title: False-positive FNA due to highly sensitive BRAF assay.
abstract: OBJECTIVE
  False-positive BRAF analysis on fine-needle aspiration (FNA) has rarely been reported in the literature but may become more common with the advent of assays that can detect the BRAF V600E mutation in only 2% of otherwise wild-type thyroid cells. We present the case of an indeterminate BRAF-positive FNA that showed no evidence of cancer on final surgical pathology.
  
  
  METHODS
  Case report and literature review.
  
  
  RESULTS
  An 87-year-old female with an indeterminate 1.7-cm nodule but BRAF-positive cytology underwent thyroid lobectomy. Final pathology revealed a benign adenomatoid nodule. An area rich in tumor cells from the nodule was identified, labeled, and microdissected for molecular testing, which demonstrated only wild-type BRAF, at the analytical limit of the assay.
  
  
  CONCLUSIONS
  Increasingly sensitive BRAF assays using dual-priming oligonucleotide-based multiplex polymerase chain reaction analysis can detect the BRAF V600E mutation when present in only 2% of a population of wild-type cells. This increases the risk of false-positive results, particularly in cases of indeterminate FNA. Clinicians must caution patients in these circumstances that BRAF molecular testing may not have a 100% positive predictive value.
authors.affiliation: Department of Otolaryngology, Head, and Neck Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania.
authors.forename: Monica M
authors.initials: MM
authors.lastname: DiLorenzo
authors.affiliation: Department of Endocrinology, Thomas Jefferson University, Philadelphia, Pennsylvania.
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Miller
authors.affiliation: Department of Pathology, Thomas Jefferson University, Philadelphia, Pennsylvania.
authors.forename: Madalina
authors.initials: M
authors.lastname: Tuluc
authors.affiliation: Department of Pathology, Thomas Jefferson University, Philadelphia, Pennsylvania.
authors.forename: Zi-Xuan
authors.initials: ZX
authors.lastname: Wang
authors.affiliation: Department of Endocrinology, Thomas Jefferson University, Philadelphia, Pennsylvania.
authors.forename: Vincent W
authors.initials: VW
authors.lastname: Savarese
authors.affiliation: Department of Otolaryngology, Head, and Neck Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania.
authors.forename: Edmund A
authors.initials: EA
authors.lastname: Pribitkin