Multiple Endocrine Neoplasia Type 1 Presenting as Hypoglycemia due to Insulinoma

Multiple endocrine neoplasia (MEN) mutation is an autosomal dominant disorder characterized by the occurrence of parathyroid, pancreatic islet, and anterior pituitary tumors. The incidence of insulinoma in MEN is relatively uncommon, and there have been a few cases of MEN manifested with insulinoma as the first symptom in children. We experienced a 9-year-old girl having a familial MEN1 mutation. She complained of dizziness, occasional palpitation, weakness, hunger, sweating, and generalized tonic-clonic seizure that lasted for 5 minutes early in the morning. At first, she was only diagnosed with insulinoma by abdominal magnetic resonance images of a 1.3 x 1.5 cm mass in the pancreas and high insulin levels in blood of the hepatic vein, but after her father was diagnosed with MEN1. We found she had familial MEN1 mutation, and she recovered hyperinsulinemic hypoglycemia after enucleation of the mass. Therefore, the early genetic identification of MEN1 mutation is considerable for children with at least one manifestation.