[Interstitial pneumonia with anti-PL-7 antibody difficult to distinguish from rheumatoid lung].

A 63-year-old woman had abnormal shadows on a chest radiograph taken on a medical examination during treatment for rheumatoid arthritis. The chest radiograph showed linear and reticular shadows and ground glass opacities in the bibasilar lung fields. Though we considered rheumatoid arthritis due to joint disorder and a positive reaction for serum anti-CCP antibody, there were no bone lesions or articular narrowing on radiographs of the fingers. We diagnosed antisynthetase syndrome after we obtained a positive reaction for serum anti-PL-7 antibody. Antisynthetase syndrome demonstrates findings similar to those of rheumatoid arthritis, and this disease should be taken into consideration if chest computed tomography demonstrates consolidation with predominant patchy and irregular bronchovascular bundle thickening with a subpleural distribution.