[A case of benign cystic teratoma growing in the thoracic cavity]

A case with benign cystic teratoma growing in the thoracic cavity, which is rare in Japan, in a 49-year-old woman is reported. She complained a chest pain suddenly. Chest X-ray examination revealed an abnormal shadow and pleural effusion in the right lung field. Chest CT scan and MRI disclosed a capsulated tumor in the thoracic cavity. During surgery the tumor had adhered to the part of the parietal pleura with no continuity with anterior mediastinum. The tumor measured 11.0 x 9.5 cm in size and was a mature cystic teratoma with pancreatic tissue, histologically. The fluid levels of amylase extracted from the tumor was highly elevated. Rupture due to autodigestion by pancreatic amylase of the tumor was supposed to be a cause of chest pain.