[A case of mediastinal immature teratoma with elevated levels of CA19-9].

A 15-year-old woman was found to have a large anterior mediastinal mass on chest roentgenogram. Preoperatively, serum levels of CA19-9 were found to be elevated. From the result of pathological study on the resected lesion, it was diagnosed as immature teratoma. The fluid levels of CA19-9 extracted from the tumor were found to be elevated. Part of the tumor, the pancreas, the bronchial epithelium and the intestinal epithelium, were shown positive staining in immunoperoxidase assay using anti CA19-9 antibody. The postoperative course was satisfactory and the serum levels of CA19-9 returned to normal. In mediastinal germ cells tumors, there are no cases reported in which CA19-9 was detected in serum and in the tumors. In order to define the relation between mediastinal germ cell tumors and CA19-9, further more cases should be investigated.