Ovarian extraembryonal teratoma. I. Endodermal sinus tumor.

Forty-one cases of pure endodermal sinus ovarian tumors are reported. The extraembryonal nature of this tumor is supported with comparative studies utilizing early human implantations. The clinical picture is one of a virulent malignancy occurring in young women, and although the tumor is commonly unilateral and encapsulated at the time of initial diagnosis, the outcome is almost always fatal. Experience with different therapeutic modalities is limited, but there is significant evidence that vigorous combination chemotherapy will improve the therapeutic outcome.