Prior to the development of TBNA and its adaptation for use with the fiberoptic bronchoscope, mediastinal lymphadenopathy required more invasive diagnostic procedures such as mediastinoscopy, anterior mediastinotomy, or thoracotomy. A number of studies have now confirmed the utility of TBNA for diagnosing mediastinal cancer, thus often obviating the need for surgical intervention.- In addition, these studies have confirmed the safety of TBNA with most investigators not encountering complications of clinical significance.’ Nevertheless, despite the well-established role of fine-gauge TBNA for diagnosing mediastinal carcinoma, its usefulness in making benign diagnoses has been limited.
To overcome this limitation, Wang introduced 18-gauge flexible transbronchial needle aspiration biopsy to obtain histologic specimens of mediastinal lymph nodes. Benign diagnoses have been made using 18-gauge TBNA, but to our knowledge a TBNA diagnosis of mycobacterial disease involving the mediastinum has not been previously reported. It is quite possible that since most patients have had TBNA performed for the express purpose of diagnosing mediastinal cancer, acid-fast smear has not been routinely performed. This report, however, highlights the potential role of TBNA in diagnosing intrathoracic lymphadenopathy resulting from mycobacterial infection, hopefully sparing such patients more invasive operative procedures. Given the safety and technical ease of TBNA, it is our recommendation that during TBNA, at least one aspirate should be obtained for acid-fast smear and culture if a diagnosis of mycobacterial disease is being entertained.