Neoplasms of the Neuroendocrine Pancreas An Update in the Classification, Definition, and Molecular Genetic AdvancesGuilmette, Julie M., MD; Nosé, Vania, MD, PhDAdvances in Anatomic Pathology: January 2019 - Volume 26 - Issue 1 - p 13–30 doi: 10.1097/PAP.0000000000000201 Review Articles Abstract Author InformationAuthors Article MetricsMetrics This review focuses on discussing the main modifications of the recently published 2017 WHO Classification of Neoplasms of the Neuroendocrine Pancreas (panNEN). Recent updates separate pancreatic neuroendocrine tumors into 2 broad categories: well-differentiated pancreatic neuroendocrine tumors (panNET) and poorly differentiated pancreatic neuroendocrine carcinoma (panNEC), and incorporates a new subcategory of “well-differentiated high-grade NET (G3)” to the well-differentiated NET category. This new classification algorithm aims to improve the prediction of clinical outcomes and survival and help clinicians select better therapeutic strategies for patient care and management. In addition, these neuroendocrine neoplasms are capable of producing large quantity of hormones leading to clinical hormone hypersecretion syndromes. These functioning tumors include, insulinomas, glucagonomas, somatostatinomas, gastrinomas, VIPomas, serotonin-producing tumors, and ACTH-producing tumors. Although most panNENs arise as sporadic diseases, a subset of these heterogeneous tumors present as parts on inherited genetic syndromes, such as multiple endocrine neoplasia type 1, von Hippel-Lindau, neurofibromatosis type 1, tuberous sclerosis, and glucagon cell hyperplasia and neoplasia syndromes. Characteristic clinical and morphologic findings for certain functioning and syndromic panNENs should alert both pathologists and clinicians as appropriate patient management and possible genetic counseling may be necessary. Departments of Pathology, Massachusetts General Hospital, Boston, MA The authors have no conflicts of interest to disclose. Reprints: Vania Nosé, MD, PhD, Department of Pathology, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114 (e-mail: firstname.lastname@example.org).All figures can be viewed online in color at www.anatomicpathology.com. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.