Non-tuberculous mycobacterial lung disease presenting as a solitary pulmonary nodule

We report a case of Mycobacterium intracellulare pulmonary infection presenting as a solitary pulmonary nodule (SPN). A 35-year-old male was admitted due to a SPN in the right upper lobe which was detected on the chest radiography being examed due to recurrent cough for 1 year. The computed tomography (CT) revealed a spiculated nodule containing air-bronchogram, which was suspicious of malignancy. We performed transbronchial biopsy and the pathology showed granulomatous inflammation with caseous necrosis. Under the presumptive diagnosis of pulmonary tuberculosis, we started anti-tuberculous medication including isoniazid, rifampin, ethambutol, and pyrazinamide. In one month, however, the sputum culture was positive for Mycobacterium intracellulare. The follow-up chest CT showed slight aggravation of the previous lesions. Under the final diagnosis of Mycobacterium intracellulare pulmonary infection presenting as a solitary pulmonary nodule, we changed the regimen to rifampin, ethambutol, and clarithromycin. The follow-up chest CT after the completion of treatment, revealed resolution of the previous lesions. Copyright