ARYA Atherosclerosis8320121002Diagnostic dilemma: Saccular aneurysm or pseudoaneurysm of the ascending aorta with dissection above level of leaflets439439ENMaryamMehrpooyaAssistant Professor, Department of Cardiology, School of Medicine, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran.. maryammehrpooya@yahoo.comMehrdadSalehiRaminEskandariZeinabShajiratAllahyarGolabchiMajidMazoochi201205282012080520120630BACKGROUND: In true aneurysm, the wall of aneurysm is composed of the normal histological components of aorta. A false aneurysm (pseudoaneurysm) represents a rupture which does not contain the normal histological components of aorta. It is a fibrous peel that has formed from a small perforation of aorta. We describe an unusual presentation that has signs which some of them are only manifested in true aneurysm and some others only in pseudoaneurysm. CASE REPORT: An 85-year-old man underwent elective coronary angiography for chest pain work-up. Our evaluation by invasive angiography and CT angiography showed aortic dissection. In surgery we found that dissection flap was composed of some parts of intima and media layers. These signs leaded to confusing symptoms. Localized bulging of ascending aorta had continued to brachiocephalic artery (transverse arch involvement). Dissection flap was composed of some part of intima and media layers. It was a strange case, it was not solely a perivascular hematoma and it did not have all three layers of aorta wall. Partial aorta replacement was performed. The operation and recovery was uneventful. CONCLUSION: This unusual presentation of disease has not been mentioned in literatures. Our experience can help to manage similar cases. This case was the first unusual presentation of its type. Keywords: Saccular Aneurysm, Aortic Dissection, Pseudoaneurysm, Aneurysm.