Three cases of poorly differentiated endometrial adenocarcinoma showing trophoblast-like differentiation are reported. The multinucleated, syncytiotrophoblast-like cells were strongly positive for &human chorionic gonadotropin (B-HCG) by immunohistochemical study. High levels of &HCG were also present in the patients' serum, but dropped significantly after treatment. The patients had an unusually rapid and progressive clinical course with widespread dissemination and death by tumor. Cancer 68:1799-1802,1991.
ARCINOMAS in which trophoblastic components C (syncytiotrophoblast and cytotrophoblast) are present are rarely found in extragenital organs, such as stoma ~h , ' -~ large inte~tine,~ and urinary bladder.5 p-Human chorionic gonadotropin (P-HCG) production can be demonstrated immunohistochemically in such cases, and high concentrations of 0-HCG are usually present in the serum of these patients. Occasionally, tumors at different sites may show partial trophoblastic differentiation, with only syncytiotrophoblast or cytotrophoblast present.' In the female genital tract, these neoplasms are extremely rare, with only two cases of endometrial adenocarcinoma'.' and one of ovarian carcinosarcoma* with trophoblastic differentiation having been described.
We studied three cases of endometrial adenocarcinoma with choriocarcinomatous differentiation. The areas of choriocarcinoma included p-HCG-positive syncytiotrophoblast-like cells; high levels of P-HCG could be detected in the serum of the patients. The tumors followed an unusually aggressive behavior with poor patient outcome. These cases constitute the basis of our report.