Image Description
Microscopic Features: Inverted urothelial papillomas (IUP) commonly show solid nests with microcysts and pseudoglandular spaces (shown here) containing eosinophilic colloid material. The gland-like spaces are lined by the same urothelial cells like the rest of the tumor. Uncommonly, however, there is true glandular differentiation (next image). The glandular variant of IUP may closely mimic florid cystitis cystica and cystitis glandularis. The diagnosis of IUP in such cases rests on the overall architecture of the lesion.