Is Follow-up BRAFV600E Mutation Analysis Helpful in the Differential Diagnosis of Thyroid Nodules with Negative Results on Initial Analysis?

Background We evaluated the usefulness of follow-up BRAFV600E mutation analysis using ultrasonography-guided fine-needle aspiration (US-FNA) in diagnosis of thyroid nodules showing negative BRAFV600E mutation on prior analysis. Methodology/Principal Finding A total of 49 patients (men: 6, women: 43, mean age: 50.4 years) with 49 thyroid nodules were included. Patients had undergone initial and follow-up US-FNA and subsequent BRAFV600E mutation analysis from US-FNA aspirates. All patients had negative results on initial BRAFV600E mutation analysis. Clinicopathologic findings, US assessment, and BRAFV600E mutation results were analyzed according to the final pathology. Of the 49 nodules, 12 (24.5%) were malignant and 37 (75.5%) were benign. Seven (58.3%) of the 12 malignant nodules were positive for BRAFV600E mutation on follow-up, all showing suspicious US features. Initial US-FNA cytology of the 7 nodules were non-diagnostic (n = 2), benign (n = 2), or atypia (n = 3), while follow-up were benign (n = 1), indeterminate (n = 1), suspicious for malignancy (n = 4), and malignancy (n = 1). Conclusions/Significance Follow-up BRAFV600E mutation analysis may be helpful in the diagnosis of selected thyroid nodules negative for BRAFV600E mutation on initial analysis, which are assessed as suspicious malignant on US, diagnosed as non-diagnostic, benign or atypia on follow-up US-FNA.