Anti-Melanoma Differentiation-Associated Gene 5 Dermatomyositis With Rapidly Progressive Interstitial Lung Disease Complicated by Pneumothorax, Pneumomediastinum, and Subcutaneous Emphysema: Clinical Course Compared With Reported Cases Worldwide.

Anti-melanoma differentiation-associated gene 5 (anti-MDA5) dermatomyositis (DM) represents a rare but clinically distinct subtype of idiopathic inflammatory myopathy. This condition is characterized by pathognomonic cutaneous manifestations, minimal muscle involvement, and an exceptionally high propensity for developing rapidly progressive interstitial lung disease (RP-ILD). We report a 49-year-old woman who presented with anti-MDA5 dermatomyositis complicated by RP-ILD and multiple severe thoracic complications, including recurrent pneumothorax, pneumomediastinum, and subcutaneous emphysema. Despite aggressive multimodal immunosuppressive therapy including high-dose corticosteroids, azathioprine, and mycophenolate mofetil (MMF), her clinical condition deteriorated rapidly. The patient required multiple interventions, including repeated chest tube placements, talc pleurodesis, and mechanical ventilation. Lung transplantation evaluation deemed her unsuitable for surgery, and she ultimately succumbed to hypoxic-hypercapnic respiratory failure within six months of initial presentation. This case underscores the aggressive natural history and guarded prognosis associated with anti-MDA5 dermatomyositis when complicated by RP-ILD and thoracic manifestations. The early recognition, prompt diagnosis, and immediate initiation of combination immunosuppressive therapy are paramount, although standardized treatment protocols remain elusive. Urgent research initiatives are needed to establish evidence-based therapeutic guidelines and improve patient outcomes in this challenging clinical entity.