title: Malignancy rate associated with Bethesda category III (AUS/FLUS) with and without repeat fine needle aspiration biopsy.
abstract: BACKGROUND
  Selection of nodules for surgery diagnosed as Bethesda category III [atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) category] is important. It was aimed to define the malignancy rates associated with and without repeat fine needle aspiration biopsy (FNAB) and to define the contribution of repeat FNAB to triage to surgery or observation in nodules with AUS/FLUS FNAB.
  
  
  METHODS
  The records of all patients with nodules who underwent FNAB and classified by Bethesda reporting system as AUS/FLUS at their institution were reviewed. Malignancy rates for patients with AUS/FLUS FNAB with and without repeat FNAB were calculated.
  
  
  RESULTS
  Of the 582 patients who were classified as AUS/FLUS on initial FNAB, 179 underwent surgery with an associated malignancy rate of 22.9% (upper boundary). Risk of malignancy among all patients with AUS/FLUS nodules was 7% (lower boundary). The upper and lower boundaries of the malignancy rates with and without repeat FNAB were 38.6% and 15.6% for resected patients, and 13% and 4.6% for all patients, respectively. Reclassification rate with repeat FNAB was 56%.
  
  
  CONCLUSIONS
  The findings showed that repeat FNAB for initial AUS/FLUS category was associated with a significantly increased malignancy rate compared with those without repeat FNAB. Repeat FNAB could help selection of patients with AUS/FLUS to triage to surgery. Therefore, repeat FNAB for nodules with AUS/FLUS on initial FNAB was suggested.
authors.affiliation: Department of General Surgery, Ondokuz Mayis University School of Medicine, Samsun, Turkey.
authors.forename: Bekir
authors.initials: B
authors.lastname: Kuru
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, Ondokuz Mayis University School of Medicine, Samsun, Turkey.
authors.forename: Aysegul
authors.initials: A
authors.lastname: Atmaca
authors.affiliation: Department of Pathology, Ondokuz Mayis University School of Medicine, Samsun, Turkey.
authors.forename: Mehmet
authors.initials: M
authors.lastname: Kefeli
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044963:Biopsy, Fine-Needle; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D017410:Practice Guidelines as Topic; D011237:Predictive Value of Tests; D016606:Thyroid Nodule / Q000145:classification / Q000473:pathology* / Q000601:surgery
keywords: Bethesda category III; atypia of undetermined significance; malignancy rates for AUS/FLUS; repeat FNAB for initial AUS/FLUS category