Left main coronary stenosis by a mediastinal lymphoma.

A 50-year-old patient presented with a 3-month history of chest pain, a pathological result on electrocardiogram stress test, and signs of coronary heart disease on myocardial scintigraphy. Coronary angiography showed an isolated, moderate tubular stenosis of the left main coronary artery. Coronary bypass surgery was carried out, and intraoperative examination revealed a mediastinal lymphoma which caused the stenosis of the left main artery by external compression.