Purpose: Mucosal migration of transitional cell carcinoma in situ is a potential mechanism for multifocal lower tract disease.
Materials and methods: The clinical course and pathological studies of 8 cases of carcinoma in situ are reviewed in detail.
Results: The pattern of disease of carcinoma in situ of seminal vesicle provides circumstantial evidence for mucosal migration of cancer from a bladder or prostatic urethral origin.
Conclusions: A monoclonal origin of bladder cancer combined with mucosal spread of carcinoma in situ suggests that incomplete destruction of carcinoma in situ may adversely affect long-term results by permitting extension into the distal ureters, prostatic duct or seminal vesicles. Protracted intravesical treatment of carcinoma in situ without complete elimination of the disease allows the natural history of mucosal spread to become evident.