Hemodynamic Insights Into an Accessory Splenic Artery Aneurysm Arising From the Superior Mesenteric Artery.

BACKGROUND: Splenic artery variations involve anomalies in origin, course, and branching. Notably, the accessory splenic artery (ASA) is a rare independent, ectopic aberrant duplication outside the celiac trunk, making its comprehension crucial for safety during endovascular interventions. CASE SUMMARY: This case report describes a 34-year-old woman with a rare splenic artery duplication, consisting of a primary splenic artery normally originating from the celiac trunk and an ASA arising from the superior mesenteric artery that harbored a distal saccular aneurysm. DISCUSSION: An ASA originating from the superior mesenteric artery and associated with aneurysm formation is an extremely rare anatomical variation. Hemodynamic evaluations based on computational fluid dynamics simulation indicated that the unique vascular configuration of this aberrant artery may predispose the aneurysm to an elevated risk of rupture. TAKE-HOME MESSAGE: This type of accessory splenic artery originating from the superior mesenteric artery is reported here for the first time.