A 62-year-old woman with a history of dyslipidemia and hypothyroidism was referred to our institution with syncope. Cardiac tamponade due to spontaneous rupture of a 50-mm aneurysm of the coronary artery was diagnosed by transthoracic echocardiography, enhanced computed tomography, and coronary angiography. Emergency surgery was performed, and despite developing postoperative complications such as acute renal insufficiency, the patient was discharged from hospital without sequelae 89 days later. Histological findings revealed cystic media degeneration, but neither significant atherosclerotic changes nor inflammatory cell infiltration. Although coronary artery aneurysms are comparatively rare and generally asymptomatic, those over 30 mm in diameter are considered to be at increased risk of rupture. A coronary artery aneurysm of about 50 mm ruptured in our patient, supporting this view.
Keywords: Cardiac tamponade; Cystic media degeneration; Giant coronary artery aneurysm.