[A surgically treated case of saccular true aneurysms in the ascending aorta].

A surgically treated case of saccular true aneurysms in the ascending aorta caused by cystic medial necrosis is reported. A 59-year-old woman, who had no findings of Marfan syndrome, was admitted to our hospital because of chest discomfort and dyspnea on exertion. Echocardiography showed that massive pericardial effusion and the dilated ascending aorta without dissection. No aortic valve insufficiency nor dilatation of the Valsalva's sinuses were found out. Chest CT scan and aortography also revealed that focal dilatation of the ascending aorta without the intimal flap and the false lumen. Because of the presence of cardiac tamponade, we performed an emergency operation without definite diagnosis of the ascending aortic lesion. Intraoperatively, 2 saccular aneurysms, which were 55 x 45 x 20 mm and 25 x 15 x 15 mm in size, were found out in the ascending aorta. The ascending aorta was replaced with a woven Dacron graft successfully. These aneurysms were histologically diagnosed as true aneurysms caused by cystic medial necrosis. Although saccular true aneurysms of the ascending aorta are rarely observed, they should be considered as one of ascending aortic diseases that cause cardiac tamponade potentially.