Choriocarcinoma of the stomach: pathogenesis and clinical characteristics.

A patient with primary choriocarcinoma of the stomach is reported. Abdominal pain, weight loss, a palpable epigastric mass, and gastrointestinal bleeding are the most common clinical features of this germ cell tumor, making it difficult to distinguish choriocarcinoma from primary adenocarcinoma of the stomach. The unique aspect of this case is the mixed histology of this rare neoplasm, containing both adenomatous and embryonal carcinoma, in addition to the choriocarcinoma. We believe that this unusual tumor probably results from dedifferentiation of primary adenocarcinoma of the stomach. On the average, patients with this disease live less than 2 months from the time of diagnosis, and treatment with combination chemotherapy has not improved the survival.