Stomach: Gastrinoma (Zollinger-Ellison Syndrome)

Gastrinoma (Zollinger-Ellison Syndrome/ZES)

Basics

  • Gastrin Secreting Tumor
  • About Half Are Malignant (50-60%)
  • Gastrinoma (Passaro) Triangle – Contain 80% of Tumors
    • Junction of the Cystic & Common Bile Ducts
    • Junction of the Second & Third Portions of the Duodenum
    • Junction of the Neck & Body of the Pancreas
  • Most Common in Males

Presentation

  • Severe/Refractory Peptic Ulcers
  • Most Common Ulcer Location: Proximal Duodenum (Some in Distal & Jejunum)
  • Symptoms:
    • Pain
    • Diarrhea
    • GERD
    • Nausea & Vomiting

Gastrinoma Triangle 1

Diagnosis

  • Screening Tests (Non-Diagnostic):
    • Elevated Fasting Gastrin While Off PPI for 3-7 Days
    • Acid Present in Gastric pH Analysis
  • Diagnosis: Marked Gastrin Increase After Secretin Stimulation Test
    • Would Normally Show Minimal Change
    • Must Hold PPI Prior to Test
    • If Unsafe to Hold PPI (Life-Threatening Bleeding, etc.): Consider Somatostatin Receptor Imaging for Diagnosis & Localization
  • Localization:
    • Initial: CT or MRI
    • If Fails: Somatostatin Receptor Imaging
      • Somatostatin (Octreotide) Receptor Scintigraphy (SRS)
        • Classically Used
        • Most Sensitive Test
      • Functional PET Scans
        • Becoming More Prevalent with Higher Sensitivity
        • Radiotracer: Ga-68 DOTATATE or Ga-68 DOTATOC
    • If Imaging Fails: EUS
    • If EUS Fails: Selective Arterial Stimulation with Hepatic Venous Sampling
    • If High Suspicion but Still Unable to Localize: Surgical Exploration

Treatment

  • Resectable:
    • < 2-3 cm: Enucleate
    • > 2-3 cm, Local Invasion or N/M+: Resection
      • Pancreatic Head/Neck: Pancreaticoduodenectomy
      • Pancreatic Body/Tail: Distal Pancreatectomy
        • If Malignancy Suspected: Concurrent Splenectomy
      • Entire Pancreas: Total Pancreatectomy
  • Unresectable or Mets:
    • Resect Mets if Able
    • Symptomatic Tx: PPI
      • If Fails: Octreotide
    • If Severe/Enlarging: Chemotherapy
      • Classic Regimen: Streptozocin with/without Doxorubicin (Toxic to Beta Cells)
      • Newer Regimen: Temozolomide with/without Capecitabine (CAPTEM)

PNET on CT 2

PNET on EUS 2

PNET on SRS 2

PNET on Functional PET 2

References

  1. Blaus B. Wikimedia Commons (License: CC BY-SA-4.0) – Altered
  2. Kartalis N, Mucelli RM, Sundin A. Recent developments in imaging of pancreatic neuroendocrine tumors. Ann Gastroenterol. 2015 Apr-Jun;28(2):193-202. (License: CC BY-NC-SA-3.0)