Ultrasound Criteria for Malignancy in Cervical Lymph Nodes: Shape, Hilum, Blood Flow
General Assessment Principles
Ultrasound accurately differentiates between benign and malignant lymph nodes and surpasses CT and MRI for nodes accessible to scanning; the method also allows for ultrasound-guided core biopsy (Tru-Cut or Franseen), which is preferable to FNA (Diagnostic Ultrasound: Musculoskeletal, Griffith, 2025). Size is important, but it should be considered alongside other parameters: nodal configuration, cortical thickness, internal architecture, presence of calcifications, necrosis, vascular pattern, matting, and perinodal edema.
Size and Shape
According to Diagnostic Ultrasound: Musculoskeletal (Griffith, 2025):
| Feature | Characteristic |
|---|---|
| Normal Node | Long axis < 8 mm |
| Reactive Node | Long axis usually > 8 mm |
| Shape of Reactive Node | Ellipsoid/ovoid, long to short axis ratio > 2 |
A reactive node has a hypoechoic cortex compared to the adjacent muscle, with variable hyperplasia (thickening) of the cortex, leading to a lobulated cortical contour.
Cortical Contour and Extranodal Spread
An irregular cortical contour indicates extranodal spread (Griffith, 2025).
Internal Architecture
Intranodal cystic changes are found in metastases of squamous cell carcinoma or melanoma (Griffith, 2025). In metastatic involvement, a partially cystic node structure may be detected; for suspicious nodes, core biopsy targeting the node cortex is preferred if technically feasible.
Blood Flow
Assessment of the vascular pattern is among the key parameters for differential diagnosis (Griffith, 2025). Two- and three-dimensional classifications of vascular patterns in cervical lymphadenopathy have been developed based on power Doppler data (Wu et al., J Ultrasound Med, 1998). [Note: specific Doppler criteria for malignancy are not provided in the fragments]
Special Situations
In follow-up after thyroidectomy for papillary thyroid cancer, ultrasound criteria for malignancy of cervical lymph nodes developed for differentiated thyroid cancer are applied (Leboulleux et al., J Clin Endocrinol Metab, 2007; AIUM, 2023).
Frequently asked questions
What axis ratio is characteristic of a reactive node?
A reactive (benign) node has an ellipsoid/ovoid shape with a long to short axis ratio greater than 2 (Griffith, 2025).
What size of the long axis is considered normal?
A normal node has a long axis less than 8 mm; a reactive node usually exceeds 8 mm in the long axis (Griffith, 2025).
What does an irregular cortical contour indicate?
An irregular cortical contour indicates extranodal tumor spread (Griffith, 2025).
In which tumors are cystic changes in the node found?
Intranodal cystic changes are characteristic of metastases from squamous cell carcinoma or melanoma (Griffith, 2025).
Which is preferable, FNA or core biopsy?
For suspicious nodes, an ultrasound-guided core biopsy (Tru-Cut or Franseen) targeting the node cortex is preferred over FNA (Griffith, 2025).