An Unusual Cause of Gastric Outlet Obstruction: A Visceral Artery Pseudoaneurysm Presenting a Diagnostic Pitfall

Visceral artery pseudoaneurysms are rare but potentially life-threatening lesions, and their presentation as a bowel obstruction syndrome is exceptional.We report the case of a 68-year-old man with atrial fibrillation treated with apixaban who was admitted with acute abdominal pain, progressive abdominal distension, and bilious vomiting.Contrast-enhanced computed tomography (CT) revealed gastric and proximal duodenal dilatation associated with a large retroperitoneal hematoma compressing the duodenum and a vascular lesion arising from the superior mesenteric artery (SMA) territory.Angiography confirmed a pseudoaneurysm arising from a proximal branch of the SMA at the level of the pancreaticoduodenal arcade, which was treated by selective embolization.Despite initial angiographic control, subsequent hemodynamic and abdominal deterioration required emergency laparotomy, which revealed hemoperitoneum and active bleeding in the pancreaticoduodenal region.Surgical hemostasis was achieved without bowel resection, followed by a favorable postoperative course.This case highlights that a visceral artery pseudoaneurysm may exceptionally mimic bowel obstruction through duodenal compression caused by a retroperitoneal hematoma.Early contrast-enhanced imaging and multidisciplinary management involving interventional radiology and surgery are essential.