Transbronchial endosonography of mediastinal lymph nodes in the differential diagnosis of tuberculosis and other diseases

Introduction. Mediastinal lymphadenopathy poses a significant challenge in the differential diagnosis of nu-merous diseases, including tuberculosis. Transbronchial biopsy under endosonographic guidance (EBUS-TBNA) is a minimally invasive diagnostic method, widely rec-ognized as a preferred approach for invasive diagnos-tics. However, in the Russian Federation this method is taken with caution, and videothoracoscopic biopsy is often preferred. Aim: to investigate the diagnostic val-ue of endosonographic patterns identified during trans-bronchial endosonography of mediastinal lymph nodes in the differential diagnosis of tuberculous involve-ment. Materials and methods: a retrospective analysis was conducted on a prospectively recruited cohort of 185 patients with mediastinal lymphadenopathy who underwent EBUS-TBNA followed by videothoracoscop-ic biopsy for diagnostic verification. Ultrasonographic characteristics of lymph nodes, including shape, mar-gins, echogenicity, presence of central structures, signs of necrosis, calcification, and lymph node fusion, were analyzed. An economic evaluation was performed using a cost-minimization approach to compare EBUS-TBNA and videothoracoscopic biopsy. Results. Tuberculosis of intrathoracic lymph nodes was confirmed in 23 patients (12.4%), sarcoidosis stages 1–2 in 137 (74.1%), meta-static involvement in 11 (5.9%), and lymph node hyper-plasia in 11 (5.9%). Statistically significant predictors of tuberculous involvement included oval/irregular shape (p=0.009), unclear margins (p=0.012), necrosis (p=0.038), and lymph node fusion (p=0.020). The combination of these features increased the likelihood of tuberculosis by 3.1–4.8 times (positive predictive value 30.2%), with a negative predictive value of 93%. The median cost of videothoracoscopic biopsy was 123.6 c.u., compared to 72.3 c.u. for EBUS-TBNA. Conclusion. Characteristic endosonographic patterns of tuberculous mediastinal lymph node involvement were identified, serving as ad-ditional differential diagnostic criteria. The absence of these patterns reliably excludes tuberculosis. However, definitive verification requires morphological and/or mo-lecular-genetic confirmation, which is significantly more cost-effective than initial videothoracoscopic biopsy