sonographic features of malignant lymph nodes

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sonographic features of malignant lymph nodes

Lymphadenopathy is quite common, and it can be very difficult to differentiate malignant lymphadenopathy from reactive nodal enlargement.

Several gray scale and color Doppler features favor malignancy in a lymph node.

Gray scale parameters that favor malignancy
  • size: larger - more likely malignant
  • shape: round, long axis/short axis <2
  • echogenicity: predominantly hypoechoic although metastastic lymph nodes from papillary thyroid carcinoma tend to be hyperechoic due to the intranodal deposition of thyroglobulin 
  • heterogenous echotexture
  • loss of central fatty hilum/thinning of hilum
  • eccentric versus concentric thickening of cortex
  • presence of microcalcifications
  • necrosis: cystic/coagulative
  • ill-defined capsular margins: invasion
Color/power Doppler features that favor malignancy
  • peripheral/mixed peripheral: central blood vessels
  • high resistance waveform
  • RI >0.8, PI >1.5
  • aberrant vessels: displaced parent vessels, subcapsular vasculature, non-perfused areas, non-tapering vessels

The increase in resistivity in a malignant lymph node is attributed to increased cellularity within an infiltrated lymph node. However, malignant lymph nodes with necrotic change may show low resistance flow due to loss in the cellularity following necrosis and this needs to be kept in mind while interpreting this sign.

When used in combination the above signs can help differentiate a malignant lymphadenopathy from reactive nodal enlargement.

Imaging in practice
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