Patient selection: hypoglycemia with elevated serum or plasma insulin concentration
Major criteria (seen in all cases):
(1) exclusion of insulinoma
(2) absence of proliferative activity in endocrine cells (presumably in the pancreas)
(3) islets show a normal spatial distribution of the various islet cell types
(4) beta-cells have an abundant clear cytoplasm and an enlarged, hyperchromatic nucleus
where:
• Exclusion of factitious insulin administration could be added to the first major criterion.
Minor criteria (seen in some but not all cases):
(1) macronucleoli within beta cells
(2) islets with a lobulated structure or irregular shape
(3) increased number of islets
(4) enlargement of islets
The authors estimate that diffuse nesidioblastosis is present in about 4% of patients with PHH.
