[Accessory retrograde aneurysmal aortic lumen supplying the inferior mesenteric artery]

We report the case of a patient with infrarenal abdominal aortic aneurysm with mural thrombus covering the ostium of a patent inferior mesenteric artery (IMA). The IMA was supplied via flow from an accessory aneurysmal lumen within the mural thrombus that filled retrogradely from the aorta. This unusual pattern, associated with calcifications within the thrombus, raised the possibility of chronic aortic dissection.