Endobronchial Involvement of <i>Mycobacterium intracellulare</i> in a Patient with Previously Treated Lung Cancer

The incidence of nontuberculous mycobacterial pulmonary disease is increasing, and Mycobacterium avium complex (MAC) is the most common causal species. Patients with underlying structural lung disease or an immunosuppressive condition are at increased risk for MAC infections. Endobronchial lesions caused by MAC infection are extremely rare, especially in immunocompetent hosts. Here, we describe a case of a 58-year-old woman with pulmonary infiltration and endobronchial involvement caused by MAC. The patient had shortness of breath and a productive cough. She had undergone surgery and chemoradiotherapy for lung cancer 10 years prior. Radiological findings revealed small centrilobular nodules with consolidation in the right lung and mild stenosis at the right main bronchus. Bronchoscopy revealed yellowish-white caseous necrosis in the right main bronchus. Mycobacterium intracellulare was identified in bronchial washing fluid. She was treated with antimicrobial medications. After 6 months of treatment, bronchial lesions, radiological findings, and symptoms had improved remarkably and she showed culture conversion.