Endocrine Abstracts

Introduction: An insulinoma is a rare neuro-endocrine tumour originating in the pancreatic beta-cells with unregulated secretion of insulin resulting in profound hypoglycaemia.

Methods: A search of electronic hospital records identified all patients with a primary diagnosis of insulinoma. Clinic and discharge letters, radiology investigations, laboratory investigations and case notes were reviewed to highlight the presentation, investigations and laboratory investigations of the patients.

Results: Eleven patients had a primary diagnosis of sporadic insulinoma, with a year of diagnosis between 1994 and 2018. Most patients presented with symptoms of dizziness and fainting, with near patient testing of hypoglycaemia. In all patients where laboratory investigations had been performed, there was a laboratory confirmed hypoglycaemia (1.2–2.5 mmol/L), and raised insulin and C-peptide. On initial imaging 6 patients had MRI or CT evidence supporting insulinoma. 4 further patients had normal abdominal imaging on the first scan, however later had CT or MRI evidence, or an arterial blush seen on pancreatic angiogram with one patient. One further patient had no imaging. 8 of the 11 patients were still alive at the time of the search, of the three patients who had died one had metastatic insulinoma, and two patients died of illnesses unrelated to insulinoma.

Conclusions: An insulinoma is a rare but important differential to consider in a patient presenting with recurrent hypoglycaemia.

• Normal imaging does not exclude the diagnosis, particularly in a patient with a history suggestive of insulinoma and hypoglycaemia with raised insulin and C-peptide.

• Functional imaging or pancreatic angiogram may assist with diagnosis in these cases.

• Most patients have a good prognosis following surgical removal with swift resolution of symptoms. Solitary insulinoma related death in our case series was that of metastatic insulnoma, which was already metastasised at the time of presentation.