SUN-906 To Function or Not to Function: A Rare Case of Metachronous Hormone Syndrome

This is a 51-year-old female with a history of metastatic neuroendocrine tumor of the pancreas diagnosed four years ago who was admitted to the to the hospital for hypoglycemia. She initially had come to the hospital for alternative treatment of her disease using PRRT (peptide receptor radionuclide therapy). Prior to receiving treatment the patient had been asymptomatic. After receiving her first dose of PRRT the patient developed acute encephalopathy. Upon evaluation she was noted to be oriented only to person, lethargic and confused. Finger stick blood glucose at the time of her symptoms had read 17. The patient was immediately placed on D10 with improvement of her symptoms and increase of glucose to the 70s. An attempt was made to wean the patient off of dextrose however the patient continued to experience persistent hypoglycemia. Thus investigation of an insulin-secreting tumor was done. C-peptide was 3.98 ng/mL (0.81 - 5.30 ng/mL), insulin level was 26.7 uU/mL (3.0-16 uU/mL) and proinsulin level was 556 pmol/L (<22 pmol/L), while her serum glucose was below 45. Given her biochemical markers as well as improvement in glucose when treated the patient was started on Diazoxide for presumed insulinoma. Due to intolerance to the medication she was switched to Octreotide with success. Here we present an unusual case of Metachronous Hormone Syndrome (MHS) in a patient who at presentation of her diagnosis was already found to have metastatic pancreatic neuroendocrine tumor. Typically NET present in the 4(th) to 6(th) decades of life and have the potential to secrete peptide hormones. Occasionally patients with tumors that appear to be nonfunctional develop symptoms of hormone secretion later in their disease such as our patient. Furthermore it is uncommon for a patient to present with metastatic NET; such was not the case for our patient. Metachronous hormone syndrome is not fully understood but may be an indication of tumor progression. In addition its mechanism of action is unknown and its been theorized to be induced by anti-tumor treatments. Perhaps this case may allow us to better understand MHS in a broader context, as this patient was found to have progression of her disease when she initially was diagnosed 4 years ago and recently presented with symptoms consistent with an insulinoma. Lastly her case may further guide us in studying various treatments for NET and their role in triggering MHS. References 1. De Mestier, Louis et al. Metachronous hormone syndromes in Patients With Pancreatic Neuroendocrine Tumors: A Case Series Study. Annals of Internal Medicine. 2015; 162 (10): 682-689. 2. Mathur, A, Gorden, P and Libutti SK. Insulinoma. The Surgical Clinics of North America. 2009-10-01, Volume 89, Issue 5, Pages 1105- 1121. 3. Igarashi, H, Hiijoka, M, Lee, L and Ito, T. Biotherapy of pancreatic neuroendocrine tumors using somatostatin analogs. Journal of Hepatobilliary Pancreatic Sciences. 2015, Volume 22, Issue 8.