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Gastrinoma

Gastrin secreting tumors that occur in the pancreas or the duodenum.

Duodenal wall tumors frequently small and multiple.

Commonly occur in the gastric triangle formed by the junction of the cystic duct and common bile duct, the junction of the second and third parts of the duodenum, and the junction of the body and neck of the pancreas.

Excessive gastrin release from these tumors causes acid by hypersecretion in the stomach causng clinical manifestations.

Patients with gastrinoma will typically present with abdominal pain, diarrhea, heartburn, gastrointestinal bleeding and weight loss.

Neuroendocrine tumor with secretion of gastrin producing the Zollinger-Ellison syndrome.

Approximately 50% of gastronomas or malignant, with lymph nodes the most common sites of metastasis, and approximately 25% of gastrinomas occur as part of the MEN 1 syndrome.

Frequency nearly equivalent to insulinomas at about 1 per 1 million population per year.

Sporadic pancreatic lesions have a greater tendency to be malignant than do duodenal lesions.

Primary lesions on rare occasions can arise in the stomach, jejunum, omentum, peripancreatic lymph nodes, splenic hilum, liver, gallbladder, common bile duct, and ovary.

25% of lesions associated with the MEN-1 syndrome with hyperparathyroidism and pituitary adenomas.

MEN-1 lesions associated with more benign course than sporadic disease.

MEN-1 lesions typically occur at younger age than do sporadic tumors.

50% of lesions are malignant and metastasize to the lymph nodes and liver.

Association with elevated gastrin levels and severe peptic ulcer disease known as Zollinger-Ellison syndrome.

Excess gastrin causes parietal cell hyperplasia, increased basal acid secretion and severe ulcer disease.

Peptic ulcerations may involve the small bowel.

The small intestine acid content is elevated causing secretin release and secondary diarrhea.

Prognosis related to size of primary and the presence of metastases.

5 year survival with liver metastases 20-30%.

In the presence of liver metastases life span less than 1 year.

Localized disease associated with 5 year survival of 90%

Disease in lymph nodes, without liver metastases, associated with 5 year survival of 90%.

Male:female ratios 1.5-2:1.

Initial presentation in individuals 30-50 years of age.

Symptoms in 90-95% that of peptic ulcer disease or its complications such as gastrointestinal bleeding, gastric outlet obstruction, or perforation.

Symptoms may include diarrhea, weight loss, steatorrhea, and vitamin B12 malabsorption.

Chronic gastroesophageal reflux disease may lead to esophageal complications.

Diagnosis with fasting gastrin levels >150 pg/mL.

Gastrin levels can exceed 100,000 pg/mL.

Gastrin levels greater than 1000 pg/mL diagnostic of Zollinger-Ellison syndrome.

Esophagoduodeoscopy provides information, identifying multiple ulcers within the stomach, duodenum, and jejunum,

Endoscopic interventions can help maintain hemostasis of bleeding lesions, by the injection of epinephrine, cauterization and endoscopic clipping.

Most patients with peptic ulcer disease will be placed on proton pump inhibitors for acid suppression.

Endoscopic biopsies of lesions are taken to rule out involvement with H.pylori.

Gastrin levels should be performed, off PPI therapy as they can cause elevation of gastrin.

If patients do not respond to PPIs the addition of octreotide is indicated.

Patients with solitary lesions can undergo surgical resection of the lesion.

Gastrinomas in the multiple neoplasia type I syndrome are usually not candidates for resection as these patients usually have multifocal lesions.

High doses of proton pump inhibitors are typically required to control symptoms of acid reflux.

Piptide radio nuclearide therapy is a valuable tool in the treatment of symptomatic gastrinoma..

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