We described a 65-year-old woman who died of acute interstitial pneumonia associated with dermatomyositis. Subcutaneous emphysema and pneumomediastinum simultaneously developed. The association of the pulmonary rupture with vasculitis has been assumed as the common cause in interstitial pneumonia. Diffuse alveolar damage, however, might have led to the pneumomediastinum and subcutaneous emphysema in our patient, who had no signs of cutaneous vasculitis.