Mucinous adenocarcinoma of the prostate gland.

Mucinous adenocarcinoma of the prostate gland is one of the least common morphologic variants of prostatic carcinoma. A lack of precision in the definition of these mucinous neoplasms has resulted in reports which have overstated the incidence of this lesion. Of approximately 1,600 carcinomas of the prostate gland seen at Memorial Hospital from 1963 to 1983, excluding cases with only needle biopsy material, six mucinous prostatic adenocarcinomas were identified. Mucinous prostatic carcinomas were diagnosed when at least 25% of the resected tumor contained lakes of extracellular mucin, and an extraprostatic tumor site was ruled out. In five of the six cases, a cribriform pattern predominated in the mucinous areas. All of the mucinous prostatic tumors had prostate-specific acid phosphatase (PSAP) and prostate-specific antigen (PSA) immunoreactivity. Our experience and our review of the literature indicate that these tumors do not respond well to hormonal therapy. Contrary to prevalent opinion, they have an aggressive biologic behavior and, like nonmucinous prostate carcinomas, have a propensity to develop bone metastases and increased serum acid phosphatase levels with advanced disease.