Differential Diagnosis for a 6 cm Diameter, Infrarenal Aortic Mass with a Periaortic Hematoma

• Single Most Likely Diagnosis
  • Aortic aneurysm with rupture or impending rupture: This is the most likely diagnosis given the size of the mass and the presence of a periaortic hematoma, which suggests leakage or impending rupture of the aneurysm.
• Other Likely Diagnoses
  • Aortitis (inflammatory aortic disease): Conditions like Takayasu arteritis or giant cell arteritis could cause an aortic mass and periaortic hematoma, although they are less common than aneurysms.
  • Aortic pseudoaneurysm: A false aneurysm could present similarly, especially if there's a history of trauma or previous aortic surgery.
  • Aortic thrombus or mural thrombus: Although less likely to cause a significant periaortic hematoma, a large thrombus could potentially lead to such a presentation, especially if there's associated aortic disease.
• Do Not Miss Diagnoses
  • Aortic dissection: This is a medical emergency that could present with a periaortic hematoma and might be suggested by the presence of an aortic mass, especially if there's a history of hypertension or aortic disease.
  • Ruptured aortic graft (if applicable): In patients with a history of aortic surgery, a ruptured graft could present similarly and is a critical diagnosis not to miss.
• Rare Diagnoses
  • Primary aortic tumors (e.g., leiomyosarcoma): These are exceedingly rare and could present as an aortic mass but are much less common than aneurysms or other vascular pathologies.
  • Infectious aortitis (mycotic aneurysm): This could present with an aortic mass and periaortic hematoma, especially in immunocompromised patients or those with a history of endocarditis.
  • Lymphoma or metastatic disease involving the aorta: Although rare, these conditions could potentially cause an aortic mass, but they would be less likely to cause a significant periaortic hematoma compared to vascular pathologies.