Extraskeletal osteosarcoma arising in anterior mediastinum: brief report with a review of the literature.

Extraskeletal osteosarcoma arising from the mediastinum is an extremely rare malignant tumor. We present the case of a 77-year-old woman with a past history of pulmonary tuberculosis who presented with a dyspnea. Imaging studies revealed a huge anterior mediastinal mass with scattered calcifications. Complete surgical resection was successfully performed, and histologically the tumor contained osteoid formation consisting of round atypical cells. The literature concerning this rare tumor is reviewed.