Rapidly Progressive Interstitial Lung Disease With Pneumothorax and Pneumomediastinum Secondary to Amyopathic Dermatomyositis.

Amyopathic dermatomyositis is a rare form of dermatomyositis characterized by cutaneous lesions without clinical, biological, or histological muscular involvement. Pulmonary complications associated with this condition are diffuse interstitial lung disease (ILD), pneumomediastinum, and spontaneous pneumothorax. The form associated with anti-melanoma differentiation-associated protein 5 (anti-MDA-5) antibodies is reputed to have a poor prognosis and is responsible for ILD which can rapidly progress to fatal respiratory failure. Treatment of amyopathic dermatomyositis is essentially based on corticosteroid therapy and immunosuppressants. We present the case of a 42-year-old patient followed for three months for diffuse ILD. The patient was hospitalized for respiratory distress secondary to an aggravation of ILD with pneumomediastinum and pneumothorax. The patient also presented with cutaneous lesions identified as Gottron's papules. The patient was diagnosed with amyopathic dermatomyositis positive for anti-MDA-5 antibodies.