Histologically controlled comparison of palpation and sonography in the diagnosis of cervical lymph node metastases

During a period of 2 1/2 years palpation and high-resolution real-time sonography were carried out in 83 non-selected patients with head and neck carcinomas to diagnose metastatic involvement of cervical lymph nodes. The findings were compared with the results of the microscopic examination of the lymph nodes from the neck dissection specimen. Sonography is characterized by a high sensitivity in the detection of lymph node metastases. The relatively low specificity of this method proves that many enlarged but not metastatically involved lymph nodes are also displayed by ultrasound. Although there are no specific echomorphological criteria permitting a reliable identification of lymph node metastases, their sonographic visibility cannot be determined only by the size of the lymph node. Lymph node metastases less than 1.5 cm in diameter, in particular, can be detected more often by ultrasound than by palpation. Therefore, it can be presumed that pathological transformations besides the reactive hyperplasia occurring during metastatic involvement will also influence the echographic representation of lymph nodes. The accuracy data of other methods used for detecting lymph node metastases (computed tomography and lymphoscintigraphy) were compiled from the literature and compared with those of palpation in more than 5000 patients. Basing on our experiences with sonography in this field we tried to assess the chances and limitations of ultrasound in the pretherapeutic diagnosis of cervical lymph node metastases.