Follicular variant of papillary thyroid carcinoma with B-type Raf(V600E) showing higher frequency of suspicious sonographic features and multifocality.

BACKGROUND: The purpose of this study was to investigate the correlation between B-type Raf (BRAF) kinase mutation and clinicopathological features of follicular variant of papillary thyroid carcinoma (PTC). METHODS: Eighty-four patients with pathologically confirmed follicular variant of PTC, who underwent a preoperative BRAF(V600E) study, were analyzed. Clinicopathological parameters and ultrasonographic features were compared between the BRAF(V600E) -positive and negative groups. RESULTS: A total of 41.7% of the patients showed BRAF(V600E) . The BRAF(V600E) -positive group showed the smaller tumor size (7.3 ± 3.6 mm vs 10.7 ± 8.9 mm; p = .018) and the more frequent multifocality (25.7% vs 8.2%; p = .028). Follicular variant of PTC with BRAF(V600E) showed suspicious ultrasonographic features (88.6% vs 57.1%; p = .002) more frequently. BRAF(V600E) positivity is associated with multifocality after adjusting for age, sex, the presence of suspicious ultrasonographic features, pathological tumor size, and thyrotropin level. CONCLUSION: BRAF(V600E) was correlated with smaller tumor size and suspicious ultrasonographic features in follicular variant of PTC. BRAF(V600E) was a significant parameter for predicting multifocality of follicular variant of PTC.