Leboulleux S et al. (2007) Ultrasound criteria of malignancy for cervical lymph nodes in patients followed up for differentiated thyroid cancer. J Clin Endocrinol Metab 92: 3590–3594

Neck ultrasonography is widely used for follow-up of patients with differentiated thyroid carcinoma (DTC). However, fine-needle aspiration biopsy is frequently required to clarify uncertain findings. To evaluate the sensitivity and specificity of ultrasound criteria for malignancy, Leboulleux et al. compared the results of ultrasound scans with the pathological findings from dissected lymph nodes of 19 patients who underwent neck surgery for DTC recurrence.

Of 578 lymph nodes resected, 56 could be definitively matched by location, shape and size to lymph nodes detected by ultrasonography. Of these, 28 were classed as benign and 28 as malignant by pathological examination. Ultrasound criteria found to be indicative of malignant lymph nodes were hyperechoic punctuations and a cystic appearance; all lymph nodes with either of these characteristics were found to be malignant. In addition, 96% of lymph nodes with a short axis >5 mm were malignant, but only 61% of malignant lymph nodes have a short axis >5 mm. The presence of a hyperechoic hilum was 100% indicative of nonmalignancy. The specificities of node shape, loss of hilum, and hypoechogenicity were not sufficient to assess malignancy. Both the sensitivity and specificity of peripheral vascularization were >80%; therefore, the authors recommend use of Doppler imaging to examine the vascularization pattern of suspicious lymph nodes.

The authors conclude that lymph nodes with a visible hilum should be considered benign, whereas those with a cystic appearance or hyperechoic spots should be considered malignant, and the presence of peripheral vascularization is an indication for biopsy.