Abstract
During the 13 year period of 1982 to 1994 we had 103 patients with pulmonary Mycobacterium avium complex (MAC) infections. All met the citeria of atypical mycobacteriosis (Japanaese Mycobacteriosis Research Group of the National Chest Hospitals). Of 103 patients 70 had no underlying pulmonary diseases and classified as primary type.
Radiographic features of chest X-rays or computed tomography (CT) of primary infection were evaluated.
Results obtained were as follows:
1. Primary infection of MAC was classified into two types. One was localized type. This type was further classified into three patterns; tuberculosis-like pattern, pneumonia pattern in the lingula and/or middle lobe and pneumonia pattern in other lobes. Another one was diffuse type.
2. Tuberculosis-like pattern was most common in males. On the other hand, the pneumomia pattern and the diffuse type were most common in females.
3. Four characteristic features were seen as follows (Type 1-4) in the chest CT examination of diffuse pattern. Type 1: Nodules near the pleura. Type 2: Nodules with subpleural thickening.
Type 3: Bronchial wall thickening and ectatic change of the draining bronchi. Type 4: Cystic bronchiectatic change associated with atelectasis of the segment or the lobe. Bronchiectatic changes became severe and widespreaded in all lung fields as the disease progressed slowly. These findings were more prevalent in the lingula and/or middle lobe than the other lobes.
