Congenital superior mesenteric artery aneurysm in a 6-week-old infant presenting with upper gastrointestinal bleeding

Abstract Visceral artery aneurysms are rare in infants and children. The majority of cases are caused by genetic syndromes, trauma, or infection. Although the majority of aneurysms are asymptomatic, visceral artery aneurysms can present with abdominal pain, nausea/vomiting, or rupture. Aneurysm rupture can manifest as hemodynamic instability and/or gastrointestinal bleeding. We present the case of a congenital idiopathic aneurysm of the superior mesenteric artery in a 6-week-old infant who presented with gastrointestinal bleeding. We report a stepwise surgical approach to achieving aneurysm exclusion and thrombosis, and highlight the robust mesenteric collateral circulation that can develop in pediatric patients.