Case report of a guinea pig (Cavia porcellus) with a surgically treated insulinoma

Background: Insulinomas in guinea pigs are poorly documented. Case description: A 2.5-year-old female guinea pig presented with severe hypoglycemia, head tilt, weakness, weight loss, hypothermia and a radiodense abdominal structure. The serum insulin concentration was measured with unsatisfactory results. The animal was treated for acute hypoglycemia with clinical stabilization, prednisolone, diazoxide, and frequent syringe feeding, but severe hypoglycemia recurred and an exploratory laparotomy was performed. Two pancreatic masses were located and removed. The excised tissue was histologically diagnosed as insulinoma with osseous metaplasia. Four months postsurgery the same clinical signs and hypoglycemia recurred. Previous medical treatment was prescribed; however, 20 days later the animal worsened and euthanasia was elected. Conclusions and case relevance: Nodulectomy of an insulinoma in a guinea pig can achieve temporal remission of clinical signs. In guinea pigs with insulinoma head tilt may occur frequently, X-rays may be helpful in revealing a pancreatic mass, and treatment with prednisolone and diazoxide could help in disease management.