[Resection of mediastinal teratoma in a patient with cardiac tamponade due to pericardial perforation].

Benign teratoma of the mediastinum causes a variety of complications if left untreated, but reports of pericardial perforation have been rare. We report a case of mediastinal teratoma that perforated the pericardium and induced clinical cardiac tamponade. The patient was a 46-year-old male, who was admitted due to sudden chest pain. Since chest CT and echocardiography suggested perforation of the pericardium by a mediastinal teratoma, pericardial drainage was carried out. However, heart failure could not be resolved, and the tumor was resected on the 5th hospital day. From the intraoperative and pathologic findings, mature type mediastinal teratoma was found to have perforated the pericardium, causing massive influx of yellowish fluid from the cyst of the tumor. There have been only 10 cases reported to date in Japan and abroad in which mediastinal teratoma was complicated by cardiac tamponade.