Prevalence and Diagnostic Performance of the BRAF V600E Mutation in Papillary Thyroid Carcinoma: A Cross-Sectional Study in Uruguay.

Thyroid cancer is the most common endocrine malignancy, and the detection of thyroid nodules has increased with the widespread use of ultrasound. In this context, the BRAF V600E mutation has emerged as an important molecular marker in papillary thyroid carcinoma; however, its prevalence varies geographically and local data remain limited. This study aimed to determine the prevalence of the BRAF V600E mutation in a Uruguayan population and to evaluate its potential role as a complementary diagnostic tool. A cross-sectional analytical study was conducted including 155 patients who underwent fine-needle aspiration (FNA) for thyroid nodules at Maciel Hospital between October 2020 and September 2022). Archived formalin-fixed paraffin-embedded (FFPE) tumor samples were also analyzed to increase the number of histologically confirmed cases. Detection of the BRAF V600E mutation was performed using allele-specific PCR. Clinical, ultrasonographic, cytological (Bethesda classification), and histopathological data were collected from medical records. The prevalence of the BRAF V600E mutation was 75.9% among 29 papillary thyroid carcinomas and only 4/151 benign lesions (2.6%). The assay showed a sensitivity of 73.3% (CI 55.6% - 85.8) and a specificity of 95.4% (IC 90.7% - 97.7%), with a positive predictive value of 75.9% (CI 57.9% - 87.8%) and a negative predictive value of 94.7 (CI 90.0% - 97.3%) Significant associations were observed between the mutation and Bethesda categories V-VI (p < 0.001), hypoechogenicity (p = 0.01) and malignant histopathology (p < 0.001). These findings support the use of BRAF mutation testing may serve as a complementary tool in the diagnostic assessment of thyroid nodules.