Aneurysm of an aortocoronary saphenous vein bypass graft presenting as an anterior mediastinal mass.

Fifteen years after aortocoronary bypass surgery, a 52-year-old asymptomatic man was found to have a large anterior mediastinal mass. Angiographic studies showed no evidence that a vascular structure was responsible. At operation, a saphenous vein graft to the left anterior descending artery was found to be affected by a large thrombus-filled aneurysm. This is one of the few known cases in which such an aneurysm has presented as a mediastinal mass.