Annuloaortic ectasia, cystic medial degeneration of the afflicted aortic wall leading to progressive dilatation, is often accompanied by Marfan's syndrome. Some portions of intimal flap is commonly demonstrated along the aorta in the noninvasive diagnosis of aortic dissection. We report the first case of circumscribed aortic dissection developed in a 28 year old obese non-Marfanoid patient. He was transferred after thrombolytic therapy at a community hospital because of severe chest pain and ST segment elevation. Transthoracic echocardiography showed markedly dilated aortic root, moderate amount of pericardial effusion, mild aortic regurgitation in spite of normal regional wall motion of left ventricle. Intimal flap, characteristic of aortic dissection, was not seen with computed tomography. Intimal tear was demonstrated just above aortic valve only by transesophageal echocardiography. Two parallel intimal tear and small circumscribed dissection was demonstrated by autopsy.