Tubulovillous adenoma of the urinary bladder.

We report a case of vesical tubulovillous adenoma that occurred in a background of protracted chronic cystitis with intestinal-type glandular metaplasia and extensive cellular atypia (dysplasia) in the flat mucosa. Flow cytometry analysis showed DNA aneuploidy in the adenoma. Increased expression of the tumor suppresser gene, p53, and also of cellular proliferation markers (proliferating cell nuclear antigen and MIB-1) were detected in the villous adenoma and in the dysplastic regions of the flat metaplastic mucosa. These findings provide insight into the biology of intestinal metaplasia and also lend support to the theory of the chronic irritation-metaplasia-dysplasia-carcinoma sequence.