of the bladder cancer increases in patients with benign diseases such as SLE treated by cyclophosphamide. There are only very few reports of cyclophosphamide-induced bladder cancer in SLE so far. We report a case of a patient who developed bladder cancer 13 years after cyclophosphamide was given as therapy for SLE. This case shows that careful observation and urologic evaluation is undoubtedly important for patients treated with cyclophosphamide.

Keywords: Cyclophosphamide, Systemic lupus erythematosus, Bladder cancer