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

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.

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.

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.

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