The focal form of persistent hyperinsulinemic hypoglycemia of infancy: morphological and molecular studies show structural and functional differences with insulinoma. Diabetes

Persistent hyperinsulinemic hypoglycemia ofinfancy (PHHI) is a disorder characterized byunregulated insulin release, leading to profoundhypoglycemia with a major risk of brain damage if not recognized early. The occurrence of PHHI is low in the Western world (~1/50,000 live births), but it can be as high as 1/2,500 live births in communities with high consanguinity. PHHI may be differentiated from the other causes of neona-tal hypoglycemia by demonstrating the persistence of an inappropriate serum insulin level, irrespective of blood glu-cose concentration, associated with a hypoketosis and a spectacular response to glucagon (1). In most cases and particularly those with severe hyper-insulinemic hypoglycemia of neonatal onset, medical ther-apy is not effective and, thus, surgery is mandatory to pre-vent permanent brain damage. Histological analyses of the resected pancreatic specimens have revealed that the dis-ease does not correspond to a single pathological entit