A 62-year-old woman had a 12-hour history of acute-onset epigastric and right upper quadrant pain with radiation to the back. She was febrile, had a diffusely tender abdomen with no peritoneal signs and a leukocytosis of 14.0 х 10⁹/L. An abdominal series did not show evidence of free air. CT of the abdomen revealed peripancreatic fat stranding and retroperitoneal gas bubbles at the third and fourth stages of the duodenum (Fig. 1). Ruptured diverticulum of the distal duodenum was diagnosed.

Duodenal diverticula are found in up to 22% of the population.¹ Of these, only 1%–2% of patients are symptomatic and require surgery. The rarest, most severe complication is perforation, which carries a death rate of up to 30%. Although the signs and symptoms of perforated duodenal diverticulitis are often nonspecific, and the radiologic findings subtle, a correct preoperative diagnosis is essential and may significantly lower this rate.² CT is the modality of choice. Findings consist of a thickened bowel wall, mesenteric fat stranding and an extraluminal collection of air or fluid, often retroperitoneal.³ In 60% of cases, a duodenal diverticulum is identified in the juxtapapillary position.