Zollinger-Ellison Syndrome: A Complete Overview

Medically Reviewed By Meredith Goodwin, MD, FAAFP
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Zollinger-Ellison syndrome (ZES) is a rare cancerous condition whereby tumors develop in some of the organs of the digestive system. This causes the stomach to produce too much acid. This article explains the symptoms, causes, and complications of ZES. It also discusses how doctors diagnose this condition, treatment options, and what the outlook for ZES may be.


A person lies on top of their bed with their eyes closed and their hand over their stomach.
Anna Berkut/Stocksy United

ZES tumors can cause further conditions to develop due to high stomach acid levels, such as peptic ulcer disease and gastroesophageal reflux disease (GERD). As a result, ZES symptoms can be similar to the symptoms of these other conditions.

Symptoms of ZES may include:

  • diarrhea, which may be chronic or persistent
  • acid reflux
  • pain in the chest
  • pain in the abdomen or stomach, particularly between the belly button and the center of the chest
  • nausea or vomiting
  • unexplained weight loss
  • peptic ulcers
  • additional symptoms of GERD, such as a cough or regurgitation of acid or stomach contents

Sometimes, diarrhea may be the only noticeable symptom you have.

When to see a doctor

Seek immediate medical care if you experience any of the following symptoms:

These symptoms may indicate a complication of ZES or another severe health condition.

Read more about blood in stool and symptoms of gastrointestinal bleeding.


A medical illustration of gastrinomas in the pancreas.
Illustrated by Jason Hoffman

ZES is caused by the development of tumors known as “gastrinomas” in the duodenum or pancreas. The duodenum is an area of the small intestine. ZES tumors occur in the duodenum more often than in the pancreas.

Gastrinomas produce a hormone called gastrin, which stimulates the stomach cells to produce stomach acid. This stomach acid typically helps you digest food. However, gastrinomas cause an overproduction of gastrin, which results in high levels of stomach acid.

Doctors do not yet know what causes gastrinomas to develop.

However, in around 20–25% of cases, gastrinomas form due to another condition known as multiple endocrine neoplasia type 1 (MEN1) syndrome, or Wermer’s syndrome. This is a rare genetic condition. The remainder of ZES cases are not related to other conditions.

Risk factors

ZES is rare. The National Institutes of Health (NIH) estimate that only between 0.5 to 3 people out of every million receive a diagnosis of ZES each year.

ZES can develop in anyone at any age. However, according to the NIH, the condition is most frequently diagnosed in people between 20–50 years old.

A 2022 review also suggests that more people assigned female at birth may develop ZES than people assigned male at birth.


To diagnose the cause of your symptoms, your doctor will start by asking you questions about your medical and family history and your symptoms. They may then perform a physical exam.

Your doctor may also recommend additional tests. Diagnostic tests to look for ZES or rule out other conditions include:

  • blood tests
  • imaging tests, such as CT or MRI scans
  • stomach acid tests
  • upper gastrointestinal endoscopy
  • endoscopic retrograde cholangiopancreatography
  • angiography

Before you undergo these tests, your doctor may require you to stop taking medications that help manage stomach acid, such as proton pump inhibitors (PPIs) and H2 blockers. However, do not stop taking medications without direction from your doctor.

If you have recurrent peptic ulcers that do not respond to standard ulcer treatment, this may also be a sign of ZES.

Treatment options

Treatment for ZES focuses on treating the tumors and alleviating symptoms.

Your doctor may prescribe a type of medication known as a proton pump inhibitor (PPI) to decrease the acidity in your stomach. They may recommend taking a higher dose at the beginning of your treatment, and then they may reduce the amount you have to take over time.

Some people with ZES may need to take PPIs as a lifelong treatment. PPIs are generally safe, but they can cause side effects, such as:

Other treatment options include surgery to remove the gastrinoma tumors. For some people, this can cure ZES. It may also prevent the tumors from spreading to other organs.

In some cases, you may still need to take PPIs after undergoing surgery to manage stomach acidity.

For people with MEN1 syndrome, doctors may consider surgery only if the tumors are bigger than 2 centimeters. In other cases, surgery may not be an option. This is because people with MEN1 usually have multiple, small tumors, which makes it more challenging to remove them all safely during surgery. Doctors usually focus on the bigger ones with a higher risk of spreading elsewhere.

Additional treatment to stop the spread of the tumors can include:

Possible complications

People with ZES may develop further complications, such as:

  • internal bleeding
  • perforation of your digestive tracts or organs
  • pain
  • malnutrition
  • surgery complications
  • death

Gastrinomas that cause ZES are also cancerous. Without effective treatment, the tumors may spread to other areas of the body, such as:

  • pancreas
  • liver
  • lymph nodes
  • bone
  • other distinct organs

However, additional treatment plans may help to contain this spread and improve your outlook.


The outlook for ZES depends on multiple factors, such as the stage of the gastrinoma and its location.

About 60–90% of gastrinomas are malignant, meaning they are cancerous. Without effective treatment, gastrinomas typically spread to the liver, lymph nodes, or other organs.

However, effective treatment can improve your outlook and reduce the risk of spread or complications.

Contact your doctor for individualized advice regarding your condition and outlook.

What is the survival rate of Zollinger-Ellison syndrome?

The survival rate and life expectancy for someone with ZES can depend on various factors.

If a person with gastrinoma experiences the spread of tumors to the liver, known as metastasis, their survival rate may decrease. According to a 2022 review, about 50% of pancreatic gastrinoma causes liver metastasis, while around 10% of duodenal gastrinomas do. Most gastrinomas affect the duodenum rather than the pancreas.

The same 2022 review suggests that people with ZES who experience liver metastasis have a 15% 10-year survival rate after surgery. However, it goes on to suggest that people without liver metastasis have a 95% 20-year survival rate.

Survival rate refers to the number of people who are still alive for a specific length of time after a particular diagnosis. 

For example, a 5-year survival rate of 50% of people means that half of the people are still alive 5 years after their diagnosis. 

It is important to remember that these figures are estimates and are based on previous medical studies. Talk with your doctor about the outlook for your specific condition. 


ZES is a rare condition in which your stomach produces too much acid due to the presence of tumors known as gastrinomas. Gastrinomas are a type of cancer that can develop in the pancreas and duodenum.

The presence of too much acid in your stomach can cause ulcers, internal bleeding, and the perforation of your digestive tract. Other symptoms of ZES include diarrhea, abdominal pain, and heartburn.

Treatment can include medication with PPIs and surgery to remove gastrinomas and stop their spread. However, surgery may not be an option for everyone.

Contact your doctor for individualized advice regarding ZES. Seek immediate medical care for symptoms of severe pain, chronic diarrhea, or gastrointestinal bleeding.

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Medical Reviewer: Meredith Goodwin, MD, FAAFP
Last Review Date: 2023 Jan 6
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THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
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