Metastatic lymphadenopathy from ENT carcinoma: role of diagnostic imaging

Problems concerning the use of different imaging modalities in N staging of the neck are dealt with. The peculiar features, findings, sensitivity, specificity and diagnostic accuracy of each modality in the diagnosis of nature of cervical lymphadenopathy are described, as reported in most recent reports of literature, and according to the personal experience. CT/MRI criteria commonly used to establish whether a lymph node is metastatic or benign/reactive are related to the size, morphology, density (CT), signal intensity (MRI), evidence of central necrosis and extracapsular spread. Color Doppler US is a reliable method in the diagnosis of cervical metastatic lymphadenopathy even if no parameter is highly predictive; the combination of different findings, especially cortical thickening and structural inhomogeneity with thin, compressed, displaced or non visualized hilum makes the procedure significantly sensitive and specific. Intranodal hilar vascularization on color Doppler, with high resistance arterial flow (PI > 1.5), enhances the predictive value of findings of bi-dimensional sonography. Extracapsular spread impacts on survival as well as on the number of recurrences, which increases in patients with extracapsular spread; the disease-free interval is less in these patients. The identification and definition of extracapsular spread is based on some CT/MRI criteria as: 1) lymph nodes with spiky, irregular margins; 2) loss of adipose cleavage planes around the node and thickening of adjacent fascia; 3) apparent invasion of an adjacent structures or muscles. Similarly to CT/MR, sonographic findings of extracapsular spread can be: 1) blurred margins and irregular contours; 2) invasion of an adjacent structure or muscle.