title: A Population-Based Analysis of Application of WHO Nomenclature in Pathology Reports of Pulmonary Neuroendocrine Tumors.
abstract: BACKGROUND
  Pulmonary neuroendocrine tumors (pNETs) are difficult to classify. We performed a population-based analysis to investigate the application of pNET nomenclature in daily pathology practice.
  
  
  METHODS
  Conclusions from pathology reports (2003-2012) describing carcinoids, (large cell) neuroendocrine carcinomas (NECs), and carcinomas with neuroendocrine features/differentiation were retrieved from the Dutch Pathology Registry by queries on location and diagnosis and screened for terminology. Cases with a nonpulmonary or unknown origin and small cell lung cancer were excluded. Diagnoses were clustered into subgroups and the retrieved terminology was compared with the 2015 World Health Organization (WHO) diagnoses. By means of an online questionnaire, interpretation of the non-WHO nomenclature retrieved from pathology reports was evaluated (by 35 physicians and 19 pathologists).
  
  
  RESULTS
  A total of 3216 unique pathology report conclusions with 55 different pNET diagnoses (n = 3052) and 20 uncertain diagnoses (n = 164) were analyzed. Non-WHO nomenclature was used in 15% of diagnoses (n = 488). Diagnoses could be clustered into carcinoids (n = 1086), NEC (n = 1316), carcinomas with neuroendocrine features/differentiation (n = 624), and unspecified pNETs (n = 26). Non-WHO nomenclature within these clusters was found for 7% of carcinoids, 20% of NECs, 13% of carcinomas with neuroendocrine features/differentiation, and 100% of unspecified pNETs and was observed more often in conclusions regarding biopsy or cytological specimens (62% and 12%) compared with resection specimens (26%). Analysis of the questionnaire results revealed that 4 of 19 diagnoses based on non-WHO nomenclature were uniformly interpreted (>50% agreement) by physicians, as were 10 of 19 diagnoses by pathologists.
  
  
  CONCLUSIONS
  In 15% of pNETs other than small cell lung cancer, a non-WHO nomenclature diagnosis was provided, more frequently on the basis of smaller specimens. The interpretation was different between physicians and pathologists. Application of uniform nomenclature among all clinicians is advocated.
authors.affiliation: Department of Pulmonary Diseases, GROW School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht, The Netherlands.
authors.forename: Jules L
authors.initials: JL
authors.lastname: Derks
authors.affiliation: Department of Pathology, Jeroen Bosch Hospital, s'-Hertogenbosch, The Netherlands.
authors.forename: Robert Jan
authors.initials: RJ
authors.lastname: van Suylen
authors.affiliation: Department of Pathology, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Erik
authors.initials: E
authors.lastname: Thunnissen
authors.affiliation: Department of Pathology, Maasstad Hospital, Rotterdam, The Netherlands; Department of Pathology, Erasmus Medical Centre, Rotterdam, The Netherlands.
authors.forename: Michael A
authors.initials: MA
authors.lastname: den Bakker
authors.affiliation: Department of Pulmonary Diseases, VU Medical Center, Amsterdam, The Netherlands; Department of Thoracic Oncology, Netherlands Cancer Institute, Amsterdam, The Netherlands.
authors.forename: Egbert F
authors.initials: EF
authors.lastname: Smit
authors.affiliation: Department of Pulmonary Diseases, University of Groningen and University Medical Centre, Groningen, The Netherlands.
authors.forename: Harry J M
authors.initials: HJ
authors.lastname: Groen
authors.affiliation: Department of Pathology, GROW School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht, The Netherlands.
authors.forename: Ernst J M
authors.initials: EJ
authors.lastname: Speel
authors.affiliation: Department of Pulmonary Diseases, GROW School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht, The Netherlands. Electronic address: a.dingemans@mumc.nl.
authors.forename: Anne-Marie C
authors.initials: AM
authors.lastname: Dingemans
mesh_terms: D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology*; D008495:Medical Oncology / Q000379:methods*; D018358:Neuroendocrine Tumors / Q000473:pathology*; D010336:Pathology / Q000379:methods*; D012189:Retrospective Studies; D011795:Surveys and Questionnaires; D009626:Terminology as Topic; D014944:World Health Organization
keywords: Carcinoids; Diagnosis; LCNEC; Nomenclature; Pulmonary neuroendocrine tumors