Infection with Mycobacterium avium presenting as polypoid lesions in left upper-lobe bronchus of an immunocompetent host

Abstract

In April 1993, a 51-year-old woman had a fever, and an infiltrative shadow was seen in the left upper lobe on a chest X-ray film. Repeated sputum cultures were positive for Mycobacterium avium complex. She underwent antituberculosis therapy consisting of pyrazinamide, ofloxacin, and streptomycin. Her symptom disappeared and the abnormal shadow resolved. In January 1994, she was admitted to the hospital because of bloody sputum and abnormal chest X-ray findings consisting of a left hilar mass and atelectasis of the left upper lobe. Bronchoscopy revealed multiple polypoid lesions without necrosis in the left upper-lobe bronchus. Histological examination showed that the tumor consisted of an aggregation of lymphocytes and plasma cells, and was positive for Ziehl-Neelsen stain. The acid-fast bacillus was identified as Mycobacterium avium by the DNA probe method. Anti-tuberculosis treatment was given: rifampicin, isoniazid, sparfloxacin, and clarithromycin. Three months later, the atelectasis and the polypoid mass in the left upper-lobe bronchus had disappeared. We believe that the polypoid lesions in the left upper-lobe bronchus were due to infection by Mycobacterium avium. The patient was HIV-negative and immunocompetent. Such endobronchial lesions caused by Mycobacterium avium are rare in HIV-negative hosts.