title: Histological features associated with diagnostic agreement in atypical ductal hyperplasia of the breast: illustrative cases from the B-Path study.
abstract: OBJECTIVE
  This study examined the case-specific characteristics associated with interobserver diagnostic agreement in atypical ductal hyperplasia (ADH) of the breast.
  
  
  RESULTS
  Seventy-two test set cases with a consensus diagnosis of ADH from the B-Path study were evaluated. Cases were scored for 17 histological features, which were then correlated with the participant agreement with the consensus ADH diagnosis. Participating pathologists' perceptions of case difficulty, borderline features or whether they would obtain a second opinion were also examined for associations with agreement. Of the 2070 participant interpretations of the 72 consensus ADH cases, 48% were scored by participants as difficult and 45% as borderline between two diagnoses; the presence of both of these features was significantly associated with increased agreement (P < 0.001). A second opinion would have been obtained in 80% of interpretations, and this was associated with increased agreement (P < 0.001). Diagnostic agreement ranged from 10% to 89% on a case-by-case basis. Cases with papillary lesions, cribriform architecture and obvious cytological monotony were associated with higher agreement. Lower agreement rates were associated with solid or micropapillary architecture, borderline cytological monotony, or cases without a diagnostic area that was obvious on low power.
  
  
  CONCLUSIONS
  The results of this study suggest that pathologists frequently recognize the challenge of ADH cases, with some cases being more prone to diagnostic variability. In addition, there are specific histological features associated with diagnostic agreement on ADH cases. Multiple example images from cases in this test set are provided to serve as educational illustrations of these challenges.
authors.affiliation: Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA.
authors.forename: Kimberly H
authors.initials: KH
authors.lastname: Allison
authors.affiliation: Department of Pathology, University of Washington School of Medicine, Seattle, WA, USA.
authors.forename: Mara H
authors.initials: MH
authors.lastname: Rendi
authors.affiliation: Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA.
authors.forename: Sue
authors.initials: S
authors.lastname: Peacock
authors.affiliation: Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA.
authors.forename: Tom
authors.initials: T
authors.lastname: Morgan
authors.affiliation: Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA.
authors.forename: Joann G
authors.initials: JG
authors.lastname: Elmore
authors.affiliation: Department of Pathology and University of Vermont Cancer Center, University of Vermont, Burlington, VT, USA.
authors.forename: Donald L
authors.initials: DL
authors.lastname: Weaver
mesh_terms: D001943:Breast Neoplasms / Q000175:diagnosis* / Q000473:pathology; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000175:diagnosis* / Q000473:pathology; D005260:Female; D006801:Humans; D015588:Observer Variation; D010338:Pathology, Clinical / Q000592:standards*
keywords: B-Path study; atypical ductal hyperplasia; breast pathology; diagnostic agreement; interobserver agreement