A Giant Left Circumflex Artery Aneurysm with Thrombosis Formation Presenting as a Left Atrioventricular Groove Mass.

A coronary artery aneurysm is defined as the dilation of a coronary artery segment that is 1.5-fold the diameter of the neighboring normal segments. A patient with a history of aortic valve replacement and coronary artery bypass graft surgery, transthoracic echocardiography revealed a large mass with an echolucent center in the left atrioventricular groove. Transesophageal echocardiography showed that the left atrial appendage was free of thrombosis, and there was a mass with an echolucent center beneath the left atrial appendage, suggestive of aneurysmal dilation in the left circumflex artery with thrombosis formation Coronary artery computed tomography angiography confirmed this finding. In patients with or without a history of coronary aneurysms, the presence of a mass in the atrioventricular groove on echocardiography should alert clinicians about the presence of a coronary artery aneurysm with thrombosis formation as a probable etiology.