Nesidioblastosis: An autopsy case The morphoiogical abnormalities of the endocrine pancreas that underlie Persistent Neonatal Hyperinsulinemic Hypoglycemia (PNHH) and are included under the heading " nesidioblastosis" appear to be heterogeneous. Nesidioblastosis is the process of differentiation of pancreatic islets from ductular epithelium . The clinicopathologic features of an infant who presented with hyperinsulinemic hypoglycemia, died at the age of 18 days and had nesidioblastosis diagnosed by autopsy are presented and histopathological diagnostic difficulties are discussed together with the literature.