[A case of M. avium lung disease complicated with adenocarcinoma].

A 56-year-old man was admitted to our hospital for examination of an abnormal shadow found in a chest radiograph. Chest CT demonstrated a thick-walled cavity surrounded by small centrilobular nodules in the upper lobe of the left lung. Chemotherapy with rifampin, isoniazid, ethambutol and pyrazinamide was started, because acid-fast bacilli were observed in the bronchial brushing smear. Since PCR examination of the bronchial lavage was positive for M. avium, the rifampin and ethambutol were retained, while the other drugs were replaced with streptomycin and clarithromycin. However, in this case the radiographic findings did not point to non-tuberculous mycobacterial (NTM) infection, since the thickness of the cavity was irregular in the caudal portion. In addition, the patient did not accept long-term NTM therapy. Therefore, we chose surgical therapy. In a portion of the surgical specimen, adenocarcinoma was detected. The possibility of lung cancer should be remembered in cases with a thick-walled lung cavity.