Zollinger‑Ellison Syndrome (Gastrinoma) – Familial

Overview

Zollinger‑Ellison syndrome (ZES) is a rare disorder in which one or more tumors called gastrinomas produce excessive amounts of the hormone gastrin. The high gastrin levels stimulate the stomach lining to secrete large volumes of gastric acid, leading to severe peptic ulcer disease, gastro‑esophageal reflux, and diarrhea.

When ZES runs in families, it is usually part of a hereditary condition called multiple endocrine neoplasia type 1 (MEN‑1). MEN‑1 is an autosomal‑dominant syndrome that also predisposes affected individuals to tumors of the parathyroid glands, pituitary gland, and other neuroendocrine tissues.

Who it affects

• Both men and women; slight male predominance (≈55%).
• Typical age at diagnosis: 30–50 years for sporadic cases, but familial MEN‑1‑associated gastrinomas often present earlier, sometimes in the teens.

Prevalence

• Overall ZES: ~1–3 cases per million population (CDC, 2023).
• MEN‑1 occurs in ~1–10 per 100,000 people; ~20–30 % of MEN‑1 patients develop gastrinomas, making familial ZES an exceptionally rare subset (<0.1 per million).^{[1] NIH Genetic and Rare Diseases Information Center}

Symptoms

Symptoms arise from acid hypersecretion and from the tumor itself. The clinical picture can vary, especially in familial cases where tumors tend to be multifocal and smaller.

Gastro‑intestinal manifestations

• Recurrent or persistent peptic ulcers – often multiple, located beyond the duodenal bulb (jejunum, ileum) and resistant to standard therapy.
• Abdominal pain – cramping, usually post‑prandial due to ulcer irritation.
• Diarrhea – watery, sometimes steatorrhea; caused by acid inactivation of pancreatic enzymes and bile salts.
• Gastro‑esophageal reflux disease (GERD) – heartburn, regurgitation, esophagitis.
• Nausea & vomiting – especially after large meals.

Systemic signs

• Weight loss – due to malabsorption and chronic diarrhea.
• Fatigue – secondary to anemia from chronic GI bleeding.
• Osteopenia/Osteoporosis – long‑term acid excess may impair calcium absorption.

Signs related to MEN‑1 (when present)

• Hyperparathyroidism – hypercalcemia, kidney stones.
• Pituitary tumors – headaches, visual field defects, galactorrhea.
• Other neuroendocrine tumors – e.g., bronchial or pancreatic NETs.

Causes and Risk Factors

ZES is caused by gastrin‑producing neuroendocrine tumors. In the familial form, a germline mutation in the MEN1 gene on chromosome 11q13 leads to loss of the tumor suppressor protein menin.

Genetic basis

• MEN1 mutation – autosomal‑dominant inheritance; each child of an affected parent has a 50 % chance of inheriting the mutation.
• Over 1,300 different MEN1 pathogenic variants have been identified, most resulting in truncated or non‑functional menin.^{[2] WHO Classification of Tumours of Endocrine Organs}

Other risk factors

• Family history of MEN‑1 or ZES.
• Previous history of pancreatic or duodenal neuroendocrine tumors.
• Radiation exposure to the upper abdomen (very weak evidence).

Diagnosis

Diagnosing familial ZES requires a combination of biochemical testing, imaging, and genetic evaluation.

Biochemical confirmation

• Fasting serum gastrin – levels >1000 pg/mL (normal <100 pg/mL) are highly suggestive; intermediate elevations need stimulation testing.
• Secretin stimulation test – paradoxical rise in gastrin ≥120 pg/mL after IV secretin is diagnostic (sensitivity ≈ 90 %).
• Elevated gastric acid output measured by pentagastrin‑stimulated basal acid output (>15 mEq/hour).

Imaging studies

• Endoscopic ultrasound (EUS) – high resolution for small (<1 cm) duodenal or pancreatic gastrinomas.
• Multiphasic contrast CT or MRI – assesses size, location, and metastatic spread.
• Somatostatin receptor scintigraphy (Octreoscan) or Ga‑68 DOTATATE PET/CT – detects somatostatin‑receptor‑positive lesions; preferred for occult disease.

Genetic testing

• Sequencing of the MEN1 gene in the patient; if positive, cascade testing of first‑degree relatives.
• Genetic counseling is recommended before and after testing.

Differential diagnosis

Conditions that can mimic ZES include chronic H. pylori infection, NSAID‑induced ulcers, and other neuroendocrine tumors (e.g., VIPoma). Excluding these is essential.

Treatment Options

Management focuses on controlling acid hypersecretion, removing or controlling the tumor, and monitoring for MEN‑1–related neoplasms.

Acid‑suppressive therapy

• High‑dose proton pump inhibitors (PPIs) – omeprazole 40–80 mg daily or equivalent; most patients achieve symptom control.
• H2‑receptor antagonists – used as adjuncts or in PPI‑intolerant patients.
• Regular monitoring of gastric pH (target <3) and serum gastrin levels to avoid over‑suppression.

Surgical management

• Enucleation or duodenectomy for solitary, resectable gastrinomas (<2 cm).
• Pancreaticoduodenectomy (Whipple procedure) – considered for larger or multiple tumors when complete resection is feasible.
• In MEN‑1 patients, surgery is controversial because of multifocal disease; many experts favor medical control and surveillance unless tumors are >2–3 cm or show rapid growth.

Medical therapies for unresectable or metastatic disease

• Somatostatin analogues (octreotide, lanreotide) – control hormone secretion and may shrink tumors.
• Targeted therapy – everolimus (mTOR inhibitor) and sunitinib (tyrosine‑kinase inhibitor) have FDA approval for advanced pancreatic neuroendocrine tumors.
• Peptide receptor radionuclide therapy (PRRT) – ^177Lu‑DOTATATE for somatostatin‑receptor‑positive metastatic disease.
• Chemotherapy – reserved for high‑grade neuroendocrine carcinomas; regimens include streptozocin‑based or temozolomide‑capecitabine.

Lifestyle and supportive measures

• Avoid NSAIDs, aspirin, and alcohol, which aggravate ulcer formation.
• Small, frequent meals to reduce acid load.
• Supplement calcium and vitamin D if chronic hypocalcemia or bone loss is present.
• Vaccinations for patients on long‑term PPIs (e.g., CDC recommendations for pneumococcal and C. difficile prophylaxis).

Living with Zollinger‑Ellison Syndrome (Gastrinoma) – Familial

Adapting to a chronic condition involves practical day‑to‑day strategies.

Medication adherence

• Take PPIs exactly as prescribed; missing doses can precipitate ulcer bleeding.
• Keep a medication diary or use smartphone reminders.

Nutrition

• Low‑acid diet: limit citrus, tomato products, coffee, and spicy foods.
• High‑protein, low‑fat meals support healing and reduce gastric emptying time.
• Consider a dietitian experienced with gastrointestinal disorders.

Monitoring

• Annual upper endoscopy to assess ulcer healing and screen for new lesions.
• Serum gastrin and calcium levels every 6–12 months.
• Imaging (EUS or Ga‑68 DOTATATE PET) every 1–2 years, or sooner if symptoms change.
• Family screening: if a MEN1 mutation is identified, test relatives promptly.

Psychosocial health

• Join patient support groups (e.g., MEN‑1 Foundation).
• Address anxiety or depression with counseling; chronic disease can impact mental health.

Work and travel

• Carry a copy of your diagnosis, medication list, and emergency contact.
• Ask your physician for a “medical alert” card if high‑dose PPIs are essential.

Prevention

Because familial ZES is genetically determined, primary prevention is not possible. however, secondary prevention measures can limit disease impact.

• Genetic counseling for at‑risk families; consider pre‑implantation genetic diagnosis (PGD) if desired.
• Early detection through regular screening of mutation carriers reduces tumor burden.
• Eliminate modifiable ulcer‑risk factors: stop smoking, limit alcohol, avoid chronic NSAID use.

Complications

If untreated or inadequately controlled, ZES can lead to serious health problems.

• Perforated peptic ulcer – causing acute abdominal pain and peritonitis.
• Upper gastrointestinal bleeding – melena, hematemesis; may require endoscopic hemostasis or surgery.
• Gastric outlet obstruction due to edema or ulcer scarring.
• Malabsorption & nutritional deficiencies – fat‑soluble vitamin deficits, anemia.
• Metastatic disease – liver or lymph node involvement in ~30 % of gastrinomas.
• Bone disease – secondary hyperparathyroidism from MEN‑1 can cause osteoporosis.
• Psychological burden – chronic pain and medication side‑effects may affect quality of life.

When to Seek Emergency Care

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References

1. National Institutes of Health, Genetic and Rare Diseases Information Center. “Zollinger‑Ellison Syndrome.” Updated 2023.
2. World Health Organization. “WHO Classification of Tumours of Endocrine Organs, 5th Edition.” 2022.
3. Mayo Clinic. “Zollinger‑Ellison syndrome.” Accessed May 2024.
4. Cleveland Clinic. “Multiple Endocrine Neoplasia Type 1 (MEN1).” 2023.
5. American College of Gastroenterology. “Guidelines for the Management of Peptic Ulcer Disease.” 2022.
6. U.S. Centers for Disease Control and Prevention. “Vaccines for Adults.” Updated 2024.