title: Significance of Subcategory Atypia of Undetermined Significance/Follicular Lesion of Undetermined Significance Showing Both Cytologic and Architectural Atypia in Thyroid Aspiration Cytology.
abstract: OBJECTIVE
  The Bethesda System for Reporting Thyroid Cytopathology is now widely used as the standard reporting system for fine-needle aspiration cytology (FNAC). Recently, several studies have attempted to subcategorize the atypia of undetermined significance (AUS)/follicular lesion of undetermined significance (FLUS) category. We aimed to analyze the significance of a subcategory of AUS/FLUS showing both cytologic and architectural atypia (AUS/FLUS-C&amp;A).
  
  
  METHODS
  From April 2011 to May 2014, 18,091 patients underwent FNAC at Samsung Medical Center. For those patients we analyzed the clinical significance of the subcategory AUS/FLUS-C&amp;A.
  
  
  RESULTS
  One hundred and sixty-three patients were diagnosed as AUS/FLUS-C&amp;A. Of 71 cases with subsequent histologic confirmation, 47 (66.2%) were diagnosed with papillary thyroid carcinoma (PTC). Of the 47 PTC cases, 32 (68.1%) were follicular variant-PTC. A significant difference in the PTC rate (58.3 vs. 82.6%) and PTC size (average: 1.8 and 0.9 cm) was noted between circumscribed lesions and infiltrative lesions on ultrasonography.
  
  
  CONCLUSIONS
  We demonstrated that the subcategory of AUS/FLUS-C&amp;A has considerable clinical implications and one should be aware of the cytological and ultrasonographic features.
authors.affiliation: Department of Pathology and Translational Genomics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Yoon Yang
authors.initials: YY
authors.lastname: Jung
authors.forename: Sejin
authors.initials: S
authors.lastname: Jung
authors.forename: Hyun-Woo
authors.initials: HW
authors.lastname: Lee
authors.forename: Young Lyun
authors.initials: YL
authors.lastname: Oh
mesh_terms: D018263:Adenocarcinoma, Follicular / Q000145:classification / Q000000981:diagnostic imaging / Q000235:genetics / Q000473:pathology*; D014408:Biomarkers, Tumor / Q000235:genetics; D044963:Biopsy, Fine-Needle; D002277:Carcinoma / Q000145:classification / Q000000981:diagnostic imaging / Q000235:genetics / Q000473:pathology*; D002291:Carcinoma, Papillary; D004252:DNA Mutational Analysis; D006801:Humans; D009154:Mutation; D011237:Predictive Value of Tests; D011379:Prognosis; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics; D056910:Republic of Korea; D009626:Terminology as Topic; D000077273:Thyroid Cancer, Papillary; D013961:Thyroid Gland / Q000000981:diagnostic imaging / Q000473:pathology*; D013964:Thyroid Neoplasms / Q000145:classification / Q000000981:diagnostic imaging / Q000235:genetics / Q000473:pathology*; D047368:Tumor Burden; D014463:Ultrasonography
chemical_list: D014408:Biomarkers, Tumor; C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf