Primary Extraskeletal Osteosarcoma in the Anterior Mediastinum: A Case Report and Review

ABSTRACT

Extraskeletal osteosarcoma (ESOS) is a malignant soft tissue neoplasm producing osteoid, without any continuity with the bone or periosteum. Primary ESOS presenting in the mediastinum is an extremely rare, yet aggressive malignant tumor associated with a poor prognosis. We report a case of primary ESOS arising from the thymus in a 63-year-old male patient.