title: The utility of cellient cell blocks in low-cellularity thyroid fine needle aspiration biopsies.
abstract: BACKGROUND
  Low cellularity can be problematic in thyroid fine needle aspiration (FNA) biopsies. The Cellient cell block (CB) system has been reported to improve cell recovery compared to traditional methods. Therefore, we studied the utility of Cellient CBs in the evaluation of thyroid FNAs, with an emphasis on low-cellularity specimens.
  
  
  METHODS
  ThinPrep slides were prepared from thyroid FNAs submitted in Cytolyt. After assessment using TBSRTC criteria, Cellient CBs were requested on samples with residual FNA material and an initial cytologic impression of non-diagnostic, AUS/FLUS, and on apparently benign samples with marginally adequate cellularity. The contribution of the CB findings to the final diagnosis was assessed.
  
  
  RESULTS
  965 cases of paired ThinPrep and CB sections were examined. Overall, the cell block findings resulted in a change of the initial ThinPrep impression in 15% (n = 148) of cases. The vast majority of these changed cases were initially inadequate for interpretation, and specifically, 31% (n = 123) of the non-diagnostic ThinPrep samples became diagnostic with a CB. The cell block findings contributed to a change in diagnosis in 8% (n = 23) of AUS/FLUS cases, and in less than 1% of low-cellularity benign samples.
  
  
  CONCLUSIONS
  The use of CBs in low-cellularity thyroid FNAs has not been well described. In this study, we found that the contribution of CBs in this setting varied by TBSRTC category. Specifically, the samples that benefited most were initially non-diagnostic specimens and select cases of AUS/FLUS, while low-cellularity benign samples gained very little additional information. Diagn. Cytopathol. 2016;44:737-741. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Thyroid Cytopathology Partners, 12357 Riata Trace Parkway, Bldg. 5, Suite 100, Austin, Texas.
authors.forename: Michelle
authors.initials: M
authors.lastname: Horton
authors.affiliation: Thyroid Cytopathology Partners, 12357 Riata Trace Parkway, Bldg. 5, Suite 100, Austin, Texas.
authors.forename: Laura
authors.initials: L
authors.lastname: Been
authors.affiliation: Thyroid Cytopathology Partners, 12357 Riata Trace Parkway, Bldg. 5, Suite 100, Austin, Texas.
authors.forename: Cherry
authors.initials: C
authors.lastname: Starling
authors.affiliation: Thyroid Cytopathology Partners, 12357 Riata Trace Parkway, Bldg. 5, Suite 100, Austin, Texas.
authors.forename: S Thomas
authors.initials: ST
authors.lastname: Traweek
mesh_terms: D044963:Biopsy, Fine-Needle / Q000379:methods; D016591:Histocytological Preparation Techniques / Q000379:methods*; D006801:Humans; D012680:Sensitivity and Specificity; D016606:Thyroid Nodule / Q000473:pathology*
keywords: Cellient; cell block; cytology; thin prep; thyroid