Zollinger‑Ellison Syndrome (Benign) – A Patient‑Friendly Guide

Overview

Zollinger‑Ellison syndrome (ZES) is a rare disorder in which one or more tumors, called gastrin‑producing neuroendocrine tumors (gastrinomas), develop in the pancreas or duodenum. These tumors secrete excessive amounts of gastrin, a hormone that stimulates the stomach to produce large volumes of acid. The resulting hyperacidity leads to severe peptic ulcer disease, gastro‑esophageal reflux, and a range of digestive symptoms.

Key points

• Benign vs. malignant: Most gastrinomas are benign, but about 20‑30 % can become malignant or metastasize, most often to the liver or lymph nodes.
• Who it affects: Adults aged 30‑60 years are most commonly diagnosed. Both men and women are affected equally.
• Prevalence: ZES occurs in roughly 1–3 per million people worldwide. Approximately 10 % of cases are associated with the inherited condition multiple endocrine neoplasia type 1 (MEN‑1).

Symptoms

Because excess gastric acid damages the lining of the stomach and duodenum, symptoms can be severe and may develop quickly. The most common manifestations include:

Gastro‑intestinal symptoms

• Recurrent abdominal pain: Often epigastric, worse after meals.
• Severe, refractory peptic ulcers: Ulcers may be multiple, large, and located beyond the duodenal bulb (e.g., jejunal ulcers).
• Diarrhea: Occurs in 40‑60 % of patients; can be watery or fatty (steatorrhea) due to acid inactivation of pancreatic enzymes.
• Nausea & vomiting: May be triggered by ulcer pain or gastrin-induced gastric emptying delay.
• Gastro‑esophageal reflux disease (GERD): Acid overload can aggravate heartburn and esophagitis.

Systemic symptoms

• Weight loss: From malabsorption and reduced intake.
• Fatigue: Chronic anemia from occult bleeding or malnutrition.
• Hypercalcemia: Particularly when ZES is part of MEN‑1.
• Skin flushing or itching: Rare, but may occur with hormone‑secreting tumors.

Causes and Risk Factors

Primary cause

ZES is caused by gastrin‑secreting neuroendocrine tumors (gastrinomas). Most are sporadic, arising without a clear genetic trigger. However, about 10 % are linked to multiple endocrine neoplasia type 1 (MEN‑1), an inherited mutation in the MEN1 tumor suppressor gene.

Risk factors

• Family history of MEN‑1: Inherited autosomal‑dominant pattern.
• Age: Peak incidence between 30‑60 years.
• Chronic H. pylori infection: While not a direct cause, it can exacerbate ulcer disease and mask ZES.
• Smoking: Increases risk of neuroendocrine tumor development.
• Radiation exposure: Occupational or therapeutic radiation may elevate risk, though evidence is limited.

Diagnosis

Because symptoms overlap with common peptic ulcer disease, a high index of suspicion is essential, especially when ulcers are refractory to standard therapy.

Initial work‑up

• Fasting serum gastrin level: Levels >1000 pg/mL (normal < 100 pg/mL) in the presence of low gastric pH is diagnostic. Note: Proton‑pump inhibitors (PPIs) elevate gastrin; the test is usually performed after stopping PPIs for 7‑10 days, if safe.
• Secretin stimulation test: Administration of secretin paradoxically raises gastrin >120 pg/mL in ZES patients, useful when basal gastrin is equivocal.
• Gastric pH measurement: A pH < 2 supports hyperacidic state.

Imaging to locate the tumor

• Endoscopic ultrasound (EUS): Highly sensitive for small pancreatic or duodenal lesions.
• Somatostatin receptor scintigraphy (Octreoscan) or 68Ga‑DOTATATE PET/CT: Detects gastrinomas that express somatostatin receptors.
• CT or MRI abdomen: Evaluate size, local invasion, and metastasis.
• Selective arterial secretin stimulation test (SASS): Rarely used; measures gastrin gradients from different arterial territories.

Pathology

If surgical removal is performed, the specimen is examined histologically. Benign gastrinomas show well‑differentiated neuroendocrine features, low mitotic index, and Ki‑67 < 3 %.

Treatment Options

Treatment aims to control acid hypersecretion, remove or shrink the tumor, and monitor for recurrence.

Medical management

• High‑dose proton‑pump inhibitors (PPIs): Omeprazole 60 mg daily or equivalent is first‑line. PPIs are the most effective way to neutralize acid and heal ulcers.
• Histamine‑2 receptor antagonists (H2 blockers): Cimetidine or ranitidine can be added but are less effective than PPIs.
• Octreotide or Lanreotide (somatostatin analogues): Reduce gastrin secretion and may stabilize tumor growth, especially in metastatic disease.
• Chemotherapy & targeted therapy: For malignant or unresectable disease, agents such as streptozocin, temozolomide, or everolimus are used under oncologist supervision.

Surgical options

• Enucleation: Removal of a solitary, small gastrinoma while preserving pancreatic tissue.
• Pancreaticoduodenectomy (Whipple procedure): Indicated for larger duodenal tumors or those involving the pancreatic head.
• Distal pancreatectomy: For tumors located in the pancreatic tail.
• Debulking surgery: In metastatic cases, removal of as much tumor bulk as possible to improve symptom control.

Lifestyle and supportive measures

• Eat small, frequent meals; avoid large fatty loads that can exacerbate reflux.
• Avoid alcohol, caffeine, and tobacco, which stimulate gastric acid.
• Maintain adequate hydration, especially if diarrhea is prominent.
• Supplement fat‑soluble vitamins (A, D, E, K) if malabsorption is evident.

Living with Zollinger‑Ellison Syndrome (Benign)

While the condition is chronic, most patients lead active lives with proper treatment.

Daily management tips

• Medication adherence: Take PPIs exactly as prescribed; never skip doses.
• Regular monitoring: Serum gastrin and fasting gastric pH should be checked every 6‑12 months, or sooner if symptoms change.
• Nutrition: A dietitian can help tailor a low‑acid, nutrient‑dense plan. Consider a low‑fat diet if steatorrhea is present.
• Stress reduction: Stress can worsen ulcer pain; incorporate relaxation techniques (e.g., yoga, mindfulness).
• Follow‑up imaging: Annual CT/MRI or somatostatin PET scans for tumor surveillance, especially in MEN‑1 patients.
• Vaccinations: If you receive immunosuppressive therapy (e.g., chemo), stay up‑to‑date on flu, pneumonia, and COVID‑19 vaccines.

Support resources

National organizations such as the Gastrinoma Cancer Foundation and MEN‑1 Alliance provide patient forums, educational webinars, and financial assistance.

Prevention

Because most gastrinomas arise spontaneously, primary prevention is limited. However, you can reduce overall risk of neuroendocrine tumors and mitigate complications:

• Quit smoking and limit alcohol consumption.
• Treat H. pylori infection promptly (CDC guidelines).
• Screen family members for MEN‑1 if a known mutation exists; early genetic counseling enables surveillance.
• Maintain a healthy weight and balanced diet to support immune function.

Complications

If left untreated or poorly controlled, ZES can lead to serious health problems:

• Perforated peptic ulcer: Life‑threatening abdominal emergency.
• Gastrointestinal bleeding: May require transfusion or endoscopic intervention.
• Severe malabsorption: Leads to deficiencies (iron, B12, calcium) and osteoporosis.
• Recurrent or metastatic gastrinoma: About 20‑30 % become malignant; metastasis to liver or lymph nodes worsens prognosis.
• Electrolyte disturbances: Chronic diarrhea can cause hypokalemia and metabolic alkalosis.

When to Seek Emergency Care

References

• Mayo Clinic. Zollinger‑Ellison syndrome. Accessed June 2026.
• National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Zollinger‑Ellison Syndrome. 2025.
• American College of Gastroenterology. ACG Clinical Guideline: Management of Peptic Ulcer Disease and Gastrinoma. 2024.
• World Health Organization. Neuroendocrine Tumours Fact Sheet. 2023.
• Cleveland Clinic. Zollinger‑Ellison Syndrome. Updated 2024.
• Gastrinoma Cancer Foundation. Clinical resources & patient stories. 2025.