[Usefulness of bronchoscopy for the diagnosis of atypical pulmonary mycobacteriosis].

In 14 subjects whose chest radiographs showed abnormal shadows during the two years from January 1995 until December 1996, no definite diagnosis could be obtained because sputum, smears and cultures all gave negative results for mycobacteria. Bronchoscopy was therefore performed, revealing atypical mycobacteria in cultures of the bronchial washing fluid for mycobacteria, and the significance of bronchoscopic examinations in cases diagnosed an atypical pulmonary mycobacteriosis was investigated. Most of the subjects (9) were women. Nine subjects had been informed that they had abnormal chest shadows; five had subjective symptoms; bloody sputum, 3 and cough, 2. The characteristics of the shadows were as follows: in the plain radiographs, the main shadows had a mottled or granular appearance in the majority of the patients (9) and there were infiltrative shadows in 3 patients and nodular shadows in another 3. In computed tomograms, the shadows in the vicinity of the pleura appeared as micronodular conglomerates in 12 patients, in 11 of whom bronchiectasis was also present near the shadows. Alveolar infiltrative shadows were present in four cases, and a cavity was seen in only one. Smears of the bronchial washing fluid for mycobacteria were positive in 7 patients, and cultures of this fluid yielded at least 100 colonies in 8 of the 14 subjects for whom the results were positive. By culture, Mycobacterium avium complex (MAC) was identified in 13 patients, but eleven of these in whom the bronchial washing fluid was concurrently tested for MAC by the polymerase chain reaction, only four were MAC-positive. Transbronchial lung biopsies were performed in 11 cases, in which the histological findings of mycobacterial infections showed granuloma in four, and caseation in three. Bronchoscopy is making possible initial-stage diagnosis, which are normally difficult, among the recently growing number of cases of the bronchial form of atypical pulmonary mycobacteriosis and is also useful for reaching definite diagnosis in the early stage.