Case Report: Delayed intra-abdominal hemorrhage in a patient with a duodenal stump tumor after Billroth II gastrectomy.

Findings: A 77-year-old female with a 3-month history of dizziness and fatigue was diagnosed with massive gastrointestinal hemorrhage and duodenal stump adenocarcinoma via multimodal evaluation. She underwent duodenal stump tumor resection. On postoperative day 11, she developed delayed intra-abdominal hemorrhage from a artery pseudoaneurysm. Abdominal CTA detected a pseudoaneurysm in a superior mesenteric artery branch with contrast extravasation; emergency DSA-guided embolization successfully stopped bleeding. However, on postoperative day 25, she developed severe rectal bleeding; colonoscopy showed extensive ischemic necrosis in the descending colon. Despite supportive care, the patient's family discontinued treatment due to persistent bleeding and septic shock, and she died 1 week after discharge. Interpretation: Duodenal stump tumors require a high index of suspicion for diagnosis, as their nonspecific symptoms are often misattributed to postsurgical sequelae. Multimodal imaging and gastroscopy with biopsy are critical for preoperative planning. Delayed postoperative pseudoaneurysm-related hemorrhage is extremely rare but life-threatening; CTA and DSA are essential for rapid diagnosis and intervention. While DSA-guided embolization effectively controls bleeding, it carries a risk of bowel ischemia that requires close monitoring. This case underscores the need for meticulous preoperative assessment, careful surgical technique to avoid vascular injury, and postoperative vigilance for rare complications-supporting the utility of integrated clinical-radiological management in complex cases.