title: Recent Updates on Neuroendocrine Tumors From the Gastrointestinal and Pancreatobiliary Tracts.
abstract: BACKGROUND
  -Gastrointestinal (GI) and pancreatobiliary tracts contain a variety of neuroendocrine cells that constitute a diffuse endocrine system. Neuroendocrine tumors (NETs) from these organs are heterogeneous tumors with diverse clinical behaviors. Recent improvements in the understanding of NETs from the GI and pancreatobiliary tracts have led to more-refined definitions of the clinicopathologic characteristics of these tumors. Under the 2010 World Health Organization classification scheme, NETs are classified as grade (G) 1 NETs, G2 NETs, neuroendocrine carcinomas, and mixed adenoneuroendocrine carcinomas. Histologic grades are dependent on mitotic counts and the Ki-67 labeling index. Several new issues arose after implementation of the 2010 World Health Organization classification scheme, such as issues with well-differentiated NETs with G3 Ki-67 labeling index and the evaluation of mitotic counts and Ki-67 labeling. Hereditary syndromes, including multiple endocrine neoplasia type 1 syndrome, von Hippel-Lindau syndrome, neurofibromatosis 1, and tuberous sclerosis, are related to NETs of the GI and pancreatobiliary tracts. Several prognostic markers of GI and pancreatobiliary tract NETs have been introduced, but many of them require further validation.
  
  
  OBJECTIVE
  -To understand clinicopathologic characteristics of NETs from the GI and pancreatobiliary tracts.
  
  
  METHODS
  -PubMed (US National Library of Medicine) reports were reviewed.
  
  
  CONCLUSIONS
  -In this review, we briefly summarize recent developments and issues related to NETs of the GI and pancreatobiliary tracts.
authors.forename: Joo Young
authors.initials: JY
authors.lastname: Kim
authors.affiliation: From the Department of Pathology, Korea University Anam Hospital, Korea University College of Medicine, Seoul, Korea (Dr Kim); and the Department of Pathology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea (Dr Hong).
authors.forename: Seung-Mo
authors.initials: SM
authors.lastname: Hong
mesh_terms: D001659:Biliary Tract / Q000378:metabolism / Q000473:pathology; D001661:Biliary Tract Neoplasms / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D014408:Biomarkers, Tumor / Q000378:metabolism; D018278:Carcinoma, Neuroendocrine / Q000175:diagnosis / Q000378:metabolism / Q000473:pathology; D003937:Diagnosis, Differential; D004502:Education, Medical, Continuing; D005770:Gastrointestinal Neoplasms / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D041981:Gastrointestinal Tract / Q000378:metabolism / Q000473:pathology; D006801:Humans; D008940:Mitotic Index; D018198:Mixed Tumor, Malignant / Q000175:diagnosis / Q000378:metabolism / Q000473:pathology; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D055099:Neuroendocrine Cells / Q000378:metabolism / Q000473:pathology*; D018358:Neuroendocrine Tumors / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D010179:Pancreas / Q000378:metabolism / Q000473:pathology; D010190:Pancreatic Neoplasms / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D010338:Pathology, Clinical / Q000193:education / Q000379:methods* / Q000639:trends; D017410:Practice Guidelines as Topic; D011379:Prognosis; D000078329:Workforce; D014944:World Health Organization
chemical_list: D014408:Biomarkers, Tumor