The Diagnostic Utility of Endobronchial Ultrasound-Guided Trans-Bronchial Needle Aspiration (EBUS-TBNA) in Non-Malignant Mediastinal Lymphadenopathy: Experience from a High Tuberculosis Burden Tertiary Center

Introduction Mediastinal lymphadenopathy is a common radiological entity, with myriad etiologies. A significant proportion of the published literature on Endobronchial ultrasound-guided trans-bronchial needle aspiration (EBUS-TBNA) is focused on the diagnostic and staging aspects of lung cancer. However, the value of EBUS-TBNA in a high tuberculosis burden setting is not well established. We therefore sought to assess the diagnostic utility of EBUS-TBNA in suspected non-malignant mediastinal lymphadenopathy in a tertiary care referral center in North India. Methods In this prospective study, consecutive patients with suspected non-malignant mediastinal lymphadenopathy were included and underwent clinical assessment and contrast-enhanced computed tomography (CECT) to establish a baseline clinico-radiological-laboratory diagnosis (CRLD). EBUS-TBNA was performed, and aspirates were sent for cytology and microbiological tests for TB. In cases of non-diagnostic EBUS-TBNA, CRLD was used to guide therapy. Treatment was instituted, and follow-up was done at 6 months. The sensitivity, specificity, positive and negative predictive values of EBUS-TBNA were calculated on the basis of final diagnosis at 6 months. We also evaluated diagnostic utility of EBUS-TBNA as the percentage of patients wherein EBUS-TBNA diagnosis led to an alteration of management over CRLD-guided treatment. Results Ninety-six patients underwent the procedure, of which 55 (57%) had adequate and 47 (49%) had diagnostic EBUS-TBNA, respectively. Among those with adequate EBUS, TB was the most common diagnosis in 29 (53%) patients, followed by sarcoidosis in 14 (25%). One patient was diagnosed with non-TB mycobacterium infection, three patients had malignancy, and eight specimens showed reactive lymphadenitis. The sensitivity for diagnosis of TB and sarcoidosis was 85% and 88%, respectively, with a negative predictive value of 100% for both diagnoses. The diagnostic utility of an adequate EBUS-TBNA was 22% over CRLD, and 77% in cases where CRLD was indeterminate. The adequacy of EBUS-TBNA was significantly higher with lymph node size 2 cm compared to < 2 cm (63% vs. 37%, P < 0.001). Conclusion EBUS-TBNA is a valuable method in the evaluation of suspected non-malignant mediastinal lymphadenopathy in a high-TB-burden setting, providing specific diagnosis in about half of the patients. If adequate samples are obtained, utility of EBUS-TBNA is 22% overall and 77% in cases with indeterminate CRLD. The adequacy of procedure is significantly higher with lymph node size 2 cm.