Frequent recurrence of superficial bladder tumors in the periorificial region: possible predictor for delayed appearance of invasive intramural ureteric cancer.

Two cases of invasive lower ureteric cancer developed following frequent recurrence of superficial bladder tumors in the region of the ureteral orifice. The cancer focus could not be identified in the intramural ureter prior to intravenous urography which revealed hydronephrosis. When bladder tumors repeatedly develop near the ureteric orifice, careful investigations such as ureteral catheterization with a small brush for cytology or ureteroscopy are necessary for the early detection of invasive disease.