An 89-year-old man was referred to our surgical emergency department by his physician for acute abdominal pain that had lasted 8 hours with vomiting. He had hypertension but no history of previous abdominal surgery. At admission, his vital signs were normal, and no fever was noted. Neurological examination results were normal. Abdominal physical examination revealed diffuse abdominal pain—more acute in the epigastrium—without a palpable mass. Blood chemistry screening results showed a white blood cell count of 10.9/μL and a C-reactive protein level of 5 mg/L. (To convert the white blood cell count to cells ×109 per liter, multiply by 0.001; to convert the C-reactive protein level to nanomoles per liter, multiply by 9.524.) Liver and pancreatic function test results were normal. Contrast-enhanced computed tomography of the abdomen showed C-shaped bowel loops within the left upper quadrant associated with mesenteric infiltration, the absence of bowel wall enhancement, and a mesenteric whirl sign located anterior to the left lobe of the liver (Figure 1).