Focal hyperinsulinism in ectopic pancreatic tissue: preoperative localization and curative resection

Ectopic pancreas (EP) is pancreatic tissue located outside the native pancreas. Most cases are asymptomatic and identified incidentally. Only a few cases of hyperinsulinism (HI) arising from EP have been reported. We describe an infant who had neonatal hypoglycemia which was not shown to be resolved and later presented at 5 months of age with recurrent abnormal limb movements associated with severe hypoglycemia. Following failure of diazoxide therapy, genetic testing identified a paternally inherited pathogenic variant in ABCC8. Preoperative fluorine-18-L-dihydroxyphenylalanine positron emission tomography/computed tomography (¹⁸F-DOPA PET/CT) revealed a focal area of uptake in the distal duodenum/proximal jejunum consistent with ectopic pancreatic tissue. Surgical resection of this lesion resulted in complete resolution of hypoglycemia while preserving the native pancreas. We review previously reported cases of congenital HI arising in ectopic pancreatic tissue, highlighting the novelty of preoperative ¹⁸F-DOPA PET/CT localization that enabled curative resection during the initial surgery for our patient.