Dermatomyositis associated with rapidly progressive fatal interstitial pneumonitis and pneumomediastinum.

We describe two cases of dermatomyositis (DM), which subsequently developed into rapidly progressive fatal interstitial pneumonitis and pneumomediastinum during steroid therapy. Both cases showed the classical cutaneous manifestations of DM, but the muscular symptoms were absent or mild. Both rapidly progressive interstitial pneumonitis and pneumomediastinum can occur in DM showing less inflammatory changes in the muscles. Patients with this form should be treated with extreme caution.