Urothelial carcinoma of the prostate.

Urothelial carcinoma is a rare type of prostatic carcinoma which as a rule bears an unfavourable prognosis. In our material it comprises 4.5% of all prostatic carcinomas. It can occur isolated in the prostate as well as in connection with a urothelial carcinoma of the urinary bladder, which may have directly infiltrated the prostate. Almost one-third of our cases are combined with an ordinary carcinoma of the prostate. The majority of pure urothelial carcinomas, with or without bladder involvement, are found in stages 0-B (59 of 68 cases). When combined with an ordinary prostatic carcinoma, most urothelial carcinomas (20 of 29 cases) are present in stages C and D. Independent of bladder involvement, 24 urothelial carcinomas are grade II and 86 grade III tumours. Survival times range from 12 to 84 months (average 34.8 months) in grade II and from 1 to 103 months (average 29.5 months) in grade III carcinomas. Problems in differential diagnosis arise when urothelial carcinoma has to be distinguished from solid or, rarely, cribriform prostatic carcinoma. Diagnostic criteria for urothelial carcinoma are compact formations without stroma being sharply delineated from stroma, extensive ductal growth pattern with necroses of comedo type, high mitotic rates and perifocal inflammation.