Background Tuberculosis(TB) remains a global public health concern.¹ It is one of intrathoracic lymphadenopathy(ITLN) numerous causes and must be taken into account in differential diagnosis, especially in endemic countries.² Diagnostic yield of EBUS-TBNA for mediastinal and hilar TB has been reported to be 80%.²

Aim To determine the prevalence of TB in patients with ITLN undergoing EBUS-TBNA and calculate diagnostic yield.

Methods Retrospective study of all patients undergoing EBUS-TBNA for ITLN, from August/2011 to March/2017. Clinical, laboratorial, histopathological and radiological data were assessed. We considered for diagnosis by EBUS-TBNA all cases with TB confirmed and granulomatous lymph node with TB confirmation by other methods.

Results 186 patients were included, mean age of 57 years (SD=14), 53.8% male. Granulomatous disease was diagnosed in 29% (n=54), 42.6% (n=23) with cancer diagnosis or suspicion at the time of procedure. Sarcoidosis was diagnosed in 15.6% (n=29), mycobacteriosis in 9.7% (n=18), fungal infection in 2.7% (n=5) and other granulomatosis in 1% (n=2). Mycobacteriosis was due to M.tuberculosis in 88.9% (n=16), M.kansasii in 5.55% (n=1) and M.avium in 5.55% (n=1). EBUS-TBNA established the diagnosis in 56.3% (n=9) of TB cases: 25% (n=4) caseous granuloma in cell block, 18.8% (n=3) positive acid-fast bacilli (AFB) and 12.5% (n=2) M.Tuberculosis in aspirated sample culture. In 37.5% (n=6) cell block from EBUS-TBNA showed granulomas but definite diagnosis was made by presence of caseous granuloma in biopsy (12.5%,n=2) or positive AFB (6.25%,n=1) in other organs, positive PCR of bronchoalveolar lavage in 6.25% (n=1) or pleural fluid in 6.25% (n=1), and sputum culture in 6.25% (n=1).One patient needed mediastinoscopy. 25% (n=4) of patients diagnosed with TB had cancer and 31.6% (n=5) was submitted to EBUS-TBNA for cancer suspicion. In our setting, the prevalence of TB was 8.6% and the diagnostic yield of EBUS-TBNA was 77.7%.

Conclusions Our study showed granulomatosis in 29% of patients with TB as second most frequent cause.Brazil belongs to the five countries that collectively account for about 50% of the world TB cases¹ and, despite lymphadenopathy is not a major form of TB, our study emphasises its importance in differential diagnosis of ITLN in endemic countries. EBUS-TBNA showed to be a useful diagnostic tool.

References

1. World Health Organisation. Global tuberculosis control: WHO report2016. http://apps.who.int/iris/bitstream/10665/250441/1/9789241565394-eng.pdf?ua=1

2. Li W, et al. Diagnostic value of convex probe endobronchial ultra sound-guided transbronchial needle aspiration in mediastinal tuberculous lymphadenitis: A systematic review and meta-analysis. Med Sci Monit2015, Jul 16;21:2064–72.