Hyperinsulinemic hypoglycemia secondary to multiple beta cell adenomas in a boxer bitch

ABSTRACT

Background: The most frequent pancreatic tumours are derived from insulin-secreting β cells, commonly called insulinomas; these are characterised by high insulin secretion causing hypoglycemia and clinical signs such as seizures,tremors, weakness, and polyphagia, among others. In dogs, this tumour represents <0.5% of neoplasias; the majority aresolitary carcinoma masses and rarely adenomas. Insulin-secreting tumours are usually diagnosed in middle-aged or olderdogs. There is no apparent sex predilection for the disease and it has been mainly reported in medium to large breeds.Independently of whether they are adenomas or carcinomas, dogs have the same disease-free time and survival time andthe prognosis is poor.Case An 8-year-old female Boxer was brought to the University Veterinary Hospital with a history of weakness, tremors,and generalised convulsions. Physical examination, CBC and urinalysis revealed no abnormalities. In the blood chemistryprofile, hypoglycemia was detected along with hyperinsulinemia. An abdominal ultrasound revealed the presence of twoabnormal masses located in the pancreas. The insulinglucose ratio was 59.8. Exploratory celiotomy was performed andtwo masses were located in the mesentery, adjacent to the left pancreatic lobe, and a third was in the pancreatic tissue ofthe same lobule. All masses were resected during the same surgery. Cytology of the masses coincided with apparentlymalignant insulinoma, however, the histopathological and immunohistochemically report indicated an insulin-secretingadenoma. The patient improved clinically and remained stable for approximately 545 days, after which seizures relapsedand a new treatment was not approved. The patient died 575 days after surgery.Discussion: In dogs, pancreatic islet cell tumours correspond to endocrinologically active neoplasm that secrete hormonesand are associated with functional disorders (hyperinsulinemia) in relation to hypoglycemia...