[Mucinous adenocarcinoma of the prostate: a case report and review of 32 cases on immunohistochemical study of both PSA and CEA].

Mucinous adenocarcinoma of the prostate is extremely rare and its biological behavior is not well known. We report a case of mucinous adenocarcinoma of the prostate which stained positively for prostate specific antigen (PSA) and negatively for carcinoembryonic antigen (CEA) on immunohistochemical study. Our case contained conventional adenocarcinomas and no signet-ring cells. Thirty two cases of mucinous adenocarcinoma of the prostate which performed on immunohistochemical study of both PSA and CEA, including our case, were reviewed. 17 of the 23 cases of immunoreactive to PSA contained conventional adenocarcinomas, and 3 of the 10 cases of immunoreactive to CEA contained them, respectively. The 6 cases of immunoreactive to CEA only contained signet-ring cells. It indicated that there seemed to be the two types of mucinous adenocarcinoma of the prostate, the one which stained positively for PSA was the subtype of conventional adenocarcinomas, and the other which stained positively for CEA and negatively for PSA was derived from the intestinal metaplasia with atypia of the prostatic urethra.