[Several comments and various considerations on Von Brunn nests]

Subsequent to a certain amount of aggression, the vesical epithelium can induce some histological changes which would range from the most innocent morphological vicarious forms to the most aggressive neoplastic types (transitional, squamous and/or glandular tumours). Co-existence in the same urothelium of metaplastic, dysplastic and/or neoplastic lesions should not therefore be a surprise. With the intention of assessing the urothelium evolutive potential, we present a morphological study of the male cervix-trigonal epithelium abnormally involved in the steroidal hormones immunosuppression and actions. The typical patches of "female cervical trigonitis" have not been seen in this epithelium although there has been a wide range of evolutive possibilities of squamous and/or glandular lineage. Both tissular options have a clear metaplastic etiology. They present neither atypia not dysplasia, but participate of the distinctive dynamics of Von Brunn nidi. (C. Pellicé Jr: Doctorate Thesis, 1990). Of all the various evolutive options displayed by the urothelium when subjected to aggression, this study will focus on the Von Brunn nidi because of their atypical behaviour, their peculiar histogenesis and their dubious and controversial participation in vesical carcinogenesis.