Three cases of extrapulmonary small cell carcinoma occurring in the prostate, stomach, and pancreas.

Small cell carcinomas are fairly common neoplasms in the lung, but tumors featuring similar histological profiles may occur in extrapulmonary organs. Three cases of small cell carcinomas occurring in the prostate (case 1), stomach (case 2), and pancreas (case 3) are presented. Production of hormones was demonstrated immunohistochemically in all cases. In case 2 alpha-fetoprotein (AFP) was elevated in the serum and observed immunohistochemically in tumor cells. Production of AFP is a distinctive feature, which has not been reported in the pulmonary and extrapulmonary cases of small cell carcinoma. Amplification and/or expression of myc gene family have been suggested to be related to the prognosis of pulmonary small cell carcinoma. Amplification of myc genes was not detected in any of our cases, but c-myc protein was demonstrated immunohistochemically in tumor cells of case 1.