title: Young investigator challenge: Atypia of undetermined significance in thyroid FNA: Standardized terminology without standardized management--a closer look at repeat FNA and quality measures.
abstract: BACKGROUND
  The Bethesda system (TBS) for the reporting of thyroid cytopathology established the category of atypia of undetermined significance (AUS) with a 7% target rate and a 5% to 15% implied malignancy risk. Recent literature has reported a broad range of AUS rates, subsequent malignancy rates, and discrepant results from repeat fine-needle aspiration (FNA) versus surgical follow-up. Therefore, this study examined AUS data from the Hofstra North Shore-LIJ School of Medicine to determine the best clinical follow-up.
  
  
  METHODS
  Thyroid aspirates interpreted as AUS in 2012-2014 at the Hofstra North Shore-LIJ School of Medicine were collected. Repeat FNA and surgical follow-up data were tabulated to establish AUS, secondary AUS (diagnosed upon repeat FNA follow-up of a primary FNA AUS diagnosis), atypia of undetermined significance/malignancy (AUS:M) ratios (according to the TBS categories), and malignancy rates for AUS.
  
  
  RESULTS
  The AUS rate was 8.5% (976/11,481), and there was follow-up data for 545 cases. The AUS:M ratio was 2.0. Repeat FNA was performed for 281 cases; 57 proceeded to surgical intervention. Repeat FNA reclassified 71.17% of the cases. The malignancy rates for AUS cases proceeding directly to surgery and for those receiving a surgical intervention after a repeat AUS diagnosis were 33.33% and 43.75%, respectively.
  
  
  CONCLUSIONS
  Repeat FNA resulted in definitive diagnostic reclassification for 67.61% of primary AUS cases and reduced the number of patients triaged to surgery, with 56.58% of the cases recategorized as benign. Cases undergoing surgery after repeat AUS had a higher malignancy rate than those going straight to surgery, and this emphasizes the value of repeat FNA in selecting surgical candidates. In addition, this study highlights the utility of AUS rate monitoring as a quality measure that has contributed to the ability of the Hofstra North Shore-LIJ School of Medicine to adhere closely to TBS recommendations.
authors.affiliation: Department of Pathology, Hofstra North Shore-LIJ School of Medicine, Lake Success, New York.
authors.forename: Tamar C
authors.initials: TC
authors.lastname: Brandler
authors.affiliation: Department of Pathology, Hofstra North Shore-LIJ School of Medicine, Lake Success, New York.
authors.forename: Mohamed S
authors.initials: MS
authors.lastname: Aziz
authors.affiliation: Department of Pathology, Hofstra North Shore-LIJ School of Medicine, Lake Success, New York.
authors.forename: Constantinos
authors.initials: C
authors.lastname: Coutsouvelis
authors.affiliation: Department of Biostatistics, Hofstra North Shore-LIJ School of Medicine, Lake Success, New York.
authors.forename: Lisa
authors.initials: L
authors.lastname: Rosen
authors.affiliation: Department of Pathology, Hofstra North Shore-LIJ School of Medicine, Lake Success, New York.
authors.forename: Oana C
authors.initials: OC
authors.lastname: Rafael
authors.affiliation: Department of Pathology, Hofstra North Shore-LIJ School of Medicine, Lake Success, New York.
authors.forename: Fabiola
authors.initials: F
authors.lastname: Souza
authors.affiliation: Department of Pathology, Hofstra North Shore-LIJ School of Medicine, Lake Success, New York.
authors.forename: Fatima-Zahra
authors.initials: FZ
authors.lastname: Jelloul
authors.affiliation: Department of Pathology, Hofstra North Shore-LIJ School of Medicine, Lake Success, New York.
authors.forename: Melissa A
authors.initials: MA
authors.lastname: Klein
mesh_terms: D018263:Adenocarcinoma, Follicular / Q000175:diagnosis / Q000473:pathology*; D044963:Biopsy, Fine-Needle / Q000379:methods / Q000706:statistics & numerical data; D015331:Cohort Studies; D003937:Diagnosis, Differential; D019468:Disease Management; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D011786:Quality Control; D012108:Research Personnel; D012189:Retrospective Studies; D009626:Terminology as Topic; D013961:Thyroid Gland / Q000473:pathology* / Q000601:surgery*; D013964:Thyroid Neoplasms / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery*; D013965:Thyroidectomy / Q000379:methods
keywords: atypia of undetermined significance (AUS); quality; repeat fine-needle aspiration (FNA); thyroid