Nodal metastasis is the spread of cancer to regional or distant lymph nodes, representing an important factor in cancer staging and prognosis. On ultrasound, metastatic lymph nodes may appear enlarged (typically >10 mm in short axis, though size criteria vary by location), rounded instead of the normal oval shape, lacking the normal fatty echogenic hilum, or showing hypoechoic cortical thickening. However, ultrasound criteria for lymph node malignancy are imperfect, and some benign nodes appear enlarged while some nodes with metastases appear normal in size. Ultrasound can guide biopsy of suspicious nodes to confirm metastatic disease. In cancer surveillance, lymph node assessment is an important part of staging studies and surveillance protocols.
Sonography Term