Differential Diagnosis for Irregular Contour and Outpouching Distal Aortic Arch
- Single most likely diagnosis
- Penetrating atherosclerotic ulcer (PAU) with pseudoaneurysm: This is the most likely diagnosis given the description of an irregular contour and outpouching of the distal aortic arch, which is consistent with a penetrating ulcer that has led to the formation of a pseudoaneurysm. The increase in size of the pseudoaneurysm supports this diagnosis.
- Other Likely diagnoses
- Aortic dissection: Although less likely than PAU, an aortic dissection could present with an irregular contour of the aortic arch and could potentially lead to the formation of a pseudoaneurysm if there is a re-entry tear.
- Infectious aortitis: This condition, which involves infection of the aortic wall, could lead to weakening of the wall and formation of a pseudoaneurysm, although it is less common than PAU.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Aortic transection: Although rare, a traumatic injury to the aorta could result in an irregular contour and pseudoaneurysm formation. Missing this diagnosis could be catastrophic.
- Mycotic aneurysm: An aneurysm caused by an infectious process, which could present similarly to a PAU with pseudoaneurysm. It's crucial to consider this diagnosis due to its high mortality rate if left untreated.
- Rare diagnoses
- Vasculitis (e.g., Takayasu arteritis, giant cell arteritis): These inflammatory conditions affecting the blood vessels could potentially lead to weakening of the aortic wall and formation of aneurysms or pseudoaneurysms, although they are much less common than other diagnoses listed here.
- Congenital aortic anomalies: Certain congenital conditions could predispose to aneurysm or pseudoaneurysm formation, but these would be extremely rare in the context provided.