Differential diagnosis of cervical lymph nodes in head and neck cancer by ultrasonography

Objective: Determination of whether an enlarged cervical lymph node is metastatic or not is clinically important in head and neck oncology. Differential diagnosis of the lymph node, however, is still a diagnostic problem. The purpose of this study is to clarify the ultrasonographic findings of the metastatic lymph nodes of head and neck squamous cell carcinoma and to establish the criteria. Methods: We investigated 36 metastatic lymph nodes in head and neck squamous cell carcinoma and 24 non-metastatic nodes in benign disease with a 10-MHz transducer. We examined the size, shape, and internal echo (echo level, punctate bright echogenic spots, hilus echogenic line, cystic pattern) of these nodes. Based on this investigation, we evaluated 70 lymph nodes from 25 other patients by ultrasonography. Results: The short axis diameter and shape of metastatic nodes were larger and rounder than those of non-metastatic ones. Of the metastatic nodes, 69% showed hypoechoic and 31% isoechoic levels, and 78% exhibited punctate bright echogenic spots. Of the non-metastatic nodes, 92% showed hypoechoic and 8% isoechoic levels, and none of them showed the spots. The hilus echogenic line was not present in any metastatic node, but it was seen in 58% of non-metastatic ones. Of the metastatic nodes, 19% exhibited a cystic pattern; none of the non-metastatic nodes showed the pattern. According to our criteria based on these results, the accuracy rate was 98.6% (69/70). The sensitivity and specificity were 97.2% (35/36) and 100% (34/34), respectively. The false positive rate and the false negative rate were 0% (0/70) and 1.4% (1/70), respectively. Conclusion: Internal echo findings and shape of lymph nodes can be an important diagnostic tool, and our ultrasonographical criteria of the lymph nodes are very useful for the differential diagnosis of the cervical lymph nodes.