Duodenal diverticulum is an outpouching of the duodenal wall, generally of acquired (false) type representing herniation of mucosal and submucosal layers. Most commonly located in the second part of the duodenum (periampullary region — near the papilla of Vater). Incidence increases with age and has been reported in 5-22% of autopsy series. The vast majority are asymptomatic and incidentally detected. Complications are rare but can be serious: diverticulitis, hemorrhage, perforation, biliopancreatic duct obstruction (Lemmel syndrome), foreign body retention, and bacterial overgrowth. On CT, appears as a thin-walled structure containing air and/or fluid adjacent to the duodenum. Periampullary diverticula may facilitate gallstone formation. Treatment is generally not needed; surgical or endoscopic intervention is applied for complications.
Age Range
40-85
Peak Age
60
Gender
Equal
Prevalence
Common
Acquired duodenal diverticula form through herniation of mucosa and submucosa through natural weak points in the bowel wall (vascular penetration sites — mesoduodenal border). Increased intraluminal pressure (pulsion diverticula) triggers herniation. The periampullary region is particularly vulnerable because the bile duct and pancreatic duct weaken wall integrity. When diverticula become complicated, several mechanisms come into play: (1) Stasis and food accumulation → bacterial proliferation → diverticulitis → inflammation and wall thickening, (2) Periampullary diverticulum papilla displacement → bile flow disruption → cholestasis → Lemmel syndrome, (3) Vascular erosion → massive duodenal hemorrhage. On CT, uncomplicated diverticulum shows thin wall with low-density content (air, fluid), while diverticulitis adds wall thickening and perienteric inflammation.
Stoneless obstructive jaundice resulting from mechanical compression of the papilla of Vater by the periampullary diverticulum — Lemmel syndrome. Recognized by the triad of biliary dilation + periampullary diverticulum + absence of choledochal stones.
Thin-walled (<3 mm), well-defined structure containing air and/or fluid adjacent to the 2nd part of the duodenum (periampullary region) on portal venous phase. With oral contrast administration, the diverticulum lumen opacifies confirming connection with duodenum. Size is generally 1-4 cm though larger diverticula have been reported. No surrounding fat stranding in uncomplicated diverticulum.
Report Sentence
Thin-walled structure containing air/fluid adjacent to the 2nd part of duodenum is observed, consistent with duodenal diverticulum.
Periampullary diverticulum + intra/extrahepatic biliary dilation — without choledocholithiasis. The diverticulum displaces or compresses the papilla of Vater creating mechanical obstruction. CBD diameter >7 mm with possible gallbladder distension. Pancreatic duct dilation may also accompany.
Report Sentence
Biliary dilation accompanied by periampullary diverticulum is observed, consistent with Lemmel syndrome.
Wall thickening (>3 mm), perienteric fat stranding, surrounding fluid and/or gas collection in complicated diverticulitis. Wall enhancement is increased with prominent perienteric inflammation. In advanced cases, perforation → retroperitoneal or intraperitoneal free air + fluid. Diverticulitis findings may mimic acute pancreatitis.
Report Sentence
Wall thickening and perienteric inflammation findings in the duodenal diverticulum are observed, consistent with duodenal diverticulitis.
T2 hyperintense (fluid signal), well-defined, thin-walled structure adjacent to the duodenum on T2-weighted MR images. On MRCP sequences, diverticulum fluid content shows very bright signal and relationship with CBD/pancreatic duct is clearly visualized. MRI is superior to CT in evaluating relationship of periampullary diverticula with the papilla and biliary compression.
Report Sentence
T2 hyperintense diverticulum structure adjacent to the duodenum on MRI is observed, with its relationship to the biliary tract evaluated on MRCP.
Rare intraluminal (windsock) diverticulum — structure bounded by thin membrane within the duodenal lumen. 'Lumen within lumen' appearance on non-contrast CT. Different opacification timing on both sides of the membrane with oral contrast. Obstruction findings may accompany.
Report Sentence
Intraluminal diverticulum (windsock type) in the duodenal lumen is observed, consistent with incomplete congenital duodenal web.
Cystic/semisolid structure adjacent to the pancreatic head on B-mode ultrasound — diverticulum fluid content appears anechoic or low echogenicity. Food residue or gas bubbles may create echogenic foci. Periampullary diverticulum may be confused with pancreatic cyst or choledochal cyst on US — real-time evaluation with peristaltic movement and positional change provides distinguishing clue.
Report Sentence
Cystic structure adjacent to the pancreatic head is observed, duodenal diverticulum is considered; confirmation with CT or MRI is recommended.
Criteria
Acquired, false diverticulum — mucosal and submucosal herniation, most common type
Distinct Features
Most common in periampullary region. Generally asymptomatic. Incidence increases with age. Lumen connection demonstrated with oral contrast.
Criteria
Congenital, incomplete form of duodenal web — membrane extending within the lumen
Distinct Features
Very rare. Obstruction symptoms common. 'Lumen within lumen' appearance pathognomonic. May require surgical correction.
Criteria
Location adjacent to papilla of Vater (<2 cm) — high risk of biliopancreatic complications
Distinct Features
Highest risk for Lemmel syndrome. May create technical difficulty for ERCP. Association with recurrent pancreatitis reported.
Distinguishing Feature
In adhesive obstruction, transition point and proximal dilation; in diverticulum, localized structure and lumen connection
Distinguishing Feature
In Crohn's, skip lesions, mural stratification and fistulae; in diverticulum, isolated outpouching and thin wall
Distinguishing Feature
In TB, cecal contraction, asymmetric thickening and rim-enhancing lymphadenopathy; in diverticulum, thin-walled outpouching
Distinguishing Feature
Meckel's is in the ileum (60-100 cm proximal to ileocecal valve) and is a true diverticulum; duodenal diverticulum is in the duodenum and is a false diverticulum
Urgency
routineManagement
conservativeBiopsy
Not NeededFollow-up
no-follow-upUncomplicated duodenal diverticula do not require treatment or follow-up. In Lemmel syndrome, ERCP with papilla evaluation and sphincterotomy if needed. In diverticulitis, conservative treatment (antibiotics, bowel rest) is generally sufficient. Perforation requires emergency surgery. In hemorrhage, endoscopic hemostasis may be attempted; if unsuccessful, angiographic embolization or surgical intervention. Periampullary diverticula may complicate papilla localization during ERCP — need for experienced endoscopist and increased complication risk.
Duodenal diverticulum is usually asymptomatic and requires no treatment. Diverticulitis, bleeding, or Lemmel syndrome (biliary obstruction) are rare complications. Periampullary diverticula may complicate ERCP procedures.