Prostatic transitional cell carcinoma: concept of its pathogenesis and classification.

An updated comprehensive classification of transitional cell carcinoma (TCC) of the prostate is presented in accordance with the current nomenclature, which is based mainly on the theory of multifocal origin of urothelial neoplasms. TCC of the prostate is classified as being primary, secondary (synchronous and metachronous) or mixed (TCC associated with adenocarcinoma). The case histories of six patients with TCC of the prostate are presented. One patient had primary TCC of the prostate without evidence of urothelial carcinoma elsewhere; one patient had primary mixed TCC associated with separate foci of adenocarcinoma; and four patients had secondary TCC either synchronously or metachronously with foci of carcinoma elsewhere in the urothelium. The importance of considering TCC of the prostate as a well-defined clinicopathological entity is discussed.