A case of teratoma with malignant transformation in the anterior mediastinum

: A 32-year-old woman was admitted to our hospital complaining of anterior chest pain for 3 months. Chest radiograph revealed a 30-mm mass in the anterior mediastinum. Contrast-enhanced CT scanning revealed a nonhomogeneous cystic mass with a fat or oil component and a thick wall with calcifications. The mass seemed to have invaded the pericardium and great vessels. Thoracotomy demonstrated hairs in the cystic lesions, with hard components that invaded the pericardium and great vessels. Due to extensive vascular invasion, the mass was incompletely resected. Pathologic examination demonstrated the presence of adenocarcinoma, so we diagnosed this case as teratoma with malignant transformation.