Vasointestinal Polypeptide Secreting Tumours

Vasointestinal polypeptide (VIP) secreting tumours (VIPomas) are rare functioning neuroendocrine tumours (NET) The majority arise from the tail of pancreas. Frequently they have metastasized at presentation and may prove challenging to diagnose and manage. The VIP causes a syndrome of profound and chronic, watery diarrhoea which persists despite fasting. Characteristic electrolyte abnormalities occur including: dehydration, hypokalaemia, achlorhydria, acidosis with hypercalcaemia, and hyperglycaemia. These may be life-threatening. Patients may also present with lethargy, weakness, nausea, abdominal pain, and weight loss. Diagnosis requires the clinical picture, fasting VIP level, multimodal imaging including CT, somatostatin receptor scintigraphy, and MRI. Treatment goals are to initially correct dehydration and electrolyte abnormalities. Control of diarrhoea may be achieved using octreotide. Surgical resection with curative intent should be offered where able. For metastatic disease options should be discussed in a NET specific multidisciplinary team meeting (MDT) and include targeted, loco-regional, and peptide receptor radionuclide therapies.