Clinical and Pathological Features and the BRAF V600E Mutation in Patients with Papillary Thyroid Carcinoma with and without Concurrent Hashimoto Thyroiditis

BACKGROUND: It has been reported that patients with papillary thyroid carcinoma (PTC) have a high incidence of background Hashimoto thyroiditis (HT); however, the linkage of HT to PTC is controversial. Recent studies have shown that the prevalence of activating point mutations in BRAFV600E is much higher (73-86%) in Korea than in Western countries (29-69%), and associated with a poor prognosis in PTC. The purpose of the present study was to investigate the frequency of the BRAFV600E mutation in PTC with and without HT, and to determine clinical and pathological features that were associated with concomitant HT and PTC. METHODS: Fine-needle aspiration slides from 101 patients with surgically confirmed PTC were studied. The DNA was extracted from the atypical cells that were scraped from slides. It was then analyzed for the BRAFV600E mutation by pyrosequencing. In addition, the presence of background HT in surgical specimens and other clinical and pathological features of the patients were characterized. RESULTS: HT was present in 37 (36.6%) of the patients. The BRAFV600E mutation was present in 27 (72.9%) of patients with HT but was present in 61 (95.3%) of patients without HT ( p#0.01). The inverse correlation of concurrent HT with the BRAFV600E mutation was significant for both males and females ( p < 0.01). The presence of background HT was not associated with tumor size, extrathyroidal invasion, lymph node (LN) metastasis, or tumor stage. The patients were younger in the group without background HT (44.1 +/- 13.2 vs. 49.8 +/- 13.9, p 1/40.05). The BRAFV600E mutation was present in 88 (87.1%) of the 101 patients with PTC. The presence of the BRAFV600E mutation was significantly associated with LN metastasis ( p < 0.02; odds ratio, 6.24; 95% confidence interval, 1.51-25.79). CONCLUSION: In Korean patients with PTC, the BRAFV600E mutation is associated with a lower frequency of background HT and a high frequency of LN metastasis.