[Diagnosis of a malignant lymph node]

There are several imaging techniques, each with advantages and limitations. Standard or computed radiography is always useful. CT diagnosis of an enlarged lymph node is easy but it is very difficult to conclude about its reactive or metastatic nature: subtle signs can help. MRI has similar pitfalls but sometimes it may be possible to identify fibrotic scarred nodes. US with Doppler can evaluate the abnormal angioarchitecture of a metastatic lymph node. Sentinel lymph nodes are easily identified by nuclear medicine. CT-PET provides morphologic and metabolic information which increases the diagnostic accuracy. Imaging work-up strategies for selected malignancies are discussed.