1652 - Diagnoses of Non- Tuberculosis Mycobacterium (NTM) in patients with granuloma on lung biopsy

Background: The prevalence of non-Tuberculous mycobacteria (NTM) lung disease has increased from 8.7 to 13.9/100,000 from 2008-2013 making NTM lung disease a rising public health problem. Patterns of infection include fibrocavitary, bronchiectatic or nodular. Diagnosis of NTM may be incidental after surgical resection performed during malignancy work up.  We aimed to identify the proportion of NTM in resected lung lesions (both nodules and masses) with granulomas (GL) both necrotizing (NGL) and non-necrotizing (n-NGL) on pathology and to compare differences in characteristics of patients with NTM versus those without NTM. 

Methods: This was a retrospective chart review of patients who underwent resection of lung nodules and/or a lung mass during malignancy work up from January 2013 through March 2019 including only those with granulomatous inflammation on pathology. 497 patients met these criteria and their electronic medical records were reviewed. Findings of culture-confirmed NTM on tissue, bronchoalveolar lavage or sputum (at time of resection) were classified as “NTM” group; and those with no NTM diagnoses were classified as “Non-NTM” group. Patients with NTM and another diagnoses were classified within the NTM group. Study variables were compared by the dichotomous NTM group using Chi-square test for categorical variables and T-test for continuous variables.

Results: Among all patients, the most common diagnosis was lung cancer (21.93%). There were 81 (16.3%) patients with NTM (Table 1). Within the NTM group, percentage of Asians, presence of NGL, placement on airborne precautions and prior history of tuberculosis were significantly higher. The NTM group also had a higher proportion of both COPD and lung cancer as their underlying condition (Table 2).  161 patients had non-diagnostic biopsies.Table 1
Table 2
Table 2


Conclusion: Mycobacterial infections made up a significant percentage of resected lung nodules and/or lung masses for malignancy evaluation. NTM were isolated with greater frequency than M. Tuberculosis even with NGL on lung pathology. This reflects the changing epidemiology of NTM. The significant proportion of Asians with NTM compared with GL found during a malignancy work up without NTM is interesting and deserves further investigation.