What is the recommended management approach for a patient diagnosed with a duplication cyst of the duodenum?

Management of Duodenal Duplication Cysts

Asymptomatic duodenal duplication cysts do not require surveillance or intervention, while symptomatic lesions should be treated with surgical removal when feasible. 1

Diagnostic Approach

Endoscopic ultrasound (EUS) is the diagnostic gold standard, revealing an anechoic, smooth, spherical or tubular structure with a well-defined wall that does not communicate with the gastrointestinal lumen. 1, 2 The characteristic endosonographic appearance typically eliminates the need for tissue sampling. 1

Key Diagnostic Considerations:

• Avoid EUS-FNA for mediastinal foregut duplication cysts due to risk of mediastinitis, though sampling may be necessary for duodenal cysts adjacent to the pancreas to exclude pancreatic pseudocyst or pancreatic cystic neoplasm. 1, 2

• Cross-sectional imaging with CT or MRI should be obtained to delineate anatomical relationships, particularly proximity to the ampulla, common bile duct, and pancreatic duct. 3

• 3D reconstruction of imaging can be invaluable for surgical planning, specifically to identify any communication with the biliopancreatic ducts (present in approximately 29% of cases). 3

Treatment Algorithm

For Asymptomatic Cysts:

No intervention or surveillance is required. 1 These lesions are typically benign and remain stable over time, though they carry a theoretical risk of complications including enlargement, mass effect, rupture, bleeding, or rare malignant transformation. 1, 2, 3

For Symptomatic Cysts:

Symptoms warranting intervention include recurrent pancreatitis, abdominal pain, jaundice, bleeding, or gastric outlet obstruction. 4, 3, 5

Treatment options in order of preference:

1. Endoscopic marsupialization (first-line for intraluminal cysts):

   • Perform endoscopic incision and marsupialization using needle-knife sphincterotome, cystotome, or polypectomy snare. 4
   • This approach achieves excellent long-term results with median follow-up showing sustained symptom resolution at 7+ years. 4
   • Major advantage: Minimally invasive with no major complications reported in case series. 4

2. Complete surgical excision (preferred when endoscopic approach fails or is not feasible):

   • Indicated for cysts with potential malignancy risk (three cases of malignant transformation have been reported). 3
   • Enucleation or partial resection with marsupialization is the surgical approach of choice for cysts without biliopancreatic communication. 3, 6, 7
   • Preserves duodenal integrity while achieving complete removal. 3

3. Pancreaticoduodenectomy (last resort only):

   • Reserved exclusively for cases where the cyst cannot be separated from the ampulla or biliopancreatic structures. 3
   • This major procedure should be avoided whenever possible due to high morbidity, mortality, and poor quality of life. 3

Critical Pitfalls to Avoid

• Do not confuse duodenal duplication cysts with choledochoceles (Todani type III), as this leads to inappropriate surgical planning. 3, 7 Ultrasound characteristics and lack of communication with the biliary tree distinguish duplication cysts. 7

• Do not perform routine surveillance after complete surgical resection of benign duplication cysts, as they have excellent prognosis when fully excised. 2

• Do not assume all cysts are benign—while rare, malignant transformation has been documented, making complete excision preferable to partial treatments in surgical candidates. 3

Special Considerations

Location matters for surgical approach: Cysts in the second portion of the duodenum near the ampulla require meticulous preoperative mapping with 3D reconstruction to avoid injury to the common bile duct during excision. 3 Intraoperative methylene blue injection through the cystic duct can help localize the ampulla. 3

Postoperative bleeding risk: Hemostasis at the duodenal mucosa resection site requires careful attention, as bleeding complications can occur in the early postoperative period. 3