Melanoma Differentiation-associated Gene 5-Positive Rapidly Progressive Interstitial Lung Disease Successfully Treated with Tofacitinib.

Anti-melanoma differentiation-associated gene 5 (MDA-5) antibody-positive dermatomyositis is associated with rapidly progressive interstitial lung disease (RP-ILD). We encountered a man in his 40s who presented with a history of a fever and dry cough. Based on laboratory tests and computed tomography scans of his chest, he was diagnosed with anti-MDA5 antibody-positive dermatomyositis with RP-ILD refractory to antimicrobial agents. Although the patient was treated with glucocorticoids, calcineurin inhibitors, intravenous cyclophosphamide, and plasma exchange, ventilatory management was still required. The patient survived additional therapy with tofacitinib; however, he developed a catheter-related pulmonary embolism as a complication.