Hyperinsulinemic hypoglycemia in children is most commonly due to congenital hyperinsulinism resulting from defects in genes that regulate insulin secretion; there have been very few reports on pediatric acquired insulinomas.2) Gupta et al. alidentified only 33 cases involving a child or adolescent with an insulinoma in a review of the relevant literature from the past 50 years.3) For our patient, the sudden onset of symptoms without a history of neonatal hypoglycemia was consistent with an acquired process rather than a congenital one. The gene discussed is INS; the disease is hyperinsulinism.