Surgical resection is sufficient for incidentally discovered solitary pulmonary nodule caused by nontuberculous mycobacteria in asymptomatic patients

Hung-Ling Huang,Meng-Rui Lee,Meng-Hsuan Cheng,Po-Liang Lu,Jann-Yuan Wang,Inn-Wen Chong,Chia-Jung Liu,Adriano Gianmaria Duse

doi:10.1371/journal.pone.0222425

Abstract

Incidentally discovered solitary pulmonary nodules (SPN) caused by nontuberculous mycobacteria (NTM) is uncommon, and its optimal treatment strategy remains uncertain. This cohort study determined the clinical characteristics and outcome of asymptomatic patients with NTM-SPN after surgical resection. Resected SPNs with culture-positive for NTM in six hospitals in Taiwan during January, 2010 to January, 2017 were identified. Asymptomatic patients without a history of NTM-pulmonary disease (PD) or same NTM species isolated from the respiratory samples were selected. All were followed until May 1, 2019. A total of 43 patients with NTM-SPN were enrolled. Mycobacterium avium complex (60%) and M. kansasii (19%) were the most common species. The mean age was 61.7 ± 13.4. Of them, 60% were female and 4% had history of pulmonary tuberculosis. The NTM-SPN was removed by wedge resection in 38 (88%), lobectomy in 3 (7%) and segmentectomy in 2 (5%). Caseating granuloma was the most common histologic feature (58%), while chronic inflammation accounts for 23%. Mean duration of the follow-up was 5.2 ± 2.8 years (median: 4.2 years [2.5-7.0]), there were no mycobacteriology recurrence or NTM-PD development. In conclusion, surgical resection is likely to curative for incidentally discovered NTM-SPN in asymptomatic patients without culture evidence of the same NTM species from respiratory specimens, and routine mycobacterium culture for resected SPN might be necessary for differentiating pulmonary tuberculosis and NTM because further treatment differs.

Highlights

With advances in and the widespread use of chest computerised tomography (CT), the detection rate of solitary pulmonary nodules (SPNs) has increased in recent decades, and the detection rate exceeded 50% among asymptomatic patients in some series [1, 2]
After applying a serial of exclusion criteria mentioned above, a total of 43 resected nontuberculous mycobacteria (NTM)-SPNs from 43 cases were selected for analysis
Mycobacterium avium complex (MAC) and M. kansasii accounted for 79% of the resected SPNs

Summary

Introduction

With advances in and the widespread use of chest computerised tomography (CT), the detection rate of solitary pulmonary nodules (SPNs) has increased in recent decades, and the detection rate exceeded 50% among asymptomatic patients in some series [1, 2]. A positive correlation between nodule size and the likelihood of malignancy has been demonstrated. A population-based study conducted in the United States and United Kingdom revealed that the vast majority of SPNs are benign, even in smokers [5]. In a study in Japan, among 25 benign lesions in 103 surgically removed SPNs, the responsible microorganism was Mycobacterium tuberculosis in 1 (4%) case and Mycobacterium avium complex (MAC) in 4 (16%) cases [8]. In a study conducted in the United States, only 1 (5%) of the 20 resected SPNs was culture-positive for M. tuberculosis, whereas 14 (70%) were positive for NTM [9]. In NTM-SPNs, MAC is the most commonly isolated species (70%–89%) [2, 10,11,12,13,14]

Methods

Results

Conclusion