Immunoreactive prostatic specific antigen in male periurethral glands.

Prostatic specific antigen (PSA) is considered an antigen unique to benign and malignant prostatic tissue. Recent evidence in the literature has raised serious doubts about the specificity of this antigen. In this study twenty male urethral specimens were evaluated for PSA and prostatic acid phosphatase (PAP) from patients without evidence of prostatic cancer. Eight of these 20 urethral specimens exhibited strong immunostaining for both PSA and PAP, localized in the periurethral glands. Five of the 17 urethral biopsies were positive for both antigens, while all three of the whole mount autopsy specimens stained positive for PSA and PAP. Within the autopsy series, there was heterogenous staining of the periurethral glands within the same specimen. This evidence disproves the fact that PSA and PAP are organ specific as previously described. More than likely any tissue of cloacal origin has potential for staining positive for prostatic specific antigen and prostatic acid phosphatase.