title: Neuroendocrine tumors of the luminal gastrointestinal tract.
abstract: BACKGROUND
  Neuroendocrine tumors (NETs) of the gastrointestinal tract have been recognized for more than a century. Despite histologic similarities between different sites in the tract, behavior varies between areas. All of these tumors have malignant potential, but determination of exact risk is difficult.
  
  
  OBJECTIVE
  To review the diagnosis of luminal gastrointestinal NETs, including a discussion of grading. Grading by mitotic index/activity, in conjunction with tumor size/stage, has been found to be the strongest predictor of behavior.
  
  
  METHODS
  Literature review of luminal gastrointestinal NETs was performed and the results summarized.
  
  
  CONCLUSIONS
  Our understanding of these lesions is incomplete and continues to evolve.
authors.affiliation: From the Department of Laboratory Medicine and the Li Ka Shing Knowledge Institute, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Andrea
authors.initials: A
authors.lastname: Grin
authors.forename: Catherine J
authors.initials: CJ
authors.lastname: Streutker
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism; D005770:Gastrointestinal Neoplasms / Q000175:diagnosis* / Q000378:metabolism; D041981:Gastrointestinal Tract / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D006965:Hyperplasia; D008940:Mitotic Index; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D055099:Neuroendocrine Cells / Q000378:metabolism / Q000473:pathology*; D018358:Neuroendocrine Tumors / Q000175:diagnosis* / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor