Elevated prostate markers in metastatic small cell carcinoma of unknown primary.

Numerous ectopic hormones and markers have been described in small cell carcinoma of the lung as well as in extrapulmonary small cell carcinomas. The authors report a case of a patient with metastatic small cell carcinoma of unknown primary who had very high prostatic acid phosphatase (PAP) and prostatic specific antigen (PSA) levels. Results of multiple prostate examinations, as well as blind biopsies, were normal. His course was significantly longer than that of the usual patient with extensive small cell carcinoma. At autopsy the prostate showed only mild benign prostatic hypertrophy. There are no previous reports in the literature of abnormal prostate markers in small cell carcinomas. Physicians should be aware of the increasing complexity and the unusual biologic markers associated with neuroendocrine carcinomas. In some of these cases, the tumors ability to produce an ectopic product may portend an improved prognosis.