Spontaneous pneumomediastinum in a dermatomyositis patient with anti‐melanoma differentiation‐associated gene‐5 antibody and interstitial lung disease despite an initial response to immunosuppressant

We report a 24‐year‐old man with anti‐melanoma differentiation‐associated gene‐5 ( MDA 5) antibody‐positive dermatomyositis ( DM ) and interstitial lung disease ( ILD ) who developed spontaneous pneumomediastinum. By comparing serial thoracic high‐resolution computed tomography scans, we demonstrated the distinct time course showing a paradoxical occurrence of pneumomediastinum despite a radiological improvement of ILD . Our case shows that pneumomediastinum in DM can occur regardless of associated ILD and it is a serious complication that should be considered in DM patients presenting with pulmonary manifestations. Cutaneous vasculopathy may be associated with pneumomediastinum and could potentially be a useful indicator of future disease.