Large mediastinal mass secondary to an aortocoronary saphenous vein bypass graft aneurysm.

A case of a 62-year-old man with a large mediastinal mass who had undergone aortocoronary bypass grafting 17 years earlier is presented. Computed tomography showed a 13-cm extrinsic cystic mass believed to represent a pericardial cyst or teratoma. Intraoperatively, the patient was noted to have an aneurysm of his right coronary artery bypass graft. We were able to find 4 other cases seen in this manner.