Adenoid cystic carcinoma of the prostate. A case report with immunoperoxidase staining for prostate-specific acid phosphatase and prostate-specific antigen.

Adenoid cystic carcinoma occurs most commonly in the major and minor salivary glands, but also has been recognized in numerous other locations. Adenoid cystic carcinoma of the prostate gland is, however, extremely uncommon with only two other reported cases. The authors have studied a case of adenoid cystic carcinoma of the prostate with immunoperoxidase staining for both prostate-specific acid phosphatase and prostate-specific antigen, which have been shown to be specific for normal prostatic epithelium and prostatic carcinoma. The negative staining for these antigens in this tumor distinguishes adenoid cystic carcinoma from the usual acinic adenocarcinomas of the prostate, and suggests an origin from periurethral glands or metaplastic urethral mucosa.