Pancreatic nesidioblastosis in adults. Report of a patient with hyperinsulinemic hypoglycemia.

Hyperinsulinemic hypoglycemia in neonates occurs most commonly secondary to nesidioblastosis, a persistence of fetal development of the endocrine cells of the pancreas. In adults, hyperinsulinemic hypoglycemia is usually due to insulinoma or beta-cell hyperplasia. Nesidioblastosis arising in adults has only recently been reported. An adult patient with nesidioblastosis has been described. The light and electron microscopic films of this entity are shown in detail, and the embryology and treatment are discussed. Further understanding of this newly described disease entity will require research on factors that regulate the differentiation of beta cells of the pancreas.