PMON38 Severe Refractory Hypoglycemia in a Patient with Metastatic Neuroendocrine Tumor

BACKGROUND: Neuroendocrine tumors(NETs) differ in origin, location, behavior and response to treatment. In most cases, they secrete hormones or vasoactive substances. Pancreatic NETs (PNETs) are rare tumors and account for 1-2% of all pancreatic tumors. They arise from the endocrine tissue of the pancreas. Fifty to seventy percent of PNETs are not functioning. Functioning tumors can secrete insulin, glucagon, gastrin, vasoactive intestinal peptide depending on their origin. Insulinomas are the most common type of PNETs with an incidence rate of 1-4 per 1000,000 per year. They are usually indolent tumors and rarely malignant. Insulinomas are characterized by fasting hypoglycemia with elevated serum insulin and c-peptide levels. Symptoms can range in severity from confusion, visual changes, palpitations, diaphoresis, and tremulousness to seizures, amnesia or coma. CLINICAL CASE: We report a case of a 71 year old male who was referred for an evaluation of ongoing hypoglycemia. He was diagnosed with metastatic carcinoid cancer by fine needle aspiration of the tail of pancreas and liver which showed a well-differentiated neuroendocrine type tumor. A month later, the patient underwent an exploratory laparotomy, pancreatectomy, splenectomy, appendectomy. PNET was identified in the spleen and pancreas. Less than a year later, the neuroendocrine cancer metastasized to the thoracic vertebrae (T8 Biopsy: Positive stains: Pancytokeratin, CD56, Synaptophysin, Chromogranin and Ki-67 [20%]). He received chemotherapy with doxorubicin and streptozocin. He had multiple interventional radiology guided liver chemoembolization. Throughout this time, his hypoglycemia rapidly worsened requiring aggressive medical management. His lab findings (hemoglobin A1C 5.4%, serum glucose 114 mg/dL, c-peptide 26 ng/mL [4.4ng/mL UNL], GFR>60 ml/min/1.73 m2, random insulin levels 123 mIU (24.9 mIU UNL) with serum glucose 108 mg/mL, serum chromogranin A 2616 ng/mL [102 ng/mL UNL]) and clinical progression suggested that his PNETs were insulin producing. He was started on sandostatin and later on diazoxide to control his blood glucose levels. Use of Diazoxide lead to anasarca. Patient was not able to tolerate prolonged fasting due to hypoglycemia that continued to worsen. He required multiple admissions with IV dextrose administration. Later, octreotide was stopped due to concerns of paradoxical hypoglycemia due to glucagon suppression and hypoglycemia initially improved. However, a few weeks later hypoglycemia again worsened and we decided to increase the diazoxide and furosemide. The patient's hypoglycemia continued to progress in frequency and severity and his overall condition continued to deteriorate. The patient therefore chose hospice care and passed away shortly after. CONCLUSION: This is a rare case of rapidly progressing metastatic PNET with severe refractory hypoglycemia in a patient despite treatment with multiple modalities. More research is needed to further characterize PNETs and improve current available management. Presentation: Monday, June 13, 2022 12:30 p.m. - 2:30 p.m.