Median arcuate ligament syndrome presenting as acute mesenteric hemorrhage: A case report

Median arcuate ligament syndrome (MALS) is a relatively common, yet under-recognized condition caused by external compression of the celiac artery by the median arcuate ligament. Although often asymptomatic, MALS may present with chronic gastrointestinal symptoms, and rarely, with acute complications due to collateral vessel rupture. We present the case of a 59-year-old woman who arrived at a rural emergency department with acute left flank pain and emesis, ultimately diagnosed with intra-abdominal hemorrhage from a ruptured pseudoaneurysm. In chronic celiac artery stenosis, collateral pathways, particularly the Arc of Bühler and the pancreaticoduodenal arcade can become hypertrophied and predisposed to pseudoaneurysm formation. Rupture of these pseudoaneurysms may mimic other causes of acute mesenteric bleeding, such as hemorrhagic pancreatitis, and carry high mortality if not promptly identified. This case underscores the importance of recognizing splanchnic arterial collaterals as potential sources of hemorrhage in MALS and highlights the need for early imaging, especially in resource-limited settings. Prompt angiographic assessment and embolization can be lifesaving.