Prostate cancer with a normal PSA: small cell carcinoma of the prostate--a rare entity.

Pure small cell carcinoma of the prostate is extremely rare. When it does occur, it is usually in concordance with prostatic adenocarcinoma. Early diagnosis is difficult as the carcinoma tends to spread early to visceral organs without concordant elevation of prostate-specific antigen (PSA). Because this condition is rare, no standard treatment regimen has been established, and the overall prognosis remains poor. This case report describes clinical characteristics of a 67-year-old man with pure small cell carcinoma of the prostate. The unique clinical and biological features of this histologic type of prostate cancer are discussed.