Two patients with polymyositis or dermatomyositis complicated with massivepleural effusion

Two patients with polymyositis (PM) or dermatomyositis (DM) complicated wit h massive pleural effusion are reported here. Both patients presented a hig h-grade fever, pleural effusion prominent on the right, and good response t o steroid therapy. In a 50-year-old woman with PM, combined process of pleu ral inflammation, cardiomyopathy and coexisting hypothyroidism were conside red to be responsible for the accumulation of the massive pleural effusion. However, in a 34-year-old man with DM, pleural inflammation associated wit h interstitial pneumonia or pleural microvasculopathy in DM was considered to be responsible for the accumulation of the massive pleural effusion.