A vipoma is a rare type of tumor of the pancreas that produces vasoactive intestinal peptide, a substance that causes severe watery diarrhea.
These tumors arise from cells in the pancreas that produce vasoactive intestinal peptide.
The main symptom is watery diarrhea.
Diagnosis includes blood and imaging tests.
Treatment is replacement of fluids and electrolytes and surgery.
Vipomas are a type of pancreatic endocrine tumor.
More than half of these tumors are cancerous (malignant). In about 6% of people, vipoma occurs as part of a disorder called multiple endocrine neoplasia.
Symptoms of Vipoma
The major symptom of vipoma is prolonged massive watery diarrhea. People produce 1 to 3 quarts (1,000 to 3,000 milliliters) of stool per day, causing dehydration. In 50% of people, diarrhea is constant, and in the rest, the severity of the diarrhea varies over time.
Because the diarrhea removes many of the body’s normal salts, people often develop low blood levels of potassium (hypokalemia) and excessively acidic blood (acidosis). These changes can cause lethargy, muscular weakness, nausea, vomiting, and crampy abdominal pain. Some people have flushing.
Diagnosis of Vipoma
Blood tests
Imaging tests
A doctor bases the diagnosis of vipoma on the person’s diarrhea symptoms and finding elevated levels of vasoactive intestinal peptide (VIP) in the blood.
People with elevated levels of VIP should also have the imaging tests endoscopic ultrasonography, positron emission tomography (PET), and octreotide scintigraphy or arteriography (an x-ray taken after a radiopaque dye is injected into an artery) to detect the location of the vipoma.
Treatment of Vipoma
Replacement of fluids and electrolytes
Octreotide
Surgical removal
Initially, fluids and electrolytes (minerals in the blood such as potassium and sodium) must be replaced by vein (intravenously). Bicarbonate must be given to replace that lost in the stool and to prevent acidosis. Because water and electrolytes continue to be lost in the stool as rehydration is achieved, doctors may find it difficult to continually replace water and electrolytes.
Surgical removal of the vipoma cures about 50% of people whose tumor has not spread. Surgery may temporarily relieve symptoms in people whose tumor has spread.
Chemotherapy drugs may reduce diarrhea and the size of the tumor but do not cure the disease.
