[A case of small cell carcinoma of the prostate]

A case of a small cell carcinoma of the prostate that occurred in a 68-year-old man is reported. Needle biopsy of the prostate showed an adenocarcinoma. A second biopsy revealed both an adenocarcinoma and a small cell carcinoma. A subsequent third biopsy revealed only a small cell carcinoma, and the patient died of respiratory failure 26 months after the initial presentation. An autopsy revealed the tumor that had replaced the prostate extended into the bladder and rectum. Widespread metastatic foci, showing a histologic pattern of solely a small cell carcinoma, were present in various organs. The adenocarcinoma component was seen restricted to the prostatic region. Immunoperoxidase staining for prostate-specific antigen, prostate-specific acid phosphatase, gamma-seminoprotein, and leu-7 showed positivity only in the adenocarcinoma, whereas neuron-specific enolase was positive only in the small cell carcinoma.