[Increased risk of tumor development in the upper urinary tract following multicentric papillary bladder tumors].

Two theories of pathogenesis of multifocal transitional cell carcinoma are discussed: 1. Theory of cellular implantation; 2. multifocal tumor growth. The increased incidence of tumors in the upper urinary tract after urinary diversion for bladder cancer supports the multifocal theory. After treatment of papillary bladder cancer the risk of developing a second tumor in the kidney or ureter is much higher. Therefore we emphasize the continuous follow-up with radiological control of the upper urinary tract.