Concurrent Adult-Onset Diffuse β-Cell Nesidioblastosis and Pancreatic Neuroendocrine Tumor: A Case Report and Review of the Literature

Abstract

Nesidioblastosis is an uncommon cause of organic persistent hyperinsulinemic hypoglycemia in adults. We report a case of adult-onset diffuse β-cell nesidioblastosis in a 49-year-old woman who was status-post Roux-en-Y gastric bypass and distal pancreatectomy for a well-differentiated pancreatic neuroendocrine tumor. While the neuroendocrine tumor was suspected to be an insulinoma, persistent hypoglycemia postoperatively suggested either incomplete resection or a second pancreatic neoplasm. Completion pancreatectomy revealed islet β-cell hyperplasia and nuclear pleomorphism consistent with β-cell nesidioblastosis. The patient’s blood glucose levels normalized after completion pancreatectomy. While β-cell nesidioblastosis and insulinomas can coexist in the same patient, pathologists should be aware of β-cell nesidioblastosis as a potential cause for hyperinsulinemic hypoglycemia and should exclude it in patients who have not shown definitive clinical response after surgical excision of a pancreatic neuroendocrine tumor.

Nesidioblastosis and Insulinoma: A Rare Coexistence and a Therapeutic Challenge

“…The association of these two entities is a rare clinical finding. To the best of our knowledge, the association between nesidioblastosis and neoplastic diseases of the endocrine pancreas has been described in just a few cases (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21). The peculiarity of our case is that the diagnoses of nesidioblastosis and insulinoma were not concomitant.…”

Case report: composite pancreatic intraductal papillary mucinous neoplasm and neuroendocrine tumor: a new mixed neuroendocrine-non-neuroendocrine neoplasm?

“…Another point that needs to be kept in mind is the differential diagnosis between NET and neuroendocrine hyperplasia. The latter has a series of major and minor critieria and its diagnosis, especially diffuse hyperplasia, might need near total pancreatectomy [ 43 – 45 ].…”

Diffuse, Adult-Onset Nesidioblastosis/Non-Insulinoma Pancreatogenous Hypoglycemia Syndrome (NIPHS): Review of the Literature of a Rare Cause of Hyperinsulinemic Hypoglycemia

“…Exclusion of an insulinoma by means of macroscopic, microscopic, and immunohistochemical evaluation of the tissue is the last major criterion to diagnose diffuse, adult-onset nesidioblastosis. From our point of view, this is problematic because many patients have been reported that suffered from pathologically detectable insulinoma and concomitant islet cell hyperplasia/nesidioblastosis (also termed “background nesidioblastosis”) [ 16 , 58 , 75 , 109 , 231 , 235 , 283 , 285 , 286 , 316 , 317 ]. One patient was even reported to have an insulinoma relapse, which was possibly related to the coexistence of islet cell hyperplasia/nesidioblastosis [ 231 ].…”