BRAF mutation detection in indeterminate thyroid cytology specimens1. Issue 4 (7th August 2012)

• Record Type: Journal Article
• Authors: Ohori, N. Paul; Singhal, Rashi; Nikiforova, Marina N.; Yip, Linwah; Schoedel, Karen E.; Coyne, Christopher; McCoy, Kelly L.; LeBeau, Shane O.; Hodak, Steven P.; Carty, Sally E.; Nikiforov, Yuri E.
• Is Part Of: Cancer cytopathology. Volume 121:Issue 4(2013:Apr.)
• Page Start: 197
• Page End: 205
• Publication Date: 2012-08-07
• Subjects: Cancer -- Cytopathology -- Periodicals; Pathology, Cellular -- Periodicals; Cytology -- Technique -- Periodicals; 611.01815
• DOI: 10.1002/cncy.21229
• Languages: English
• ISSNs: 1934-662X

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <sec id="abs1-1" sec-type="section"> <title>BACKGROUND:</title> <p> <italic>BRAF</italic> mutations are highly specific for papillary thyroid carcinoma (PTC) and many cytology specimens with <italic>BRAF</italic> mutations are expected to demonstrate cytologic features typical of PTC. However, indeterminate thyroid cytology cases are inevitable and understanding the significance of the <italic>BRAF</italic> mutation within the context of the Bethesda System for Reporting Thyroid Cytopathology would be valuable.</p> </sec> <sec id="abs1-2" sec-type="section"> <title>METHODS:</title> <p>Thyroid cytology cases submitted for conventional cytomorphologic evaluation and <italic>BRAF</italic> mutational analyses were selected from the authors' cytopathology files from April 2007 to October 2011. From this group, the diagnostic usefulness of <italic>BRAF</italic> mutations in indeterminate and malignant cases was assessed and analyses of cytologic and histopathologic features associated with the mutations in this gene were performed.</p> </sec> <sec id="abs1-3" sec-type="section"> <title>RESULTS:</title> <p>A total of 131 cases with a <italic>BRAF</italic> mutation were identified. Of these, 119 underwent surgical pathology resection follow‐up and demonstrated PTC. Approximately 75% of the cases were cytologically diagnosed as being positive for malignancy and these cases were associated with both the classic and tall cell variants of PTC at the time of resection, a greater likelihood of extrathyroidal extension, and the V600E type of <italic>BRAF</italic> mutation. In contrast, <italic>BRAF</italic>‐mutated cases with diagnoses of atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) and follicular neoplasm/suspicious for follicular neoplasm were found to be more strongly associated with the follicular variant of PTC, a K601E <italic>BRAF</italic> mutation, and a lower likelihood of extrathyroidal extension. However, a subset of AUS/FLUS cases with the V600E <italic>BRAF</italic> mutation appeared to represent sampling variability of the classic or tall cell variants of PTC.</p> </sec> <sec id="abs1-4" sec-type="section"> <title>CONCLUSIONS:</title> <p>Bethesda thyroid diagnoses in the setting of a <italic>BRAF</italic> mutation reflect differences in PTC subtypes, the nature of cytology specimens, and molecular characteristics. Cancer (Cancer Cytopathol) 2013;121:197–205. © 2012 American Cancer Society.</p> </sec> </abstract>