Ultrasound investigation of cervical lymph node metastases: conception and results of a histopathological exploration

BACKGROUND: Ultrasound (US) is one of the most important methods for detection of cervical lymph node metastases in malignancies of the head and neck. In our study, the specificity of ultrasound was explored by a special, histopathological exploration considering the anatomical regions of the neck. METHODS: Thirty-eight patients were studied (5 female, 33 male, age: 38-86 years) with different histology and incidence of metastatic spread of head and neck cancers. Forty-six neck dissections were performed (30 radical and 16 selective). Histological exploration was performed after pinning the neck soft tissue with needles to anatomical live drawings of the lymph node regions, a modification of the Medina procedure. This procedure allowed a correct topographical assignment of lymph node metastases and comparison of preoperative sonographical findings with histopathological results. RESULTS: We isolated 1333 lymph nodes, 137 of them infiltrated by metastases. These lymph node metastases were found in 28 of 46 neck dissections. The number of lymph nodes in radical neck dissections ranged from 21 to 60 (mean: 36), in selective neck dissection from 1 to 43 (mean: 16). Sensitivity, specificity, and accuracy of ultrasound reached 96%, 69%, and 78%, respectively. Seventy-two lymph node metastases (52%) of 12 neck dissections could not be evaluated by ultrasound. CONCLUSIONS: Our results confirm the reliability of ultrasound regarding sensitivity, specificity and accuracy of US-detectable cervical lymph nodes as reported in world literature. However, we were able to demonstrate in special histopathological explorations, that ultrasound did not detect more than 50% of present lymph node metastases in our series. We consider it essential to perform histopathological explorations of the soft tissue of the neck as described in our study to evaluate the efficacy and reliability of US, CT, and MRI in detecting lymph node metastases of head and neck malignancies.