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Duodenal diverticulum is an outpouching of the duodenal wall, most commonly in the second portion (near the ampulla of Vater).

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It may be congenital (true diverticulum) involving all layers or more commonly acquired (false diverticulum) involving only mucosa and submucosa herniating through the muscular wall.
They are usually extramural and broad-based.

Etiopathology

Congenital: Developmental weakness in duodenal wall.
Acquired: Increased intraluminal pressure and peristaltic stress leading to mucosal herniation through weak points (e.g., near vascular entry sites).
Commonly associated with periampullary region (juxtapapillary diverticulum).

Clinical Features

Prevalence: 5–20% on imaging/autopsy; more common in elderly.:
Usually asymptomatic (incidental finding).
If symptomatic: postprandial discomfort, bloating, or vague abdominal pain.

Radiology

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Radiologically: outpouching with air/contrast-fluid level is diagnostic.

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Duodenal diverticulum is a common, usually incidental finding near the ampulla.

Modality	Imaging features
Barium studies	• Outpouching from duodenal lumen, usually rounded, with contrast filling.
• May show food/debris within.
• If periampullary, may mimic choledochal cyst or pseudocyst.
CT	• Thin-walled, sac-like structure adjacent to duodenum, often with air-fluid or contrast-fluid level.
• Periampullary diverticulum may mimic pancreatic or choledochal cyst but presence of air or enteric contrast confirms diverticulum.
• Complicated diverticulitis: wall thickening, fat stranding, possible perforation.
MR	May show periampullary cystic lesion; recognition of luminal communication avoids misdiagnosis as cystic neoplasm or choledochal cyst.

![Different imaging of intraduodenal diverticula on barium upper gastrointestinal series. A extraluminal duodenum diverticulum. B Intraluminal duodenum diverticulum distended by contrast agent with the typical windsock appearance. C IDD in the second–third part of the duodenum surrounded by a thin radiolucent wall. D IDD distended by barium. E IDD partially distended by gas in the upper part and barium in the lower part. F IDD surrounded by a radiolucent wall

Whittle, C., Maldonado, I., Campos, O. et al. Imaging of intraluminal duodenal diverticulum in adults, an infrequent entity: pictorial essay. Egypt J Radiol Nucl Med 55, 227 (2024). https://doi.org/10.1186/s43055-024-01387-9](attachment:d817bbb6-53fc-453b-9937-e94b84b7913e:43055_2024_1387_Fig3_HTML.webp)

Different imaging of intraduodenal diverticula on barium upper gastrointestinal series. A extraluminal duodenum diverticulum. B Intraluminal duodenum diverticulum distended by contrast agent with the typical windsock appearance. C IDD in the second–third part of the duodenum surrounded by a thin radiolucent wall. D IDD distended by barium. E IDD partially distended by gas in the upper part and barium in the lower part. F IDD surrounded by a radiolucent wall

![52-year-old woman with a duodenal diverticulum. a CECT in the portal venous phase shows a 1.5 × 0.8 cm cystic lesion with focus of air in the pancreatic neck/body (arrow). b On MRI, the lesion is T2 hyperintense with T2 with susceptibility artifact in the non-dependent portion, indicating gas (arrow). These findings are consistent with a duodenal diverticulum

Yasrab, M., Kwak, S.J., Khoshpouri, P. et al. Misdiagnosis of pancreatic intraductal papillary mucinous neoplasms and the challenge of mimicking lesions: imaging diagnosis and differentiation strategies. Abdom Radiol 50, 2241–2257 (2025). https://doi.org/10.1007/s00261-024-04551-x](attachment:e4a69f44-e077-44e8-b6bc-4d369af5aa0a:261_2024_4551_Fig10_HTML.webp)

52-year-old woman with a duodenal diverticulum. a CECT in the portal venous phase shows a 1.5 × 0.8 cm cystic lesion with focus of air in the pancreatic neck/body (arrow). b On MRI, the lesion is T2 hyperintense with T2 with susceptibility artifact in the non-dependent portion, indicating gas (arrow). These findings are consistent with a duodenal diverticulum