Prostatic adenocarcinoma with urothelial (transitional cell) carcinoma features.

Prostatic adenocarcinoma and urothelial carcinoma (transitional cell carcinoma) may coexist in the prostate. However, a carcinoma with mixed features has not been recognized. Four cases, three surgical pathology cases and one autopsy case of prostatic adenocarcinoma with urothelial carcinoma features, were retrospectively found in a urological pathology teaching file maintained from 1984 to 1993. Subsequently, 181 consecutive cases of radical prostatectomy from 1994 to 1999 were reviewed, and two prostatic adenocarcinoma areas with features of urothelial carcinoma were identified. Areas with urothelial carcinoma features were identified in the intraductal component of the carcinoma in five cases and in the invasive component in three cases. The intraductal carcinoma with urothelial carcinoma areas usually merged with regions of prostatic adenocarcinoma with a papillary or cribriform pattern. All prostatic adenocarcinomas having areas with urothelial carcinoma features were of high stage, and five of six cases had ductal features. The urothelial carcinoma component displayed a positive reactivity for thrombomodulin and negative or weaker reactivity for PAP and PSA than the prostatic adenocarcinoma component in the same tumor. Excluding the case noted at autopsy, all patients died of the disease within 3 years. Urothelial carcinoma features were usually associated with ductal carcinoma of high stage. Areas of prostatic adenocarcinoma with urothelial carcinoma features should be considered histopathologically as areas of mixed carcinoma of the prostate. Prostatic adenocarcinoma with areas of urothelial carcinoma features may pose a difficult differential diagnosis problem with urothelial carcinoma, especially with small biopsies with focal weak immunoreactivity for PAP, PSA, and thrombomodulin.