Hypoglycaemic brain lesions in a dog with insulinoma

A 5-year-old female Collie dog showed excessive salivation, vomiting and neurological signs, including hind-limb weakness, mental dullness and subsequent recumbency with paddling movements of the limbs. Blood glucose and insulin concentrations were 35 mg/dl and 70.0 microU/ml, respectively. At necropsy, two masses, one at the caudal edge of the pancreas and the other in the omentum, were found and diagnosed as insulinoma. Histological examination of the brain showed early signs of acute neuronal necrosis exclusively in the superficial layers of the cerebral cortex, in addition to spongy changes in the dentate gyrus of the hippocampus. The light microscopical findings were identical in character and distribution with those of naturally occurring hypoglycaemia in humans and experimentally induced hypoglycaemia in animals.