Correlation of lymph node appearance features with histopathological diagnosis in cases with endobronchial ultrasound

Introduction: Sonographic criteria used to predict malignant lymph nodes by endobronchial ultrasonography (EBUS) vary. In this study, we aimed to determine the sonographic criteria of lymph nodes to predict malignancy with EBUS. Methods: The cases who underwent EBUS between May 2016 and July 2020 in Dokuz Eylül University Hospital Chest Diseases Department were retrospectively analyzed. EBUS images of lymph nodes were evaluated according to following criteria: size (short axis > 1cm or ≤ 1 cm), shape (round or oval), margin (distinct or indistinct), coagulation necrosis sign (present or absent), central hilar structure (present or absent) and echogenicity (homogeneous or heterogeneous) The correlation between sonographic findings and pathological examination results was investigated. Scoring (EBUS score; one point was given for each score) was developed with six criteria that were found to be significant for predicting malignancy. Results: A total of 1987 LN were analyzed in 967 patients. 765 lymph nodes (38.5%) were malignant. In univariate analysis; size > 1 cm, round shape,distinct margin, absence of central hilar structure, presence of coagulation necrosis sign and heterogeneity were found to be statistically significant in the prediction of malignancy (p for all <0,001). In the multivariate regression analysis; the most important parameters in predicting malignancy were "the presence of heterogeneous lymph nodes" and "signs of necrosis" (OR=5.9 %95 CI ([4.2-8.2], 3.1[2.2-4.5] respectively). The malignancy risk of those with an EBUS score of ≥4 was 30.0 (23.4-38.6) times higher than those with an EBUS score of ≤3. In the ROC analysis performed for the EBUS score, the cut off value was found to be 3.5. According to this cut off value was 84.7%, specificity 84.5%, positive predictive value (PPV) 77.3%, negative predictive value (NPV) 89.3%. Conclusion: EBUS scoring with six criteria has high sensitivity and specificity for predicting malignant lymph nodes.