Primary Thymic Adenocarcinoma with Production of Carbohydrate Antigen 19-9 and Carcinoembryonic Antigen

A 59-year-old male, whose chest X-ray showed an abnormal shadow, visited us for further study. Laboratory examination showed the elevated level for both carbohydrate antigen 19-9 (CA19-9) and carcinoembryonic antigen (CEA) in serum, and the chest X-ray and computed tomography showed an anterior mediastinal mass. Under a diagnosis of thymic malignancy, extended thymectomy with combined resection of the pleura and pericardium was performed. Histopathological findings showed a well-differentiated adenocarcinoma of the thymus, in which CA19-9 and CEA were positive immuno-histochemically. The level of serum CA19-9 and CEA returned to normal ranges postoperatively, however, the tumor recurred in local site with re-elevation of these tumor markers at the 20th month after surgery. He died at 4th month after the first recurrence despite the intensive chemotherapy. We report an extremely rare case of primary thymic adenocarcinoma with the production of CA19-9 and CEA.