Differential diagnosis of non-atherosclerotic left main coronary artery stenosis.

A left main coronary artery (LMCA) stenosis without any atherosclerotic changes elsewhere in the coronary artery tree is a rare finding, and some uncommon reasons for luminal narrowing should be considered. An unusual case of non-atherosclerotic LMCA stenosis is reported.A middle-aged patient presented with acute myocardial infarction. An immediate coronary angiography was ordered and revealed a subtotal mid LMCA stenosis. A drug-eluting stent was successfully implanted in the LMCA.Operative revascularisation was recommended. Routine surgery was performed and surprisingly revealed an extended mass of a mediastinal tumour surrounding the aortic root. Histopathological examination of the tumour revealed a poorly differentiated squamous cell carcinoma.Postoperatively, the patient was treated with chemotherapy (carboplatin and docetaxel). Five years after the first admission to our hospital, the patient died as a result of ventricular fibrillation.The differential diagnosis of non-atherosclerotic LMCA stenoses is discussed.