The occurrence in a neonate of a pancreatic adenoma with nesidioblastosis in the tumor.

A newborn with persistent hypoglycemia and fixed insulin secretion unresponsive to medical management underwent 80% pancreatectomy. A 1-cm. nonencapsulated islet-cell adenoma near the tail of the pancreas was identified histologically. Islet-cell granules stained with indirect aldehyde fuchsin. Throughout the tumor, areas of nesidioblastosis were identified. The persistence of this embryologic process suggests a basic mechanism for the adenoma formation.