[Clinico-pathological manifestations in interstitial lung diseases associated with polymyositis-dermatomyositis]

OBJECTIVE: Polymyositis-dermatomyositis has been associated with various histological patterns of interstitial lung disease (ILD). This study was to investigate the clinico-pathologic features of interstitial lung diseases associated with polymyositis-dermatomyositis.

METHODS: We retrospectively identified 26 patients with polymyositis-dermatomyositis associated ILD who underwent lung biopsies (6 autopsies, 5 surgical lung biopsies and 15 percutaneous lung biopsies) at our hospital during a 27-year period from January 1980 through October 2007. Histopathologic findings were analyzed and correlated with radiological features and outcome.

RESULTS: Median age was 48 years (range, 19 to 65 years), and 16 patients were women. Chest X-ray imaging revealed bilateral infiltrates including ground-glass attenuation, patchy infiltration, and reticular opacities. The major histopathologic patterns included diffuse alveolar damage (DAD) (n = 5), lymphocytic interstitial pneumonia (n = 2), nonspecific interstitial pneumonia (NSIP) (cellular pattern, n = 6; mixed pattern, n = 8), organizing pneumonia (n = 4), usual interstitial pneumonia (UIP) (n = 1). Treatment commonly included prednisone with immunosuppressive agent. During the follow-up period (median, 15 month,range from 6 to 108 month), 18 patients improved or remained stable. Eight patients died, including 5 deaths from DAD, 2 from NSIP mixed pattern, 1 from UIP.

CONCLUSIONS: A variety of histological patterns can be seen in patients with polymyositis-dermatomyositis-associated ILD. Those with DAD tended to have poor prognosis.