Differentiation between benign and metastatic cervical lymph nodes using ultrasound

Purpose: The oral cavity is the most common site for squamous cell carcinoma, which has a distinct predilection for lymphatic spread before distant systemic metastasis. The cervical lymph node status is a very important consideration in the assessment of squamous cell carcinoma. Ultrasound is a noninvasive and inexpensive technique that can be used to differentiate between the benign and metastatic nodes. So the aim of this study was to evaluate reliability of ultrasound for such differentiation and to correlate them with histopathological finding. Materials and Methods: A total of 200 lymph nodes from 38 patients histopathologically proven for oral squamous cell carcinoma who underwent surgical neck dissection were considered. The patients underwent ultrasound examination of cervical lymph nodes prior to surgical neck dissection. The lymph nodes were differentiated into benign and metastatic based on the assessment of size, shape, shortest diameter/longest diameter (S/L ratio), margin, and internal architecture, and also the internal echo structure of the lymph nodes and histopathological findings were analyzed. Results: On correlation of ultrasonographic diagnosis with histopathological evaluation for metastatic lymph nodes, the overall accuracy of ultrasonographic analyses was 77.83%, and the sonographic criterion of irregular margin showed the highest predictability followed by the size. The correlation of internal echo structure with histopathological findings was highly variable. Conclusion: The ultrasound parameters such as size, shape, margin, S/L ratio, and internal echo structure might assist in differentiation between benign and metastatic lymph nodes. Combining these findings should raise the accuracy, as each sonographic parameter has some limitation as a sole criterion.