Endobronchial seeding of tuberculous granulomas after EBUS-TBNA of mediastinal lymph nodes.

A 36-year-old non-smoking immunocompetent female patient was admitted due to cough, weight loss, and general malaise. A CT scan revealed a tumor in the left upper lobe with pathological mediastinal lymph nodes. Bronchoscopic biopsy of the tumor and EBUS lymph nodes 11L, 7, and 4R were performed. Histological examination revealed granulomatous inflammation with necrosis and rare tuberculouse bacilli (Figure 1). Cultures remained negative, but Xpert MTB/RIF assay was positive for tuberculosis and negative for antibiotic resistance. The patient received standard six-month tuberculosis therapy, but the lymph nodes and the lesion itself slightly increased on the follow-up CT after six months, and new endobronchial lesions appeared, corresponding to the puncture sites. Upon repeat bronchoscopy, tumor-like growth were found at all three sites previously sampled with EBUS-TBNA, which were completely excised (Figure 2). Histological examination showed granulomas with necrosis but without the presence of bacteria, fungi, or TB bacilli. Xpert MTB/RIF was still marginally positive (Figure 3). The patient, who clinically improved, was not reintroduced to therapy but was kept under careful observation for one year. During this time, the changes on CT regressed, and sputum cultures remained negative. In this presented case, we describe iatrogenic fistulas that developed at the sites of puncture tracts created by previous EBUS-TBNA, through which tuberculosis spread into the airway lumen. Endobronchial seeding after EBUS-TBNA has been likely underreported in the literature (1-2). Similar fistulas could also form in the esophagus in the case of EUS-B, although they have not been reported so far. However, we believe it is important to highlight and recognize the tendency of tuberculosis to form fistulas when considering invasive diagnostics of mediastinal lymph nodes in suspected tuberculosis cases.