Diagnostic performance of combining sonographic features with BRAF^V600E mutation for differentiating benign and malignant Bethesda category Ⅲ thyroid nodules

To evaluate the diagnostic performance of combining sonographic features with BRAF^V600E mutation for differentiating benign and malignant Bethesda category Ⅲ thyroid nodules.

This retrospective cohort study included 275 patients (278 nodules) diagnosed as Bethesda category Ⅲ by ultrasound-guided fine needle aspiration cytology (US-FNAC) at First Affiliated Hospital of Army Medical University between January 2020 and December 2024, with final confirmation via surgical pathology or repeated US-FNAC. Nodules were classified as benign or malignant based on pathological results. Diagnostic efficacy of age, sex, 9 sonographic features, ACR TI -RADS score, US-FNAC nuclear morphology, and BRAF^V600E mutation was analyzed using multivariate logistic regression.

Significant differences existed in age, nodule margin, aspect ratio, maximum diameter, echogenicity, Adler blood flow grading, ACR TI-RADS classification, US-FNAC nuclear morphology, and BRAF^V600E status between benign and malignant nodules (all P<0.05). Independent risk factors for malignancy included age≤52 years (OR=7.444), BRAF^V600E mutation (OR =108.218), ground-glass nuclei (OR =5.389), and abnormal cervical lymph nodes (OR=13.351, P<0.05). The combined model demonstrated accuracy was 0.823, sensitivity was 0.863, specificity was 0.925, positive predictive value was 0.977, negative predictive value was 0.649, and AUC was 0.955.

Integration of sonographic features and BRAF^V600E mutation provides high diagnostic performance for Bethesda category Ⅲ thyroid nodules.