Primary mediastinal sarcoma is rare, corresponding to less than 1% of all soft tissue sarcomas and less than 10% of all primary mediastinal tumors. A 52-year-old man with signs and symptoms of cardiac tamponade underwent echocardiography of the right ventricle, which revealed significant pericardial effusion and an extensive heterogeneous mediastinal mass measuring approximately 15 × 8 cm in the pericardial space in close contact with the right chambers and causing diastolic collapse. The diagnostic hypothesis was a pericardial or mediastinal […]