Postprandial Hypoglycemia: An Unusual Presentation for Insulinoma

Insulinoma is the most common type of islet cell tumor of the pancreas and its incidence is estimated at four per one million persons per year.\udAlthough fasting hypoglycemia is the typical presentation, cases with postprandial hypoglycemia have rarely been reported. A 48-year-old\udwoman was admitted to our department for evaluation of hypoglycemia. Laboratory data suggested a state of postprandial endogenous\udhyperinsulinemic hypoglycemia. Abdominal computed tomography revealed a mass lesion measuring 20 mm at the distal pancreas. A decision\udwas made to perform an arterial calcium-stimulated venous sampling for excluding nesidioblastosis coexisting with a pancreatic incidental\udmass. After that the patient was referred to surgery. Pathological examination revealed a low-grade well-differentiated neuroendocrine tumor\udwith regional lymph node metastasis. Herein, we report a case of malignant insulinoma presenting with postprandial hypoglycemia and discuss\udthe differential diagnosis and possible mechanisms of postprandial hypoglycemia in insulinoma cases