SAT-229 An Adolescent Female with Hypoglycemia and a Massive Intraabdominal Tumor: A Case Report of Non- Islet Cell Tumor Hypoglycemia

Abstract Disclosure: M. Yogev Lifshitz: None. D.B. Cameron: None. C. Harwood: None. J. Vakharia: None. R. Whooten: None. Background: Non-islet cell tumoral hypoglycemia (NICTH) is a rare cause of hypoglycemia in adults and even more rare in the pediatric population. Hypoglycemia occurs due to increased secretion of insulin-like growth factor 2 (IGF2). Management depends on definitive management and there is wide variation in success with supportive care. Case presentation: A previously healthy 12 year old female presented with acute change in mental status and a distended abdomen. She was noted to have hypoglycemia to 30 mg/dl that responded to IV dextrose. Cross-sectional imaging demonstrated a large heterogenous enhancing mass, measuring 21.5 x 10.9 x 28.4 cm in the abdomen and pelvis without clear origin. At the time of hypoglycemia (blood glucose 50 mg/dL), a critical sample demonstrated absent ketones and undetectable insulin and c-peptide. Low cortisol 3.9 ug/dL at the time of hypoglycemia stimulated appropriately to 24.19 ug/dL. Repeat morning cortisol was also low (2.5 ug/dL). Of note, IGF1/IGF2 ratio measured via both ELISA and mass spectrometry was 1:8.5, below the threshold of NICTH diagnosis. She had an exaggerated response to glucagon stimulation, with increase from 50 mg/dl to 144mg/dl. Given the size of tumor and unclear anatomic origin, she underwent core needle biopsy that demonstrated Spindle cell neoplasm of uncertain malignant potential. A fusion assay was negative for a viable immunotherapy target. Attempt to wean off dextrose-containing fluids resulted in repeated hypoglycemia events and thus prolonged hospitalization while awaiting definitive management of tumor. She was eventually stabilized on overnight dextrose fluids with glucose infusion rate of 3 mg/kg/min, and daytime frequent oral intake along with continuous glucose monitoring. She was discharged home while awaiting surgical planning. Perioperatively, she received stress dosing of hydrocortisone. Abdominal exploration demonstrated a 5kg, 25cm abdominal tumor emanating from the retroperitoneum that was adhered to the sigmoid colon but not invading it. Intra-operatively, glucose infusion rate was decreased from 3 to 1.5 mg/kg/min due to hyperglycemia. Following resection, she was successfully transitioned to full oral diet without any need for intravenous fluids. Pathology demonstrated a Spindle cell tumor showing smooth muscle differentiation without malignant features. Repeat morning cortisol after resection was 11.3 ug/dL. Follow-up imaging three months post-operative demonstrated no evidence of residual or recurrent disease. Conclusion: This presentation illustrates the importance of definitive tumor resection in cases of NICTH and highlights the importance of high level of suspicion even in the setting of lower ratios of IGF2/IGF1describes a successful short-term management with nutrition and IV fluids and highlights the effects of IGF2 secreting tumors on cortisol levels as well as glucose. Presentation: Saturday, July 12, 2025