What is Zollinger-Ellison Syndrome? | Gastroenterology

Zollinger-Ellison Syndrome

Overview of Zollinger-Ellison syndrome

Zollinger-Ellison Syndrome (ZES) is a rare condition that affects the digestive system. It is characterized by the formation of tumours called gastrinomas. Gastrinomas are commonly found in the pancreas and the upper part of the small intestine, also known as the duodenum.

It is possible to have only one tumour, but having multiple tumours is very common. Half of these tumours are not cancerous or benign.

Gastrinomas produce large amounts of a hormone called gastrin. Gastrin stimulates the excessive production of gastric acid. Some stomach acid is needed to break down and digest food, but most of it can lead to ulcers.

People with ZES have a higher risk of developing peptic ulcers than people without this syndrome. Peptic ulcers are painful ulcers in the lining of the gastrointestinal tract.

Symptoms of Zollinger-Ellison syndrome

Symptoms are usually digestive in nature. The two most common reliable symptoms of ZES are abdominal pain and diarrhoea. Other symptoms include:

  • Bloating and burping
  • Nausea
  • Vomiting
  • Weight loss for no apparent reason
  • Loss of appetite

The symptoms of ZES are sometimes confused with the more common peptic ulcer disease or gastroesophageal reflux disease. GERD is a chronic condition in which acid from the stomach backs up into the oesophagus. The symptoms of ZES are more severe and less responsive to standard treatments than these other disorders.


The exact cause of Zollinger-Ellison Syndrome is unknown. But the sequence of events that occur in Zollinger-Ellison Syndrome is clear. The syndrome begins when one or more tumours (gastrinomas) form in the pancreas or duodenum or other sites, such as the lymph nodes adjacent to the pancreas.

Your pancreas is behind and below your stomach. It produces the enzymes necessary to digest food. The pancreas produces many hormones, including a hormone called insulin, which helps regulate glucose in the blood.

Digestive juices from the pancreas, liver, and gallbladder mix in the duodenum, the part of the small intestine next to the stomach. This is where digestion peaks.

Tumours with Jolinger-Ellison syndrome secrete large amounts of the hormone gastrin. The increased gastrin causes the stomach to produce too much acid. Too much acid can lead to peptic ulcers and sometimes diarrhoea.

In addition to causing high acid production, tumours are often cancerous (malignant). Although tumours can grow slowly, cancer can spread to other places, usually to nearby lymph nodes or the liver.

Diagnosing this syndrome

If your doctor suspects ZES, they will order a blood test to check for elevated levels of gastrin. If excessive gastrin is detected, imaging tests will be performed to determine the size and location of the gastrinomas. These tests can include:

  • CT scan
  • MRI scan
  • Endoscopic ultrasound, which involves feeding a thin ultrasound probe down your throat.

If you need an endoscopic ultrasound, your throat may be numbed with a liquid anaesthetic, or you may receive light sedation in an outpatient centre.


Treatment for Zollinger-Ellison Syndrome includes hormone-secreting tumours and the ulcers they cause.

Treatment of tumours

An operation to remove the tumours that occur in Zollinger-Ellison requires a skilled surgeon because the tumours are often small and difficult to locate. If you have just one tumour, your doctor may be able to remove it surgically, but surgery may not be an option if you have multiple tumours or tumours that have spread to your liver. On the other hand, even if you have multiple tumours, your doctor still may recommend removing a single large tumour.

Treatment of excess acid

Excess acid production can almost always be controlled. Medications known as proton pump inhibitors are the first line of treatment. These are effective medications for decreasing acid production in Zollinger-Ellison syndrome.

What are the complications of Zollinger-Ellison syndrome?

A person who has Zollinger-Ellison syndrome may have only one gastrinoma or may have several. Approximately 25% to 30% of ZES patients also have a genetic (inherited) disorder known as “multiple endocrine neoplasia type 1,” which also causes tumours in the pituitary and parathyroid glands.

Another complication of ZES is that more than half of single gastrinomas are malignant (cancerous). These malignant gastrinomas can spread to other parts of the body, including the liver, lymph nodes, spleen, bones, or skin.

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