Detection of suspicious malignant cervical lymph nodes of unknown origin: diagnostic accuracy of ultrasound-guided fine-needle aspiration biopsy with nodal size and central necrosis correlate.

Objective: To assess the role of ultrasound-guided fine-needle aspiration biopsy (US-guided FNAB) in the diagnostic workup of suspicious malignant cervical lymph nodes in patients with palpable neck masses and without known primary cancer. The diagnostic accuracy of imaging morphologic criteria, including sizes and central necrosis for assessing suspicious malignant nodes, were also examined.

Methods: This is a retrospective study of 426 patients with palpable neck masses from an outpatient department evaluated with computed tomography, magnetic resonance imaging, or US. US-guided FNABs were performed in 102 patients with suspicious malignant cervical lymph nodes at a single institution. Cytologically positive lymph nodes (n = 12) were further validated with excisional biopsy. Negative lymph nodes (n = 90) were either excised (n = 10) or followed up by imaging studies for at least one year (n = 80). The diagnostic accuracy of the FNABs along with the imaging findings of nodal sizes and presence of central necrosis, which were classified by a consensus of 2 radiologists, were assessed.

Results: Twelve malignant nodes were detected with US-guided FANB with one false-positive and one false-negative result. The overall sensitivity, specificity, and accuracy for FNAB were 91.7%, 98.9%, and 98.0%, respectively. The sensitivity, specificity, and accuracy were 66.7%, 30.0%, and 34.3% for size criterion and 75.0%, 83.3%, and 82.3% for central necrosis criterion.

Conclusions: The size of cervical lymph node does not appear to be an important imaging criterion for assessing suspicious malignant lymph nodes, compared with the criterion of central necrosis. US-guided FNAB is highly specific and sensitive in the diagnostic workup of suspicious malignant cervical lymph nodes in patients without known primary cancers.