Choriocarcinoma of Stomach
A focus of cytotrophoblast and intermediate trophoblast is surrounded by conventional adenocarcinoma. Primary gastric choriocarcinomas do occur but are exceedingly rare. They are almost always associated with adenocarcinoma. The histologic and immunohistochemical features are identical to those arising in the gonads. Serum HCG levels are usually elevated. Prognosis is extremely poor.