Mediastinal mature teratoma with elevated serum CA19-9 levels ; a report of two cases

We treated two patients with mediastinal mature teratoma with elevated serum CA19-9 levels. One was a 24-year-old woman, who consulted us, complaining of fever, cough and anterior chest pain. Her chest X-ray showed an abnormal mediastinal shadow. Her serum CA19-9 level was 958.0 U/ml, but AFP, HCG and CEA were normal. The other was a 23-year-old man who consulted us because an abnormal shadow had been found in a chest X-ray film taken during a routine physical check up. His serum CA19-9 level was 47.5 U/ml. Chest CTs of both patients showed cystic masses in the anterior mediastinum. we operated on both patients. Histological examination revealed a cystic mature teratomas, both contained pancreatic tissue. Postoperatively, their serum CA19-9 levels returned to normal. Immunohistological examinations showed strongly positive CA19-9 staing demonstrated in the pancreatic duct and the epithelium of the cysts. We conclude that CA19-9 may be helpful in the diagnosis of teratomas, but cannot determine whether they are benign or malignant.