[A case of endodermal sinus tumor in the basal ganglia associated with Down's syndrome].

A case of Down's syndrome accompanied by endodermal sinus tumor of the left basal ganglia is reported. She was referred to us because of right hemiparesis. A CT scan showed a calcified mass in the left basal ganglia, which was well enhanced on contrast CT. Emergency removal of the tumor was performed because of its rapid growth, intratumoral hemorrhage, and acute hydrocephalus. The histological diagnosis established after surgery was endodermal sinus tumor. Alphafetoprotein-positive cells were seen in the resected tumor by light microscopy. Postoperative irradiation was very effective, and the high level of serum alphafetoprotein decreased during the course of irradiation. The residual tumor, enhanced on contrast CT, was treated by administration of cisplatin and etoposide after irradiation. Cases of malignant tumors other than leukemia, which are associated with Down's syndrome, are extremely rate. To our knowledge, including three cases of germ cell tumor, there have been only nine cases of brain tumors associated with Down's syndrome reported previously.