Ultrasound Skills and Application Beyond the Pleura
Cervical, supraclavicular, and axillary lymph nodes are accessible with ultrasound, and ultrasound may aid in distinguishing reactive from malignant lymph nodes. Inflammatory lymph nodes have an echogenic fatty hilum and oval or triangular shapes, compared to malignant nodes, which are often bulky and show loss of the fatty hilum, leading to a hypoechoic appearance (Figure 10.1a). Irregular borders are suggestive of extracapsular spread. Ultrasound-guided fine-needle aspiration (FNA) of supraclavicular lymph nodes is standard practice in many institutions, and has the advantage of providing a cytological diagnosis and pathological staging (pN3) in one minimally invasive procedure. A recent report highlighted the usefulness of ultrasound-guided FNA of supraclavicular lymph nodes: The procedure provided pathological diagnoses in 18.7% (95% CI = 15.9-20.5%) of all cases of lung cancer diagnosed over a 2-year period (n = 996).4 Ultrasound has the added advantage that it can be used to visualize cervical or supraclavicular lymph nodes in patients who present with superior vena cava obstruction, particularly when swelling and vascular congestion complicate routine physical palpation (Figure 10.1b-clip).