A glucagonoma is a very rare pancreatic islet cell tumour secreting excessive amounts of glucagon. It is characterised by a high blood glucose concentration as glucagon antagonises the effects of insulin. This accounts for some of the symptoms observed in the glucagonoma syndrome, but the majority remain unexplained.
The tumours arise predominantly in the body and tail of the pancreas. They are generally large (>4cm diameter) and 70% are malignant. At diagnosis, 50% of individuals will have metastatic deposits in the liver.
The estimated prevalence of glucagonoma is 1 in 20, 000, 000 people. It affects mainly adults (age range of 19 - 72 years) but the peak incidence is between 40 and 60 years of age.
The cause is as yet unknown, but like all tumours, a genetic aetiology is presumed to be at least partially responsible.