301 Morphometric Analysis of Pancreatic Islet Cells: Two Cases of Nesidioblastosis Following Sleeve Gastrectomy

Abstract

Introduction: Nesidioblastosis is a rare cause of non-insulinoma pancreatogenous hypoglycemia most commonly found in children. Idiopathic adult-onset cases have been described in the literature, but most recently adult onset nesidioblastosis has been described following gastric bypass surgery. At our institution, we have two such cases. Method(s): Morphometric analysis of these two cases and two age-and gender-matched controls was performed. H&E sections were scanned using a whole slide scanner, and the outlines of the islets were traced using manual inspection. Refinement to the islet surface areas was performed using image-processing techniques. Analysis of islet area and ratio of endocrine to exocrine surface area was performed. Result(s): The mean islet area of the first nesidioblastosis case was 2.0777 x 104, while the normal control had a mean area of 8.6457 x 103. The second case had a mean islet area of 1.7323 x 104, and the normal control had a mean islet area of 8.7521 x 103. Thus, on average, the ratio of endocrine to exocrine area was observed to be larger by 3-to 15-fold in nesidioblastosis. A trend towards alteration in nuclear size and density was also observed which would require further study in a larger cohort. Conclusion(s): In summary, using morphometric analysis, hyperplasia of the islet cells is observed to occur in a subset of adult individuals after sleeve gastrectomy. This suggests possible alterations in growth hormone production, as reported in pediatric nesidioblastosis, requiring further study in adults post gastric bypass surgery subjects.