A large ovoid uniformy soft tissue opaque mass lesion is seen cranial to and border effacing with the cardiac silhouette, approximately 3 intercostal spaces in width and equal to the height of the cardiac silhouette. Dorsal and slight rightward displacement of the trachea is noted level with the mass lesion. The cranial mediastinum presents approximately 3 times the width of the vertebral bodies at the same level.  The lung parenchyma presents a mild overall increase in opacity, due to the readout algorithm with marked edge-enhancement. Multiple pulmonary osteomas are seen. There is no evidence of metastatic spread to the lungs and no evidence of esophageal dilation.