A 57-year-old woman was admitted to the hospital with melena and dyspnea. Her initial hemoglobin level was 6.5 g/dL. She had a history of acute pancreatitis with splenic pseudoaneurysm, which had been treated with angiographic coil embolization 1 year previously. After transfusion of several packs of red blood cells and tests for anemia, she underwent endoscopic examination. The colonoscopy findings were normal. Gastroscopic examination revealed blood in the second and third portions of the duodenum and suspicious active bleeding from the orifice of the ampulla of Vater (Fig. 1A-C). Because the bleeding focus was not clear, computer tomography (CT) scans and capsule endoscopy were performed. There was no evidence of bleeding in the small bowel during capsule endoscopy; however, CT scans revealed parenchymal swelling and an early enhancing lesion in the pancreatic uncinate process (Fig. 1D, E). What is the most likely diagnosis?