title: Reproducibility of atypia of undetermined significance/follicular lesion of undetermined significance category using the bethesda system for reporting thyroid cytology when reviewing slides from different institutions: A study of interobserver variability among cytopathologists.
abstract: BACKGROUND
  The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) offers a six-tiered diagnostic scheme for thyroid Fine Needle Aspiration (FNA): Benign, Atypia of Undetermined Significance/Follicular Lesion of Undetermined Significance (AUS/FLUS), suspicious for follicular neoplasm, suspicious for malignancy, malignant, and unsatisfactory with an aim to standardize diagnostic criteria. Reported rate of AUS/FLUS category in the literature has varied from 3% to 20.5%.
  
  
  METHODS
  The aim of this study was to assess interobserver variability among cytopathologists to assess reproducibility of the AUS/FLUS category. Seven cytopathologists brought FNA cases (a mixture of atypical and non-atypical FNA diagnosis) diagnosed using TBSRTC from their respective institutions which were reviewed and diagnosed by the participants. The analysis assessed interobserver variability among 7 cytopathologists and determined characteristics on the slides which were associated with concordance to the institutional diagnosis.
  
  
  RESULTS
  Seventy eight of 125 (62.4%) benign cases were classified as benign by the reviewers and 26 (21%) were called AUS/FLUS on review. A third of the AUS/FLUS cases were called benign on review and 28.2% were classified as suspicious for neoplasia/malignancy. Roughly a third each of the suspicious for follicular neoplasm/suspicious for malignancy cases were classified as AUS/FLUS.
  
  
  CONCLUSIONS
  When pathologists from different institutions shared their slides, concordance was high for specimens with adequate cellularity and those that were clearly benign but thresholds varied for the other indeterminate categories. Most definite categorization of the AUS/FLUS category was seen on review. Diagn. Cytopathol. 2017;45:399-405. © 2017 Wiley Periodicals, Inc.
authors.affiliation: Pathology, Baylor College of Medicine.
authors.forename: Vijayalakshmi
authors.identifier: http://orcid.org/0000-0002-2407-3269
authors.initials: V
authors.lastname: Padmanabhan
authors.affiliation: Pathology, University of Colorado Hospital.
authors.forename: Carrie B
authors.initials: CB
authors.lastname: Marshall
authors.affiliation: Pathology, Loyola University.
authors.forename: Guliz
authors.initials: G
authors.lastname: Akdas Barkan
authors.affiliation: PeaceHealth Laboratories.
authors.forename: Mohiedean
authors.initials: M
authors.lastname: Ghofrani
authors.affiliation: North Shore/LIJ Health System.
authors.forename: Alice
authors.initials: A
authors.lastname: Laser
authors.affiliation: Pathology, Mayo Clinic.
authors.forename: Idris
authors.initials: I
authors.lastname: Tolgay Ocal
authors.affiliation: Anatomic Pathology, Cleveland Clinic.
authors.forename: Charles
authors.initials: C
authors.lastname: David Sturgis
authors.affiliation: Biostatistics, Senior Biostatistician, College of American Pathologists.
authors.forename: Rhona
authors.initials: R
authors.lastname: Souers
authors.affiliation: Pathology, University of Wisconsin.
authors.forename: Daniel F I
authors.initials: DF
authors.lastname: Kurtycz
mesh_terms: D018263:Adenocarcinoma, Follicular / Q000175:diagnosis* / Q000473:pathology; D044963:Biopsy, Fine-Needle; D002277:Carcinoma / Q000175:diagnosis* / Q000473:pathology; D002291:Carcinoma, Papillary; D003937:Diagnosis, Differential; D006651:Histocytochemistry / Q000706:statistics & numerical data*; D006801:Humans; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D009369:Neoplasms / Q000175:diagnosis* / Q000473:pathology; D015588:Observer Variation; D010338:Pathology, Clinical; D015203:Reproducibility of Results; D000077273:Thyroid Cancer, Papillary; D013961:Thyroid Gland / Q000473:pathology; D013964:Thyroid Neoplasms / Q000175:diagnosis* / Q000473:pathology; D016606:Thyroid Nodule / Q000175:diagnosis* / Q000473:pathology; D000078329:Workforce
keywords: atypical; cytology; interobserver; the Bethesda system; thyroid; variability