Clinical characteristics and outcomes of surgically resected solitary pulmonary nodules due to nontuberculous mycobacterial infections

Granulomas caused by nontuberculous mycobacterial (NTM) pulmonary infections can present as solitary pulmonary nodules (SPNs) mimicking pulmonary malignancies or other infectious granulomas. However, limited data are available regarding the detailed characteristics and outcomes of surgically resected NTM granulomas. We evaluated the characteristics of 49 surgically resected NTM granulomas presenting as SPNs of 49 patients between January 2007 and December 2016. Twenty-five (51%) were male and 27 (55%) were never-smokers. Seven (14%) patients had histories of tuberculosis and 14 (29%) histories of solid tumors. More than half (51%) of all patients were asymptomatic. On chest computed tomography, the median SPN diameter was 18 mm, and approximately half of all SPNs (49%) were located in the upper lobe. NTM were isolated from sputum (31%), bronchial wash fluid (33%), and biopsy specimens (63%). M. avium (71%, 22/31) was the organism most commonly isolated, followed by M. intracellulare (16%, 5/31). In terms of surgery, wedge resection through video-assisted thoracic surgery (86%, 42/49) was most commonly performed. Postoperative pneumothorax and atelectasis developed in four (8%) and one (2%) patients(s), respectively. Five patients received postoperative antibiotic therapy. Over a median follow-up period of 18 months (interquartile range 5–58 months), NTM pulmonary disease developed in one patient. Most NTM granuloma can be treated safely by surgical resection without postoperative antibiotic therapy, and microbiological examinations including mycobacterial culture of surgical specimens is important for optimal management of these patients.