Teratoma

The PA radiograph (left panel) demonstrates a mass to the right of the trachea (arrow). Both the hilum and spine are well seen, suggesting that the mass may be anterior. A CT scan obtained just above the level of the right pulmonary artery (right panel) demonstrates an anterior mediastinal mass with multiple distinct densities. The rounded area of low attenuation in the middle of the mass indicates the presence of fat and is highly suggestive of a teratoma.