Mass Confusion

A 64-year-old woman presented to a district general hospital with left-sided chest pain that radiated through to the back. Her medical history included a previous myocardial infarction. After assessment in the emergency department, acute aortic dissection was suspected, and a computed tomography (CT) aortogram was performed (Figure, A). This aortogram did not demonstrate evidence of acute aortic pathology. However, a soft-tissue mass was visualized in the left upper mediastinum adjacent to the distal aortic arch, suggestive of either an inflammatory process or a neoplastic lesion.She was referred to our center for further investigation. A CT-guided biopsy of the mass was scheduled ≈4 weeks after initial presentation. In view of her history of ischemic heart disease, she …