Adenocarcinoma arising in anterior mediastinal mature cystic teratoma: Report of a case

Mediastinal mature teratoma with malignant components is a very rare condition. A 57-year-old man presented with a large (14 × 10 cm) encapsulated and lobulated cystic mass involving the anterior mediastinum. The most consistent diagnosis on the basis of radiological findings was mature cystic teratoma, and a surgical resection was thus indicated. The operation was performed through a median sternotomy, and the tumor was extirpated with a combined resection of the pericardium and left mediastinal pleura. Although the pathological diagnosis was mature cystic teratoma, this patient showed a recurrence of malignant effusion 7 months following the operation. The earlier resected specimen was pathologically re-reviewed according to the blocked entire mass, and small foci of adenocarcinoma were thus found within the tumor.