Soft tissue case 61.

A 55-year-old man presented to the emergency department with a 12-hour history of severe crampy abdominal pain, nausea, vomiting and obstipation. The patient had a complex medical history, including coronary artery disease, lupus, hypothyroidism, epilepsy, pancreatitis and renal calculi. However, the patient had no history of a hernia or abdominal surgery. Physical examination revealed a temperature of 38.5 degrees C and a soft distended abdomen that was diffusely tender without signs of peritonitis. The rest of the physical examination was unremarkable. Routine laboratory investigations including a complete blood cell count, electrolytes, liver enzymes and amylase were normal, with the exception of a decreased hemoglobin level of 116 g/L. We ordered a plain abdominal radiograph (Fig. 1) and a contrast-enhanced computed tomography (CT) scan of his abdomen. What is your diagnosis?