title: Variability in the atypia of undetermined significance/follicular lesion of undetermined significance diagnosis in the Bethesda System for Reporting Thyroid Cytopathology: sources and recommendations.
abstract: OBJECTIVE
  Of the 6 categories in the Bethesda System for Reporting Thyroid Cytopathology (BSRTC), the atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) category has received the most attention. The objectives of this study were to review the use of the AUS/FLUS category in recent studies, to search for likely sources of the variability in its use, and to address possible methods for improvement.
  
  
  METHODS
  A PubMed search was performed to retrieve peer-reviewed articles that have comprehensively detailed the incidence and outcome of AUS/FLUS and other BSRTC categories. Related thyroid cytology articles on the BSRTC were also included.
  
  
  RESULTS
  Recent series that reported experiences with the BSRTC categories showed that the AUS/FLUS category exhibited a marked variability in incidence (0.7-18%) and malignant outcome (6-48%) in resection specimens. Review of the literature revealed institutional differences in technical aspects, interpretation and application of criteria, analysis of outcome data, and clinicopathologic interactions.
  
  
  CONCLUSIONS
  A heightened awareness of technical issues, diagnostic borders of AUS/FLUS, and clinical management may aid in diagnostic refinement and help avoid overuse of this category.
authors.affiliation: Department of Pathology, University of Pittsburgh Medical Center-Presbyterian, Pittsburgh, Pa., USA. ohorinp@upmc.edu
authors.forename: N Paul
authors.initials: NP
authors.lastname: Ohori
authors.forename: Karen E
authors.initials: KE
authors.lastname: Schoedel
mesh_terms: D044963:Biopsy, Fine-Needle; D002471:Cell Transformation, Neoplastic / Q000473:pathology*; D016206:Databases, Bibliographic; D003951:Diagnostic Errors; D005188:False Negative Reactions; D006801:Humans; D011379:Prognosis; D012306:Risk; D013048:Specimen Handling; D009626:Terminology as Topic; D013961:Thyroid Gland / Q000473:pathology*; D016606:Thyroid Nodule / Q000145:classification / Q000175:diagnosis* / Q000473:pathology*