Thrombosed right coronary artery aneurysm presenting as a myocardial mass.

A coronary artery aneurysm is defined as coronary dilatation that exceeds the diameter of normal adjacent artery segments, or is 1.5 times the diameter of the largest coronary artery. Coronary artery aneurysms are rare with an incidence of between 1.5% to 5%. The aneurysm is caused by destruction of the vessel media, thinning of the arterial wall, increased wall stress, and progressive dilatation of a segment of the coronary artery. The most common cause is atherosclerotic coronary artery disease. These aneurysms occasionally rupture but more commonly develop thrombus and hematoma leading to the appearance of the presence of an intramyocardial mass. We present the case of a 60-year-old man with hypertension who presented with a mass that was identified initially by transthoracic echocardiography in the setting of an inferior wall myocardial infarction, which was later recognized to be a thrombosed right coronary artery aneurysm.