Prevalence of BRAF(V600E) Mutation in Follicular Variant of Papillary Thyroid Carcinoma and Non-Invasive Follicular Tumor with Papillary-Like Nuclear Features (NIFTP) in a BRAF(V600E) Prevalent Area

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.