Primary gastric choriocarcinoma associated with adenocarcinoma－A Case Report with Immunohistochemical Study－

A case of a 69 year old female with primary gastric choriocarcinoma was presented with spesial reference to histogenesis by using the immunohistochemical tequnique (PAP method). The gastric tumor in this case was histologically diagnosed as choriocarcinoma coexistent with adenocarcinoma. From hormonal standpoint, the diagnosis was confirmed by recognition of high HCG titers in both the serum and tumor. The primary focus of the choriocarcinoma was detected neither in the genitourinary tract nor in the mediastinum in spite of a thorough autopsy. By PAP method tumor cells of choriocarcinoma showed high positive reaction only to anti-HCG antiserum and less positive to anti-HPL and SP1 antisera in contrast to those of uterine choriocarcinoma with high positive reaction to anti-HCG, HPL and SP1 antisera. Tumor cells of adenocarcinoma showed positivity to anti-CEA and anti-AFP antisera by the same method. These results indicate that gastric choriocarcinoma might be functionally defferent from gestational choriocarcinoma. Moreover, tumor cells of adenocarcinomatous lesion have some resemblance to embrynal carcinoma morphologically and immunohistochemically. Therefore, the origin of gastric choriocarcinoma seemed to be morphological retrodifferentiation of tumor cells to embryonal ectoderm such as trophoblastic cells.

choriocarcinoma

adenocarcinoma

stomach

immuoohistochemistry

histogenesis