[Relationship between the onset and outcome of interstitial pneumonia associated with polymyositis and dermatomyositis].

We investigated the outcome of 12 patients with interstitial pneumonia (IP) associated with polymyositis and dermatomyositis (PM/DM). The mean age of the patients was 53. There were 3 cases of PM/DM preceding the respiratory symptoms (RS), 7 cases of simultaneous PM/DM and RS, and 2 cases of PM/DM delayed with RS. In these 3 groups, there was a tendency for cases with PM/DM preceding RS to be younger. Jo-1 antibody was positive in only one case of the simultaneous group. Patients in whom IP preceded PM/DM or was simultaneous with PM/DM showed a better response to corticosteroid. The chest CT findings and TBLB findings showed a BOOP pattern in these patients. TBLB findings are not useful for diagnosing the pathological type, however they are useful for evaluating the effectiveness of steroid therapy on IP in PM/DM.