Ultrasonographic diagnosis of cervical lymph nodes.

Many patients visit outpatient clinics suffering from cervical lymphadenopathy. For those patients, ultrasonography is useful in differentiating inflammatory diseases and malignant tumors. On ultrasonographic images, normal lymph nodes are indicated as hypoechogenic masses with a well-defined border. The medullary portion near the lymph node hilum is hyperechogenic, so-called fatty hilum (FH). Color Doppler imaging reveals that blood flows from the lymph node hilum to FH. In lymph node metastasis, a metastatic focus grows within lymph nodes, which displaces and destroys the structure of normal lymph nodes. Ultrasonography can be used to detect FH, disappearance and unevenness of blood flow within lymph nodes, cyst formation, and so on. It is important to closely observe the inside of lymph nodes and make a diagnosis via ultrasonography, based on the criteria for diagnosing lymph node metastasis from head and neck squamous cell carcinoma. Additionally, it is also necessary to distinguish among inflammatory lymphadenopathy and malignant lymphoma.