[Three cases of proliferative cystitis causing hydronephrosis].

We report three cases of proliferative cystitis causing hydronephrosis. Three patients presented with a complaint of miction pain, gross hematuria or pollikisuria. Cystoscopic findings revealed papillary sessile tumor from neck to orifice. Transurethral resection of the bladder tumor (TURBT) was performed because the tumor was not responsive to medical treatment. The pathological diagnosis was intestinal type or typical type of cystitis glandularis and no malignant cells were observed. After the operation, although hydronephrosis improved in two cases, the left hydronephrosis did not improve in one case and ureteralileostomy was performed. Five year after the last operation, there is no evidence of recurrence of the tumor. Tumor formation arising from proliferative cystitis is relatively rare. Pathogenesis and management of this rare condition are discussed.