Malignant glucagonoma associated with hyperglycaemia, hypertriglyceridaemia, Candidiasis and bacterial pneumonia in a 12-year-old Arabian gelding

A 12-year-old Arabian gelding was presented for severe, rapid weight loss and polyuria. Physical examination revealed a body condition score of 1/9 with severe muscle wasting, moderate tachycardia, profound hyperglycaemia and hypertriglyceridaemia. The horse's clinical condition deteriorated rapidly resulting in euthanasia 16 h following admission. Post-mortem examination revealed multifocal nests of neoplastic endocrine cells within the liver which had immuno-positive glucagon reactivity. Based on the combination of cachexia, marked hyperglycaemia and glucagon-positive neoplastic cells, a diagnosis of malignant glucagonoma, which was presumed to be functional, was made. This is the first case of malignant glucagonoma to be reported in horses.