[Choriocarcinoma of the stomach]

A 55-year-old Japanese man was admitted to our hospital in January 1985 complaining of epigastralgia. Radiologic and endoscopic examinations showed gastric carcinoma, but biopsy specimens taken by surgery showed the histologic pattern of choriocarcinoma. On autopsy, multiple metastatic sites wer observed, and histological examination of the primary and metastatic sites revealed choriocarcinoma. Primary gastric choriocarcinoma may develop from gastric cancer by retrodifferentiation.