[Histomorphological variants of carcinoma in situ of the urinary bladder]

31 secondary carcinomas in situ of the urinary bladder have been histologically examined. They exhibit a great variability of their histological features. This is due to the varying rate at which cells lose their specific properties. Besides urothelial carcinomas in situ, a squamous cell carcinoma in situ as well as the intraurothelial formation of malign signet-ring cells have been detected.