High-resolution CT findings of lung disease in patients with polymyositis and dermatomyositis.

The purpose of this study was to determine the type and distribution of interstitial lung disease seen in patients with polymyositis and dermatomyositis, using high-resolution computed tomography (HRCT). The presence and distribution of high-resolution CT findings were retrospectively evaluated in 25 patients with polymyositis/dermatiomyositis. In 14 patients, a pathological diagnosis of pulmonary disease was obtained. Three lung specimens were also studied. Results showed that 23 patients had abnormal HRCT showing the following abnormalities: ground glass opacities (92%), linear opacities (92%), irregular interfaces (88%), airspace consolidation (52%), parenchymal micronodules (28%), and honeycombing (16%). A relatively high prevalence of airspace consolidation (52%) and a low prevalence of honeycombing (16%) were observed. Two patients with extensive consolidation proved to have diffuse alveolar damage; eight patients with either subpleural band-like opacities (n = 5) and/or airspace consolidation (n = 7) had bronchiolitis obliterans organizing pneumonia; four patients with honeycombing had usual interstitial pneumonitis. We conclude that HRCT findings in patients with polymyositis/dermatomyositis are nonspecific. However, a high prevalence of airspace consolidation and a low prevalence of honeycombing were observed. Predominant HRCT patterns are suggestive of the pathologic processes occurring in polymyositis/dermatomyositis.