Abstract
A 46-year-old man who had got a bruise on the anterior thoracic region in a traffic accident at the end of June 2006 was seen at the hospital because of chest pain. Chest CT scan showed a 2.8×2.2cm tumor shadow in the anterior mediastinum as well as fracture of the sternum. Chest magnetic resonance imaging scan disclosed that fatty component was involved in the inner part of the tumor which was heterogeneously enhanced. Thus teratoma of the mediastinum was diagnosed. In November when the fractured portion of the sternum became stable, a total removal of the thymus and the mediastinal tumor was performed by median sternotomy. The removed material showed a usual type of mature teratoma and papillary glandular epitherium with a high-grade atypia inside of it. From these findings the definite diagnosis of mature teratoma of the mediastinum with malignant transformation to adenocarcinoma was made. The postoperative course was uneventful and the patient was discharged from the hospital on the 7th postoperative day. The patient has been recurrence free up to now and is under clinical observation.
In performing surgical therapy for a mature teratoma, we must keep a possibility of malignant transformation of it in mind, though it is rare.
