Prediction of cervical lymph node metastasis with contrast-enhanced ultrasound and association between presence of BRAF and extrathyroidal extension in papillary thyroid carcinoma.

Objective: This study aimed to evaluate the correlation between cervical lymph node metastasis (CLNM) and each of the ultrasound features, immunohistochemical factors, and B-type Raf (BRAF) mutation.

Methods: A retrospective analysis was performed on 405 patients with single papillary thyroid carcinoma (PTC) nodules, all of whom underwent preoperative sonographic examinations, including gray-scale ultrasound, color Doppler ultrasound, and contrast-enhanced ultrasound (CEUS). All PTC patients were evaluated using 14 clinical and sonographic features, eight immunohistochemical factors, and BRAF. Multivariate analyses were performed to identify the risk factors for CLNM, and an equation for CLNM was established. The diagnostic value of each modality was compared with a receiver operating characteristic (ROC) curve.

Results: Among the 405 PTC nodules removed surgically, CLNM was confirmed in 138 patients, whereas extrathyroidal extension was confirmed in 185 patients. Multivariate analyses indicated significant differences between CLNM and non-CLNM groups in three conventional ultrasound features ( < 0.05), whereas other sonographic features, eight immunohistochemical factors, and BRAF did not indicate significant differences. A ROC curve of 0.757 in the equation exhibited a significant difference compared with the solo factors ( < 0.05 for all). Hyper or isoechoic enhancement at peak time on CEUS was associated with CLNM, whereas the presence of the BRAF mutation was associated with extrathyroidal extensions although BRAF appeared to be uncorrelated with CLNM in the present study.

Conclusion: Intensity at peak time, homogeneity, and size are the three most significant features in predicting CLNM in PTC patients, and the presence of the BRAF mutation was associated with extrathyroidal extensions when PTCs showed a hyper or isoechoic enhancement at peak time in CEUS.