Intracranial germ-cell tumors. Immunohistochemical study of three autopsy cases.

Histological and immunohistochemical findings in three cases with primary intracranial germ-cell tumors are reported. Based on histological examination, they were diagnosed, respectively, as an endodermal sinus tumor with immature teratoid differentiation, teratoma and embryonal carcinoma, and choriocarcinoma and germinoma. The first case was presumed to be a combination of endodermal sinus tumor and germinoma. An immunohistochemical examination showed positive reactions to alpha-fetoprotein (AFP) and carcinoembryonic antigen (CEA) in the endodermal sinus tumor, and to human chorionic gonadotropin (HCG) in the choriocarcinoma, but showed no reaction in the embryonal carcinoma. Human chorionic gonadotropin was demonstrated in syncytiotrophoblastic cells and CEA in a gland-like structure. The value of measuring CEA in cases of germ-cell tumors, in addition to AFP and HCG assays, is stressed, and the characteristics of CEA-positive tissue are discussed.