The patient was seeking medical advice complaining of respiratory symptoms. Chest CT without contrast was done and revealed a right lung consolidation and mediastinal mass. The initial clinical differential diagnosis list did not include an aneurysm. A contrast study was performed a few hours later, which lead to the diagnosis of an aortic arch aneurysm and a possible leak.

Unfortunately, we were informed later by the referring physician that the patient had died a few hours later.

This is likely a false rather than a true aneurysm because the aortic arch itself is not widened and the mural calcifications are not changed in location, i.e. the vessel wall is unchanged in position. Also there is a communicating defect in the right wall of the arch resulting in aneurysm formation.

This case illustrates that an aneurysm should be included in the differential diagnosis of a mediastinal lesion.