Use of saline to evaluate a cavity due to Mycobacterium kansasii infection during ultrathin bronchoscopy and endobronchial ultrasonography

A 28‐year‐old man had a cavitary lesion in the upper right lobe with a tree‐in‐bud appearance on chest computed tomography (CT). Diagnostic bronchoscopy was performed. An ultrathin bronchoscope in the right B2aiiβxyy reached the cavity. We filled the cavity with saline under direct bronchoscopic visualization. We suspected a blood vessel was present in the cavity wall based on narrow‐band imaging. Bronchial lavage of the cavity was performed. Next, endobronchial ultrasonography (EBUS) using a guide sheath was performed with a thin bronchoscope. EBUS showed a pulsating blood vessel in the cavity wall. Bronchial lavage collected with ultrathin and thin bronchoscopy revealed Mycobacterium kansasii. Observation of vessels in the wall of a cavitary lesion with ultrathin bronchoscopy and EBUS may be useful for avoiding severe bleeding associated with biopsy of a cavitary lesion.