[A case of primary posterior mediastinal chordoma].

A 49-year-old man, with a tumor shadow overlapping the heart on chest X-ray film was followed for 5 years. He was admitted because the tumor shadow enlarged. Chest CT scan showed a 6 x 7 cm in diameter extrapulmonary tumor at the Th8 and Th9 level, and a defect of the anterior margin of the thoracic vertebra is observed. Because thoracic CT-guided needle biopsy was not successful, total resection combined with thoracic vertebrae was performed. The tumor was under the parietal pleura and did not involve into the intrathoracic organs. Histological examination showed small round cells arranged in sheets and cord-like fashion in a mucinous stroma. On immunohistochemistry, the tumor cells were positive for S-100 protein, vimentin, AE1/3. CAM5.2, EMA and Alcian blue staining. Thus, we confirmed the diagnosis of chordoma. Chordoma is a rare malignant bone tumor that originates from notochordal remnants and accounts for about 1-4% of all malignant bone tumors. Intrathoracic mediastinal chordomas is extremely rare, representing only 3% of all chordomas.