33 years after vesiculography using the X-ray contrast remedy Thorotrast on transurethral way in a patient with chronic prostatitis a carcinoma developed in the region of the vesical neck. Histologically the tumour imposed now as a differentiated urothelium carcinoma of medium degree. By autoradiography in the region of the tumour structures radioactive Thorotrast could be proved. On account of the close topographical relations and the long time of latency the development of the carcinoma seems to be ascertained by the then application of Thorotrast. The connections are discussed.
