An 84-year-old man who resided in a nursing home presented to the emergency department with a 3-week history of gradually worsening nausea, anorexia, and postprandial left upper quadrant abdominal pain with eventual food avoidance and greater than 10% weight loss. He had no difficulty passing flatus or having bowel movements. His surgical history was significant for an infrarenal abdominal aortic aneurysm repair 12 years prior to presentation. There was no known history of peptic ulcer disease, biliary disease, or malignancy. Physical examination revealed a cachectic man with a height of 1.7 m and weight of 45 kg. He was afebrile with a blood pressure of 130/70 mm Hg, pulse of 85 beats/min, respiratory rate of 22/min, and a 95% arterial oxygen saturation (SaO2) on room air. His abdomen was soft and nondistended with moderate left upper quadrant tenderness but no peritoneal signs. A midline surgical scar was well healed; no external hernias were evident. Rectal examination revealed no masses or occult fecal blood. Laboratory data and chest radiograph findings were unremarkable. A computed tomographic scan of the abdomen revealed a markedly distended stomach and dilated proximal duodenum with distal decompression. Esophagogastroduodenoscopy was performed, which revealed a narrowing of the distal portion of the duodenum with a grossly dilated stomach and proximal duodenum. There was no evidence of an intraluminal mass. An upper gastrointestinal tract barium study showed normal motility with failure of the fourth portion of the duodenum to completely opacify (Figure).