SAT-561 Insulinoma Masked as Delirium in Elderly Patient With a Pancreatic Neuroendocrine Tumor Successfully Treated With Novel Pancreatic Radiofrequency Ablation

Abstract Disclosure: A. Iyer: None. M. Sadiq: None. T. Latif: None. Case Presentation: An 80-year-old male admitted to hospital with traumatic left ankle fracture. While being NPO for the fixation, he experienced an episode of hypoglycemia needing intravenous dextrose. He later became agitated needing critical care support with continuous intravenous dexmedetomidine. His delirium, attributed to opioid administration, worsened especially during the night. With worsening delirium he had poor oral intake, leading to further hypoglycemia needing treatment and frequent feeds. He was discharged to a rehabilitation facility with instructions to eat regularly later being readmitted the same day due to continued delirium. The intermittent hypoglycemic episodes that had likely been occurring since his initial admission were now considered a possible cause of his delirium. Lab work revealed fasting hyperinsulinemia, with elevated serum insulin level (21.8 mIU/mL), elevated C-peptide (3.6 ng/mL) and plasma glucose of 49 mg/dL. Magnetic resonance cholangiopancreatography and liver ultrasound were unremarkable. Endoscopic ultrasound (EUS) was performed, revealing a 1.8 cm pancreatic mass and biopsy consistent with well-differentiated pancreatic neuroendocrine tumor (PNET). No metastatic lesions were identified elsewhere. Due to the patient's frail status, the decision was made to have less invasive EUS-guided radiofrequency ablation (RFA). Thirteen treatments were administered, using 10 watts of radiofrequency energy. Post-ablation, the patient exhibited improvement in his mental state and resolution of hypoglycemia. On six months follow up MRI of the abdomen revealed pancreatic atrophy; pancreatic mass noted to be 1.1 cm. The patient remained free of hypoglycemia. Due to persistence of pancreatic mass, he had repeat RFA for the residual pancreatic tumor, with plans to continue MRI surveillance every six months. Discussion: Insulinomas are rare functional neuroendocrine tumors with hyper insulinemic hypoglycemia. The diagnosis of insulinoma can be difficult with most cases being diagnosed 12-18 months after the onset of symptoms. Usual age of presentation is in the middle age with rare occurrence in the elderly that can mimic delirium due to neuroglycopenia which is often missed. After the biochemical diagnosis and localization, surgical resection is the standard curative treatment for insulinoma. Elderly patients often present with higher surgical risk due to comorbidities needing minimally invasive therapeutic option such as RFA which offers advantages such as shorter recovery times, repeatability if needed and prolonged remission. Conclusion: Insulinoma should be considered as potential etiology in elderly patients with delirium. RFA is an emerging novel therapy that can be valuable in the treatment of these functional PNET in elderly, offering a safer alternative while maintaining long term therapeutic efficacy. Presentation: Saturday, July 12, 2025