ABSTRACT
BACKGROUND: BRAF V600E mutation status and prevalence of non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) has not yet been reported in Korea. The aim of this study was to investigate the significance of the BRAF V600E mutation in the follicular variant of papillary thyroid carcinoma (FVPTC) and to determine the prevalence of NIFTP in BRAF V600E mutation-prevalent Korean patients. METHODS: This study retrospectively analyzed 1,417 consecutive patients who underwent total thyroidectomy with routine prophylactic central lymph node dissection for papillary thyroid carcinoma (PTC). BRAF V600E mutation analysis was performed routinely using multiplex polymerase chain reaction by applying dual priming oligonucleotide. Clinicopathological characteristics and ultrasonographic findings were compared between BRAF V600E mutation-positive and -negative groups for FVPTC. Pathologists reviewed the pathology slides according to consensus diagnostic criteria for the encapsulated FVPTC and NIFTP. RESULTS: The prevalence of the BRAF V600E mutation in all subtypes of PTC was 61.0% (861/1,411). FVPTC presented a BRAF V600E mutation rate of 27.3%. The FVPTC patients with BRAF V600E mutation were older than those with no BRAF V600E mutation (P = 0.021). The prevalence of NIFTP was 0.18% among all PTC patients (2/1,411) and the proportion of NIFTP among FVPTC was 9.1% (2/22). CONCLUSION: The BRAF V600E mutation is prevalent in Korean patients with FVPTC in a region with high frequency of the BRAF V600E mutation and very low prevalence of NIFTP compared with that reported in western studies.