Endocrine Abstracts

Insulinoma represents one of the most encountered neuroendocrine tumors, but only 4–14% is malignant. The diagnosis is suggested by high serum insulin levels during spontaneous or induced episodes of hypoglycemia and often invasion of lymph nodes and liver metastasis. A 55–year–old female was referred to our center after an episode of hypoglycemia during strumectomy for multinodular goiter. Further questioning revealed few years of Metformin treatment for hyperglycemia, which was stopped after repeated hypoglycemic episodes (3–4/week, Gl min = 20 mg/dl) with remission after fast–acting carbs leading to an increase of 40 kg body weight in the last 5 years. Her family history was positive for pancreatic cancer. Post–strumectomy, the patient developed Gerhardt syndrome and hypoparathyroidism requiring daily i.v Calcium infusion. The 72–hour fast was stopped for symptomatic hypoglycemia (Gl = 41 mg/dl) and an glycemia/insulinemia = 2.34. The A1c = 4.5% confirmed the presence of frequent hypoglycemic episodes. The CT scan revealed a tumor in the uncinate process of the pancreas for which enucleation was performed. Microscopic view was consistent with malignant insulinoma. After surgery, the patient became euglycemic with an A1c of 5.6% after 3 months and 10kg weight loss.

Despite its low incidence, the presence of insulinoma must be suspected in every person with repeated hypoglycemia after exclusion of other causes. The imaging studies and the histopathological exam are mandatory in order to establish localization and its malignant features.