A gastrinoma is a tumor usually in the pancreas or duodenum (the first segment of the small intestine) that produces excessive levels of the hormone gastrin, which stimulates the stomach to secrete acid and enzymes, causing peptic ulcers.
These tumors arise from cells in the pancreas that produce gastrin.
Symptoms are similar to those caused by peptic ulcers, including pain and bleeding.
Diagnosis includes blood and imaging tests.
Treatment includes medications to reduce acid in the stomach and sometimes surgery and chemotherapy.
The survival rate is high if the tumor is completely removed.
Gastrinomas are a type of pancreatic endocrine tumor. About half of the tumors are cancerous. Gastrinomas usually are small and grow slowly.
Sometimes a gastrinoma occurs as part of multiple endocrine neoplasia, a hereditary disorder in which tumors arise from the cells of various endocrine glands, such as the insulin-producing cells of the pancreas.
Symptoms of Gastrinoma
The excess gastrin secreted by the gastrinoma causes the stomach to produce far too much acid. This overproduction of acid can result in Zollinger-Ellison syndrome.
In Zollinger-Ellison syndrome, a person has symptoms of aggressive peptic ulcers (such as pain or bleeding) in the stomach, duodenum, and elsewhere in the intestine. However, as many as 25% of people with Zollinger-Ellison syndrome do not have an ulcer when the diagnosis is made. Rupture, bleeding, and obstruction of the intestine can occur and can be life threatening. For more than half of the people with a gastrinoma, symptoms are no worse than those experienced by people with ordinary peptic ulcer disease. In 25 to 40% of people, diarrhea resulting from the excess acid production is the first symptom.
Diagnosis of Gastrinoma
Blood tests
Imaging tests
A doctor suspects a gastrinoma when a person has frequent peptic ulcers or several peptic ulcers that do not respond to the usual ulcer treatments. Blood tests to detect abnormally high levels of gastrin are the most reliable diagnostic tests.
Once blood tests diagnose gastrinoma, doctors try to locate the tumor using several imaging techniques, such as computed tomography (CT) of the abdomen, scintigraphy (a type of radionuclide scanning), endoscopic ultrasonography, positron emission tomography (PET) scans, and arteriography (an x-ray taken after a radiopaque dye is injected into an artery). These tumors may be difficult to find, however, because usually they are small.
Treatment of Gastrinoma
Medications to reduce levels of stomach acid
Sometimes surgical removal
Sometimes chemotherapy
High doses of proton pump inhibitors, which are acid-reducing medications (see table Medications Used to Treat Stomach Acid
If there is only one tumor and the person does not have multiple endocrine neoplasia, doctors usually do surgery to remove the gastrinoma. In such cases, surgical removal cures about 20% of people.
If cancerous tumors have spread to other parts of the body, chemotherapy may help reduce the number of tumor cells and the levels of gastrin in the blood. However, such therapy does not cure the cancer, which is ultimately fatal.
Prognosis for Gastrinoma
If the tumor is completely surgically removed, people have a greater than 90% chance of surviving 5 to 10 years. If the tumor is not completely removed, people have a 43% chance of surviving 5 years and a 25% chance of surviving 10 years.
