[Matured mediastinal teratoma with high levels of tumor markers in cystic fluid].

A 42-year-old woman was admitted to Gifu Municipal Hospital because of an abnormal mediastinal shadow on a chest X-ray film. The serum CA125 level was slightly high 38 U/L, normal: < 35 U/L. Preoperative examination of fluid from a cyst revealed a high level of carcinoembryonic antigen (550 ng/ ml). The tumor resected was 11 x 9 x 5 cm. Microscopic examination revealed a matured teratoma containing pancreatic cells, collagenous tissues, squamous epithelia, and hair follicle-like tissues. Biochemical analysis of the cystic fluid revealed high levels of eight tumor markers: carcinoembryonic antigen, CA125, CA19-9, SLX, Ferritin, NSE TPA, and elastase 1. Samples stained positively for the tumor markers carcinoembryonic antigen CA125, CA19-9, and NSE by ABC immunohistochemical staining. The serum carcinoembryonic antigen levels had decreased to the normal level within two weeks after the surgery. The high levels of tumor markers and materials in the cystic fluid may have been related to the biological characteristics of the various cell components in this matured teratoma.