Pulmonary Infection of Mycobacterium aviumintracellulare Complex with Simultaneous Organizing Pneumonia

A 67yearold woman presented highgrade fever and dyspnea. Sputum culture confirmed Mycobacterium aviumintracellulare complex (MAC). Transbronchial lung biopsies revealed organizing pneumonia (OP) that was rapidly improved with corticosteroid. Five months after onset, a nodule emerged in the right lung. Although MAC was confirmed, the lesion was deemed too small to merit antimycobacterial chemotherapy. Four months later, diffuse infiltrates developed on chest Xray. Bronchoalveolar lavage study identified MAC and exhibited OP patterns. We commenced antimycobacterial chemotherapy. The infiltrates almost completely improved within a month without corticosteroid.