Insulinoma in a dog with pre-existing insulin-dependent diabetes mellitus.

A 10-year-old golden retriever with a 3-year history of insulin-dependent diabetes mellitus was presented with recurring episodes of hypoglycemia and seizures. A presumptive diagnosis of an insulinoma was made based on hypoglycemia with concurrent endogenous hyperinsulinemia and unremarkable radiographic and ultrasonographic images of the chest and abdomen. A beta cell carcinoma of the pancreas with metastasis to the liver and a mesenteric lymph node was confirmed by surgery and histopathology.