Can duodenal neuroendocrine tumors (NETs) present with upper gastrointestinal (UGI) bleed?

Duodenal Neuroendocrine Tumors and Upper Gastrointestinal Bleeding

Yes, duodenal neuroendocrine tumors (NETs) can present with upper gastrointestinal bleeding, although this is not their most common presentation. Duodenal NETs may cause bleeding due to local tumor growth and mucosal ulceration, which can range from occult bleeding to overt hemorrhage 1.

Epidemiology and Characteristics of Duodenal NETs

• Duodenal NETs represent approximately 3% of all gastrointestinal neuroendocrine tumors 2
• They have a relatively high rate of metastasis, with approximately 60% showing nodal metastases and 30% showing liver metastases at presentation 2
• About half of gastrinomas (a specific type of functional NET) arise in the duodenum 2

Clinical Presentations of Duodenal NETs

• Most gastroenteropancreatic NETs may present with non-specific symptoms including pain, nausea, vomiting, and in some cases, anemia due to intestinal blood loss 2
• Duodenal NETs can be asymptomatic in many cases, leading to delay in diagnosis 1
• When symptomatic, clinical manifestations are often related to:
  • Local tumor growth and mucosal ulceration 1
  • Hormonal syndromes (in functioning tumors) 2
  • Mass effect from the primary tumor or metastases 2

Upper GI Bleeding as a Presentation

• GI bleeding can be the initial presenting symptom of malignancy in up to 77% of patients with GI tumors that bleed 3
• Visible bleeding is present in approximately 33% of upper GI/small bowel tumors that cause bleeding 3
• The most common endoscopic finding in bleeding GI tumors is clean-based tumor ulceration 3
• Duodenal NETs can cause overt upper gastrointestinal bleeding and anemia, as documented in case reports 1
• Some duodenal NETs are discovered incidentally during endoscopic evaluation of iron-deficiency anemia 4

Diagnostic Approach for Suspected Duodenal NETs with Bleeding

• Upper endoscopy is the most appropriate initial diagnostic technique for investigation of upper GI bleeding 2
• Endoscopic ultrasound (EUS) may help in further characterizing the lesion and assessing depth of invasion 4
• Biopsy with immunohistochemical staining for chromogranin A and synaptophysin is essential for diagnosis 2
• Ki-67 (MIB-1) immunohistochemistry is mandatory to grade the tumor according to WHO classification 2

Management Considerations

• Initial endoscopic hemostasis is often successful for bleeding GI tumors, but rebleeding is common 3
• For localized duodenal NETs, endoscopic resection is recommended if feasible 2
• Other surgical options include transduodenal local excision with or without lymph node sampling and pancreatoduodenectomy 2
• The choice of procedure depends on tumor size, location, and presence of metastases:
  • For tumors ≤1.5 cm, local or endoscopic resection may be appropriate 5
  • For tumors >1.5 cm, more extensive surgery may be needed due to higher risk of lymph node metastasis 5
• Tumor biology (grade and presence of metastasis) rather than extent of resection dictates prognosis 5

Prognosis

• The overall prognosis for duodenal NETs is generally better than for other upper GI malignancies 3
• Factors associated with worse recurrence-free survival include:
  • Advanced tumor grade 5
  • Metastasis at diagnosis 5
  • Tumor size >1.5 cm (associated with higher risk of lymph node metastasis) 5

Important Considerations and Pitfalls

• Duodenal NETs may be difficult to identify on routine endoscopy due to their submucosal location and sometimes subtle appearance 4, 6
• Multiple endoscopic examinations may be required for diagnosis 4
• Even small duodenal NETs can cause significant bleeding requiring intervention 1
• Pancreaticoduodenectomy, while more extensive, is associated with longer hospital stays and higher risk of perioperative complications compared to local resection 5