SUN-623 False Hope: Paraneoplastic Hypoglycemia In Type 2 Diabetes Masquerading As Diabetes Remission

Abstract Disclosure: L. Cheong: None. S. Siow: None. P. Eng: None. V. Ramadoss: None. A. Tan: None. C. Khoo: None. D. Deepak: None. W. Cheong: None. Introduction The American Diabetes Association defines diabetes remission as a return of HbA1c to <6.5%, persisting for at least 3 months in the absence of glucose-lowering pharmacotherapy. However, certain conditions, such as non-islet cell tumor hypoglycemia (NICTH), can complicate the assessment of diabetes remission. NICTH is a rare paraneoplastic phenomenon associated with epithelial or mesenchymal tumors. It typically manifests as hypoglycemia and may occur in patients with diabetes. We report a case of NICTH in a man initially thought to be in diabetes remission. Case Report A 50 year old man with a 4 year history of diabetes (HbA1c 12% at diagnosis) reported improvement after 1 year of oral glucose lowering agents (OGLA), achieving a HbA1c of 5%. His OGLA were discontinued, and he was labeled as achieving remission, maintaining HbA1c <6% without treatment or lifestyle changes. In the recent 6 months, he developed new onset blurred vision, tremors, and diaphoresis before meals, relieved with food, with self documented capillary blood glucose <3mmol/L and a 5kg weight gain. Clinical examination revealed a hard suprapubic mass. To investigate his hypoglycemia, he underwent a supervised fast, where venous glucose dropped to 2.6mmol/L at 7 hours, associated with appropriately low serum C peptide of 31pmol/L (<200pmol/L) and serum insulin <1.6mU/L (<3mU/L), but undetectable serum beta hydroxybutyrate levels. IV glucagon 1mg administered at fast cessation resulted in a 2.1mmol/L rise in venous glucose (2.6 to 4.7mmol/L), indicating an insulin-like effect. Computed tomography of the abdomen revealed a 15.5x11.5x13.4cm lobulated mass in the lower abdomen. Serum insulin like growth factor 1 (IGF1) was 34µg/L (79-205µg/L), and serum insulin like growth factor 2 (IGF2) was 1154ng/mL (333-967ng/mL), with IGF2:IGF1 ratio of 33 (<3), confirming IGF2 excess. He was advised on frequent meals containing complex carbohydrates and started on prednisolone to prevent fasting hypoglycaemia, prior to open resection of the pelvic tumor. Histology revealed a solitary fibrous tumour with immunohistochemical staining of patchy STAT-6 expression with NAB2-STAT6 gene fusion. Post-operatively, his hypoglycemic episodes resolved, and repeat IGF2 levels are pending. Conclusion NICTH can mimic spontaneous remission of diabetes and progress to symptomatic hypoglycemia. Clinicians should maintain a high index of suspicion for underlying hypoglycemic disorders in persons with diabetes who develop apparent remission or recurrent hypoglycemic episodes despite medication reduction or cessation. Presentation: Sunday, July 13, 2025