Zollinger-Ellison syndrome

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Zollinger-Ellison syndrome

Endocrine system


Zollinger-Ellison syndrome


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Zollinger-Ellison syndrome

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USMLE® Step 1 style questions USMLE

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A 47-year-old woman comes to the physician due to midline abdominal pain that has been ongoing for several months. The pain is described as a burning sensation and worsens after meals. As a result, the patient has been eating less and has experienced a 5 kg (11 lb) weight loss. She has a history of peptic ulcer disease, which was diagnosed last year. She was prescribed omeprazole but has not noticed an improvement in symptoms after initiating therapy. Medical history is also notable for low back pain. Vitals are within normal limits. Physical examination reveals mild tenderness to palpation of the epigastric region. An endoscopy is performed and shows multiple ulcers in the stomach and duodenum. A urea breath test is negative. Administration of intravenous secretin is followed by an increase in serum gastrin levels by 200 pg/mL. Which of the following is the most likely cause of this patient’s symptoms?  

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Multiple endocrine neoplasias (MEN syndromes) p. 359

Zollinger-Ellison syndrome p. 357

Peptic ulcer disease p. 389

Zollinger-Ellison syndrome p. 359


Zollinger-Ellison syndrome p. 359

Zollinger-Ellison syndrome p. 359

duodenal ulcers p. 389

gastrin in p. 380

MEN 1 syndrome p. 359

proton pump inhibitors for p. 408


Zollinger-Ellison syndrome, named after Dr. Zollinger and Dr. Ellison - the two surgeons who first described it, is a rare endocrine disorder where there’s actually three interrelated pathologies.

First, there’s a gastrinoma, which is a gastrin-secreting tumor.

Second, the gastrinoma leads to increased gastric acid secretion from parietal cells.

Third, the excess gastric acid causes peptic ulcers.

Normally, the inner wall of the entire gastrointestinal tract is lined with mucosa, which consists of three cell layers.

The innermost layer is the epithelial layer and it absorbs and secretes mucus and digestive enzymes.

The middle layer is the lamina propria and it contains blood and lymph vessels.

The outermost layer of the mucosa is the muscularis mucosa, and it is a layer of smooth muscle that contracts and helps with the breakdown of food.

In the stomach, there are four regions - the cardia, the fundus, the body, and the pyloric antrum.

There’s also a pyloric sphincter, or valve, at the end of the stomach which closes while eating, keeping food inside for the stomach to digest.

The epithelial layer in different parts of the stomach contains different proportions of gastric glands which secrete a variety of substances.

Having said that, the cardia contains mostly foveolar cells that secrete mucus which is mostly made up of water and glycoproteins.

The fundus and the body have mostly parietal cells that secrete hydrochloric acid and chief cells that secrete pepsinogen, an enzyme that digests protein.

Finally, the antrum has mostly G cells that secrete gastrin in response to food entering the stomach.

These G cells are also found in the duodenum and the pancreas, which is an accessory organ of the gastrointestinal tract.

Gastrin stimulates the parietal cells to secrete hydrochloric acid, and also stimulates the growth of glands in the epithelial layer.


Zollinger-Ellison syndrome is a rare endocrine disorder characterized by a triad of one or more gastrinomas, increased gastric acid secretion, and peptic ulcers. The main symptom is epigastric pain from peptic ulcers, but also includes steatorrhea, weight loss, gastrointestinal bleeding, and diarrhea due to incomplete digestion and absorption. Zollinger-Ellison syndrome can be treated with acid-lowering medications and surgery to remove solitary tumors. Treatment involves reducing the production of stomach acid with medications, removing the tumor through surgery.


  1. "Robbins Basic Pathology" Elsevier (2017)
  2. "Harrison's Principles of Internal Medicine, Twentieth Edition (Vol.1 & Vol.2)" McGraw-Hill Education / Medical (2018)
  3. "Pathophysiology of Disease: An Introduction to Clinical Medicine 8E" McGraw-Hill Education / Medical (2018)
  4. "CURRENT Medical Diagnosis and Treatment 2020" McGraw-Hill Education / Medical (2019)
  5. "Gastrinoma (Duodenal and Pancreatic)" Neuroendocrinology (2006)

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