LBODP070 A Rare Neuroendocrine Tumor-Insulinoma

INTRODUCTION: Insulinoma is a rare neuroendocrine tumor, which presents sporadically or as a complex of multiple endocrine neoplasia type 1 syndrome (MEN-1). Most Insulinoma cases present with fasting hypoglycemia and some with both fasting and postprandial hypoglycemia. CASE REPORT: A 48-year-old male with no significant past medical or surgical history presented for an evaluation of hypoglycemia. He was recently seen in the Emergency Room after having a transient ischemic attack-like episode. The patient reported that he was at a family gathering where he was found confused and his blood glucose was checked by a family member with diabetes, which was noted to be 39 mg/ dl. He reported having other such episodes of lesser severity, occurring once or twice a month for many years. His symptoms would typically wake him from sleep, especially during early mornings with diaphoresis. He would take a snack to resolve his symptoms. Except for being overweight, no other abnormal findings were detected on physical examination. Fasting blood work revealed glucose of 42 with elevated insulin, C-peptide, proinsulin levels, and negative beta-hydroxybutyrate and insulin antibodies. An MRI abdomen with contrast demonstrated a 1.2 cm pancreatic lesion in the uncinate process, suspicious for a neuroendocrine tumor. Endoscopic Ultrasound staged the mass in the uncinate process of the pancreas as T1 N0 M0. FNAC showed a few atypical monomorphic cells suggestive of neuroendocrine origin. Immunohistochemical stains on the sample were positive for CD45 while CAM5.2, synaptophysin, and Ki65 were negative. The patient ultimately underwent exploratory laparotomy and resection of the neuroendocrine tumor with partial pancreatectomy. DISCUSSION: The symptoms of hypoglycemia are classified into sympathoadrenal (palpitation, diaphoresis, tremulousness) or neuroglycopenic (confusion, blurry vision, change in behavior, seizures, and amnesia of hypoglycemic episode). The neuroglycopenic symptoms of hypoglycemia mimic transient ischemic attack (TIA). The diagnosis of insulinoma needs biochemical proof of endogenous hyperinsulinemia and localization of the tumor. Surgery is the treatment of choice in resectable tumors. CONCLUSION: This case highlights insulinoma as a rare cause of hypoglycemia and shows the importance of detailed history taking and appropriate investigations in its diagnosis. References: 1. Okabayashi T, Shima Y, Sumiyoshi T, Kozuki A, Ito S, Ogawa Y, Kobayashi M, Hanazaki K. Diagnosis and management of insulinoma. World J Gastroenterol. 2013 Feb 14;19(6): 829-37. doi: 10.3748/wjg. v19. i6.829.2. Mathur A, Gorden P, Libutti SK. Insulinoma. Surg Clin North Am. 2009 Oct;89(5): 1105-21. doi: 10.1016/j. suc.2009. 06. 009.3. huo F, Anastasopoulou C. Insulinoma. [Updated 2021 Jul 18]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Presentation: No date and time listed