Clinicopathologic characteristics of nontuberculous mycobacterial lung disease in Taiwan

Taiwan is an endemic area for tuberculosis (TB), and the incidence of pulmonary infection caused by nontuberculous mycobacteria (NTMs) is also increasing. This study aims to investigate the clinicopathologic characteristics of patients with NTM lung disease during 1998 to 2007 at a medical center in Taiwan. The medical records of patients with confirmed NTM pulmonary infections who underwent open lung surgery in a medical center were reviewed. Twenty-four patients with confirmed NTM pulmonary infections were identified. These patients were histologically classified into 4 types: fibrocavitary/tuberculoid (n = 10), nodular bronchiectatic (n = 4), sarcoidal (n = 6), and other (n = 4). The fibrocavitary/tuberculoid type usually (90%) develops in the upper lobes of old patients with preexisting lung disease. Pulmonary TB (n = 7, 70%) was the major underlying disease before 2003. Nodular bronchiectatic type occurred mainly in the middle lobe of middle-aged women without preexisting lung disease. Sarcoidal type was usually associated with Mycobacterium avium complex infection and develops in middle-aged women. Immunoreactive bacilli were detected in 21 patients (87 %) by immunohistochemical staining using a polyclonal antibody against Mycobacterium tuberculosis and other mycobacterial species (M. avium-intracellulare, Mycobacterium phlei, and Mycobacterium parafortuitum), whereas conventional acid-fast staining was positive in only 21% of patients. In conclusion, TB was the major underlying disease in patients with NTM lung disease in Taiwan. The different histologic types of pulmonary NTM infection suggest each had a distinct pathogenesis.