Pancreas: A Multidisciplinary Approach to Canine Insulinoma

Introduction
The most common pancreatic surgery is the removal of pancreatic tumors and this lecture will focus on the treatment of insulinoma (INS). Insulinoma are insulin-secreting tumors and originates from endocrine b-cells from the islets of Langerhans in the pancreas. INS are uncommon in dogs and very rare in cats. Primary canine INS are commonly solitary tumors and their diameter is usually smaller than 2.5 cm. Most INS are located in the left or right pancreatic lobe. In general canine, INS are considered to be malignant in more than 95% of cases, because they almost always tend to metastasize, even though they may lack histological criteria of malignancy. INS hypersecrete insulin and cause an increased insulin concentration in the blood. Normally when blood glucose concentrations decrease, insulin secretion is inhibited. Neoplastic b-cells are less sensitive to the negative feedback of low blood glucose concentrations and secrete inappropriately high amounts of insulin despite declining blood glucose concentrations resulting in profound hypoglycemia. Clinical signs of canine INS often occur intermittently. In the initial stages, hypoglycemic episodes are preceded by fasting, exercise, excitement, or stress, because those situations lead to increased glucose utilization. Between hypoglycemic attacks affected dogs usually do not have clinical signs. The mean duration of clinical signs prior to diagnosis is 3.6 months (range, 1 day – 3.5 years).  [...]