Spontaneous pneumomediastinum has been described in patients with dermatomyositis (DM) and polymyositis (Korkmaz et al., Rheumatology 40:476-478, 2001; Maruoka et al., Mod Rheumatol 16:55-57, 2006; Kono et al., Ann Rheum Dis 59:372-376, 2000; Neves et al., Clin Rheumatol 26:105-107, 2007). Literature reviews suggest that this complication has a mortality of between 27% and 41% ( Kono et al., Ann Rheum Dis 59:372-376, 2000; Neves et al., Clin Rheumatol 26:105-107, 2007; Goff et al., Arthritis Rheum 61:108-118, 2009). This is the first report of rituximab being used successfully as part of the treatment for DM complicated by pneumomediastinum.