ODP553 Hypoglycemia after sleeve gastrectomy: a rare case of an insulinoma

Abstract

Abstract Background The obesity pandemic has become a great topic of interest due its implications for quality of life, comorbidities, increasing mortality and the economic impact on health services worldwide(1). Laparoscopic sleeve gastrectomy (LSG) has been proposed as an effective and durable treatment for severe obesity and glucose metabolism disorders, achieving weight loss due to its restrictive and humoral effects (2). Its prevalence has increased from 5 to 37% since 2008 (3). One common complication after bariatric surgery (BS) is the postprandial hyperinsulinemic hypoglycemic state (4). While rare, insulinomas can cause it, where symptoms are more common during the fasting state; thus, evaluation of insulin secretion is needed to exclude dumping syndrome or nesidioblastosis. Until now, this is the first report of insulinoma after LSG. Clinical Case We here present 43-year-old women who was referred to the Obesity Clinic two years after LSG was performed. She had symptoms of hypoglycemia predominantly in the fasting state with a documented glycemic level of less than 30 mg/dl, compatible with Whipple's Triad. Initially, we suspected dumping syndrome but after documentation of a second low fasting plasma glucose, we decided to perform a 72-hour fasting test, which tested positive. Computed tomography and endoscopic ultrasound were performed, identifying the presence of a homogeneous hypoechoic semioval tumoral lesion in the pancreas. The diagnosis was compatible with insulinoma. A laparoscopic enucleation of insulinoma was performed, and after that, the hypoglycemic symptoms and blood sugar levels improved, remaining asymptomatic until now. The histopathological report described a well-differentiated grade 2 neuroendocrine tumor with positive chromogranin and synaptophysin and Ki67 immunopositivity in 4% of the neoplastic cells. Conclusion This is the first case of insulinoma after sleeve gastrectomy, the suggested physiopathology is due to a combination of increased plasma concentrations of incretins, mainly glucagon-like peptide 1 (GLP-1), and an accelerated release of nutrients in the proximal duodenum (5). Although this is a very rare case condition, clinicians must be aware of it, especially if the patient has hypoglycemic symptoms during the fasting state.