One patient with dermatomyositis (DM) who developed spontaneous pneumomediastinum (SPnM) is described. A review of 15 previously reported cases shows that this is a complication of DM but not of polymyositis. It occurs in young patients with recent onset of disease characterized by cutaneous vasculopathy, and patients treated with immunosuppressive drugs have, in general, better outcomes. We suggest that the onset of SPnM in DM patients must alert to possible vasculitic activity and that immunosuppressive agents with progressive tapering of corticosteroids are part of the most reasonable approach in these cases.