Proliferative pattern of exophytic and superficially invasive and noninvasive low-grade urothelial carcinomas

In urothelial low-grade carcinomas of the bladder stage pT1, prognosis in g eneral is good. In a subset of these tumors infiltrating beyond the lamina muscularis mucosae, prognosis clearly worsens. Unfortunately, evaluation of the lamina muscularis mucosae often is very difficult or even impossible b ecause of its incomplete extension. In an immunohistochemical study on 131 pTa and pT1 urothelial tumors without provable lamina muscularis mucosae, w e evaluated the proliferative activity with the monoclonal antibody MIBI an d the expression pattern of cytokeratins of high molecular weight with the monoclonal antibody 34 beta E12. The highest proliferative indices were fou nd in tumors with a diffuse expression pattern of MIB-1 and 34 beta E12. A preliminary analysis of follow-up data showed that 70.6% of the pT1 GIb-GII a tumors that recurred showed a diffuse expression pattern for both markers . Whether these patients are candidates for a closer follow-up or even for a more radical therapy has to be subject to further follow-up studies. HUM PATHOL 30:145-150, Copyright (C) 1999 by W.B. Saunders Company.