Spontaneous rupture of the ascending thoracic aorta resulting in a mimicking pseudoaneurysm.

We report on the rare and successful surgical treatment of a case of spontaneous rupture of the ascending thoracic aorta resulting in a mimicking pseudoaneurysm. A 72-year-old male who had complained of sudden onset of severe chest pain was admitted to our hospital. Initially, acute type A closing aortic dissection was suspected because computed tomography (CT) showed a small ulcer-like projection (ULP) in the posterior aspect of the ascending aortic wall, but it also revealed no intimal flap, false lumen or aortic aneurysm. CT and magnetic resonance imaging (MRI) indicated a change in the radiographic aspect of the ULP and revealed a mimicking saccular-type pseudoaneurysm and gradual increasing size of the pseudoaneurysm. Surgery was performed after considering the risk of pseudoaneurysmal rupture. We replaced the ascending aorta and diagnosed it as a spontaneous aortic rupture by histological examination of the rupture site after failing to observe an aneurysm or dissection. We discuss these results with reference to the literature, including our pathological and radiographical findings.