Pitfalls in the staging of cervical lymph node metastasis.

Lymph nodes status is an important predictor of prognosis in head and neck squamous cell carcinoma, making accurate staging critical. The physical examination of the neck is highly inaccurate. CT, MR imaging, ultrasound (US), and positron emission tomography-CT (PET-CT) improve accuracy but have limitations. Size criteria, nodal shape and clustering, central necrosis, and findings of extracapsular spread and vascular encasement suggest metastatic involvement on CT and MR imaging. US features help differentiate benign from malignant nodes, aided by US-guided fine-needle aspiration for indeterminate cases. PET-CT is useful for staging the lymph nodes and detection of distant metastasis.