A 51-year-old woman with a history of hypertension and chronic constipation presented with abdominal pain of 2 weeks' duration. The pain was continuous, worsened with eating, was associated with nausea, and radiated to her back. She reported no vomiting, fever, diarrhea, or weight loss, and her vital signs were normal. Her abdomen was distended, diffusely tender on palpation, and tympanic on percussion on the upper half and dull on the lower half. Bowel sounds were missing on the left side, and a large mass was palpated in that area. Laboratory evaluation was unremarkable. Computed tomography (CT) showed massive dilatation of . . .