Adult nesidiodysplasia

Area of Science:

• Gastroenterology and Endocrinology
• Surgical Pathology
• Cell Biology

Background:

• Investigated subtotal pancreatectomy specimens from adults with hyperinsulinemic hypoglycemia and watery diarrhea syndrome, originally diagnosed as nesidioblastosis.
• Compared these with control pancreata to identify structural differences related to endocrine dysfunction.

Observation:

• No significant difference in total endocrine cell mass between patient and control pancreata.
• Identified morphological variations in islets and islet cells in patients, including larger islets and cells with bizarre nuclei.
• Demonstrated similar ratios of insulin, glucagon, and somatostatin immunoreactivity in both groups.

Findings:

• Hyperinsulinemic hypoglycemia was not linked to quantitative endocrine cell abnormalities, maldistribution, or lack of proximity between insulin and somatostatin cells.
• Watery diarrhea syndrome showed abundant vasoactive intestinal peptide (VIP) immunoreactive cells admixed with exocrine components, suggesting ectopic expression.
• Nesidioblastosis features were present in control pancreata, indicating it is not the sole structural basis for these endocrine dysfunctions.

Implications:

• Suggests unknown derangements in insulin secretion, release, or degradation may cause hyperinsulinemic hypoglycemia.
• Highlights VIP-producing cells' potential ectopic functional expression in the pancreas in watery diarrhea syndrome.
• Challenges the view of nesidioblastosis as the direct structural cause of these adult endocrine dysfunctions.