Ultrasound-guided fine-needle aspiration (FNA) is routinely used in the evaluation of thyroid nodules. However, it has several pitfalls, as has been noted in nondiagnostic and indeterminate cases. This study aims to investigate the value of BRAF^V600E mutation co-testing in FNA cytology.

A total of 310 patients underwent BRAF^V600E mutation co-testing in FNA cytology on thyroid nodules between June 2013 and June 2014. Of the 310 patients, 69 patients who had undergone a surgery for thyroid nodules were included in this study. The presence of the BRAF^V600E mutation was determined by allele-specific polymerase chain reaction amplification of exon 15 of the BRAF gene.

Of 69 cases, 33 (47.8%) were BRAF^V600E mutation positive. The BRAF^V600E mutation was not significantly associated with high-risk features such as tumor size, lymph node metastasis, and pathological stage. The respective diagnostic performance of FNA (P = 0.02), BRAF^V600E mutation (P = 0.03), and ultrasonographic (P = 0.00) findings was statistically significant. The sensitivity, specificity and positive predictive value of FNA was 64.9%, 83.3%, and 94.8%. The sensitivity, specificity and positive predictive value of BRAF^V600E mutation was 56.1%, 91.7%, and 96.9% and the US features was 91.2%, 91.7%, and 98.1% respectively. However, sensitivity of FNA with BRAF^V600E mutation (77.2%) was lower than FNA with US (92.9%) and combination all together (92.9%).

In this study, we found that US features were the most useful in preoperative differential diagnosis of thyroid nodules. BRAF^V600E mutation co-testing in FNA cytology was also useful for diagnosis of thyroid tumors.