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(Werner-Morrison Syndrome)


Anthony Villano

, MD, Fox Chase Cancer Center

Reviewed/Revised Oct 2023

A vipoma is a non-beta pancreatic islet cell tumor secreting vasoactive intestinal peptide (VIP), resulting in a syndrome of watery diarrhea, hypokalemia, and achlorhydria (WDHA syndrome). Diagnosis is by serum VIP levels. Tumor is localized with CT and endoscopic ultrasound. Treatment is surgical resection.

Symptoms and Signs of Vipoma

The major symptoms of vipoma are prolonged massive watery diarrhea (fasting stool volume > 750 to 1000 mL/day and nonfasting volumes of > 3000 mL/day) and symptoms of hypokalemia Symptoms and Signs Hypokalemia is serum potassium concentration < 3.5 mEq/L (< 3.5 mmol/L) caused by a deficit in total body potassium stores or abnormal movement of potassium into cells. The most common... read more , metabolic acidosis Symptoms and Signs Metabolic acidosis is primary reduction in bicarbonate (HCO3), typically with compensatory reduction in carbon dioxide partial pressure (Pco2); pH may be markedly low or slightly... read more , and dehydration. In half of patients, diarrhea is constant; in the rest, diarrhea severity varies over time. About 33% of patients have diarrhea < 1 year before diagnosis, but 25% have diarrhea 5 years before diagnosis.

Lethargy, muscular weakness, nausea, vomiting, and crampy abdominal pain occur frequently.

Diagnosis of Vipoma

  • Confirmation of secretory diarrhea

  • Serum vasoactive intestinal peptide (VIP) levels

  • Endoscopic ultrasonography, positron emission tomography (PET), or scintigraphy can localize

Patients with elevated VIP levels should have tumor localization studies, such as endoscopic ultrasonography, PET, and octreotide scintigraphy or arteriography to localize metastases.

Electrolytes and complete blood count should be measured. Hyperglycemia and impaired glucose tolerance occur in 50% of patients. Hypercalcemia Hypercalcemia Hypercalcemia is a total serum calcium concentration > 10.4 mg/dL (> 2.60 mmol/L) or ionized serum calcium > 5.2 mg/dL (> 1.30 mmol/L). Principal causes include hyperparathyroidism... read more occurs in 50% of patients.

Treatment of Vipoma

  • Fluid and electrolyte replacement

  • Octreotide

  • Surgical resection for localized disease

Initially, fluids and electrolytes must be replaced. Bicarbonate must be given to replace fecal loss and avoid acidosis. Because fecal losses of water and electrolytes increase as rehydration is achieved, continual IV replacement may become difficult.

Octreotide usually controls diarrhea, but large doses may be needed. Responders may benefit from a long-acting octreotide formulation. Patients using octreotide may also need to take supplemental pancreatic enzymes because octreotide suppresses pancreatic enzyme secretion.

Tumor resection is curative in 50% of patients with a localized tumor. In patients with metastatic tumor, resection of all visible tumor may provide temporary relief of symptoms.

The combination of streptozocin and doxorubicin may reduce diarrhea and tumor mass if objective response occurs (in 50 to 60%). Newer chemotherapies under investigation for vipoma include temozolomide-based regimens, everolimus, or sunitinib. Chemotherapy is not curative.

Key Points

  • More than half of vipomas are malignant.

  • Copious watery diarrhea (often 1 to 3 L/day) is common, often resulting in electrolyte abnormalities and/or dehydration.

  • Patients with confirmed watery diarrhea should have their serum vasoactive intestinal peptide (VIP) levels measured (ideally during a bout of diarrhea).

  • Localize tumors with endoscopic ultrasonography, positron emission tomography (PET), or octreotide scintigraphy or arteriography.

  • Remove tumors surgically when possible and suppress diarrhea with octreotide.

Drugs Mentioned In This Article

Drug Name Select Trade
Bynfezia, Mycapssa, Sandostatin, Sandostatin LAR
Adriamycin, Adriamycin PFS, Adriamycin RDF, Rubex
Afinitor , Afinitor DISPERZ, Zortress
NOTE: This is the Professional Version. CONSUMERS: View Consumer Version
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