Endobronchial ultrasound sonographic characteristics of mediastinal lymph node in the evaluation of lung cancer

Endobronchial ultrasound (EBUS) and contrast-enhanced computed tomography (CECT) are essential components of lung cancer evaluation. Features of mediastinal lymph nodes on EBUS and CECT can help in predicting metastatic disease. Clinical, radiological, and EBUS data of patients with clinico-radiological suspicion of lung cancer who have undergone EBUS with no transbronchial needle aspiration (TBNA) or nonyielding EBUS-TBNA were retrospectively collected from medical records. EBUS features of lymph nodes for metastatic disease [size >1 cm, round shape, heterogeneous echotexture, indistinct margin, coagulation necrosis (CN), absence of central hilar structures (CHS), and grade II-III vascularity] were noted. CECT findings were noted from CECT films and reports to analyze and compare with EBUS findings. Scoring criteria of EBUS sonographic characteristics from previous studies for discriminating benign and malignant lymph nodes were also assessed for possible prediction. 31 patients [male: 18 (58.1%), female: 13 (41.9); age (mean ± standard deviation): 52.9±15.7 years] with CECT findings suggesting lung cancer were studied. EBUS showed mediastinal lymphadenopathy at 82 lymph node stations in 29 patients. Size >1 cm, round shape, heterogeneous echotexture, distinct margin, CN, absence of CHS and grade II-III vascularity at 33 (40%), 28 (34%), 31 (38%), 55 (67%), 3 (4%), 77 (94%), and 6 (7.3%) lymph nodes, respectively, were found. The malignant or benign status assigned to lymph nodes using different scoring criteria was highly discordant. Compared to EBUS, CECT revealed abnormal mediastinal lymph nodes in significantly fewer patients [21 (67.7%) versus 29 (93.5%), p=0.01] involving a lower number of lymph node stations (37 versus 82, p<0.001). Lymphadenopathy frequency at different LNS on EBUS and CECT showed a weak positive but significant correlation (r=0.356; p=0.0426). EBUS characteristics and related scores have limited accuracy in differentiating benign and malignant nodes. CECT underestimates lymphadenopathy in comparison to EBUS. A larger prospective study of EBUS features with cyto/histopathology correlation may elicit its clinical significance and help to create better and more composite scoring criteria.