[Spindle Cell Sarcoma Originated in the Anterior Mediastinum;Report of a Case].

An anterior mediastinal sarcoma is a very rare type of mediastinal tumor. A 45-year-old female visited our hospital with swelling in the right anterior chest wall. Radiographically, the tumor was found to originate from the thymus and to infiltrate to the major pectoral muscle through the 1st intercostal space. Positron emission tomography revealed fluorodeoxyglucose accumulation at a standardized uptake maximum value of 16.1. Percutaneous needle biopsy showed the pathological findings of sarcoma. The tumor was resected along with the thymus and chest wall tissues including the right hemi-manubrium of the sternum, clavicle head, 1st and second ribs, and major pectoral muscle. After 4 months, tumor relapse occurred at the site of needle biopsy and additional resection was performed. At 10 months after the 2nd surgery, the patient was free from disease. From histologic and immunohistochemical findings, the tumor was diagnosed as spindle cell sarcoma.