Nesidioblastosis	

Functional hyperinsulinism (inappropriate hyperinsulinaemia in the presence of hypoglycaemia) is comparatively common in newborns but very rare in older children and in adults. It does not have a well-defined histopathological basis – the diffuse B-cell hyperplasia often referred to as nesidioblastosis is not necessarily confined to the well-demarcated islets of Langerhans, and occurs as an anatomical finding in many normal babies, and even in adults who never experience spontaneous hypoglycaemia. 
In its mildest form, functional hyperinsulinism of infants produces a transient lowering of blood glucose concentration and minimal inappropriate hyperinsulinaemia, often accompanied by slight and temporary neuroglycopenia during the first few days of life.