The Twin Evils of Concomitant Rare Pathology with Variant Anatomy: Superior Mesenteric Artery Aneurysm and a Replaced Right Hepatic Artery.

Aneurysmal degeneration of the superior mesenteric artery (SMA) is a rare clinical finding, estimated to affect <1% of the general population in postmortem studies. Due to the rare prevalence of aneurysms affecting the SMA, there are no clear or definitive published consensus guidelines for its management at presentation, with both surgical and endovascular options described. An aberrant or replaced right hepatic artery (RRHA) is thought to affect 10-15% of the population. The prevalence of both conditions presenting concomitantly is unknown, but undoubtedly even rarer. We describe the successful management of a symptomatic SMA aneurysm with an RRHA emerging from the aneurysmal sac presenting to our vascular unit. This was repaired via an open surgical approach with SMA aneurysmectomy and interposition grafting using reversed vein with preservation of RHA liver perfusion via a novel reconstruction option. This case highlights the challenge that visceral aneurysms pose, especially when simple or orthodox reconstruction options are limited due to rare or unusual anatomy.