Vipoma: A Rare Tumour, a Rarer Cause of Acute Diarrhoea

Vasoactive intestinal peptide tumours (VIPomas) are rare pancreatic neuroendocrine tumours with an estimated incidence of between 0.2 to 0.5 per million per year that usually present with a conglomerate of findings related to the excessive secretion of vasoactive intestinal peptide (VIP) including profuse watery diarrhoea, dehydration, hypokalemia and hypoclorhydria occasionally referred to as VIPoma syndrome. VIPomas are usually considered as a cause of chronic diarrhoea and the onset of symptoms is often described as insidious. Here we present a patient who developed acute diarrhoea with typical symptoms and laboratory findings of a VIPoma, later radiologically and histologically confirmed. Despite demonstrating the typical features of severe watery diarrhoea, dehydration and hypokalemia our case was atypical in its rapidity of onset and progression of the clinical syndrome. In view of the acuteness in onset and severity of her biochemical derangements the patient ended up developing an unfavourable outcome despite the absence of metastasis and a relatively young age which are usually regarded as good prognosticators.