A malignant tumor which arises from pancreatic G cells that produces excess gastrin. Excess gastrin from the tumor cells leads to hyperplasia of fundic parietal cells and increased basal acid secretion. This results in severe peptic ulcer disease. Ulceration can extend to the small intestine and the acidic content of the small intestine can cause the release of secretin.

Two thirds of gastrinomas are malignant and can metastasize to regional lymph nodes and the liver. Gastrinomas are more common in males than females.

Symptoms are similar to peptic ulcer disease. Persistent abdominal pain exists.

Gastroesophageal reflux

Diarrhea – due to excess intraluminal secretions

Steatorrhea and weight loss

Vitamin B 12 malabsorption

Complications: hematemesis, melena, vomiting due to gastric outlet obstruction, peforation.

Fasting serum gastrin measurement is the most sensitive test for ZES. Serum gastrin usually is 50-60 pg/mL, with an upper limit as high as 150 pg/mL. Levels higher than 1000 pg/mL with acid hypersecretion are highly suggestive of ZES

Basal acid output greater than10 mEq/h. A BAO of greater than 15 mEq/h and even as high as 150 mEq/h is indicative of gastrinoma.

Secretin Stimulation test:

In patients with gastrin levels (150-1000 pg/mL) and acid secretion, the secretin stimulation test can help in diagnosis of gastrinoma. Intravenous secretin (2 U/kg) raises serum gastrin levels to higher than 200 pg/mL in patients with gastrinomas.

Proton pump inhibitors (omeprazole, lansoprazole). These are drug of choice for suppressing acid secretion

H2 receptor antagonists. Treatment has been reported to fail in 50% of the patients.

Chemotherapy is indicated in patients with metastasis and in patients who are not fit for surgery. Combination of Streptozocin, 5-Fluorouracil and doxorubicin has been used.

Surgery:

Surgical resection of the localized disease can lead to complete cure.