Nesidioblastosis and intermediate cells in the pancreas of patients with hyperinsulinemic hypoglycemia.

The pancreases of three patients with hyperinsulinemic hypoglycemia were studied: one of these patients was a child born to a diabetic mother, the other two were adults with insulinomas. All the patients had nesidioblastosis, namely the presence of a number of pancreatic endocrine cells spread throughout the exocrine tissue singly or clustered in small groups. In the hypoglycemic child the endocrine cells scattered in the acinar tissue were mostly A cells, whereas in the patients with insulinomas both A and B cells were found with a similar frequency. Intermediate cells (acinar-islet cells) were found in all the cases. These findings suggest that nesidioblastosis and the de novo formation of intermediate cells are associated phenomena. Possible mechanisms for the genesis of the islet cell types spread throughout the exocrine parenchyma and of the intermediate cells are discussed and their possible clinical implications are suggested.