Anti‐melanoma differentiation‐associated gene 5 antibody–positive dermatomyositis with possible complication of thrombotic microangiopathy

This case study illustrates a 63‐year‐old Japanese woman who presented with anti‐melanoma differentiation‐associated gene 5 antibody–positive dermatomyositis. She was administered a therapeutic regimen consisting of corticosteroids, tacrolimus, and cyclophosphamide. However, after a month of treatment, symptoms of confusion and depressive tendencies emerged, followed by the manifestation of hematuria, thrombocytopenia, and fragmented erythrocytes. A disintegrin‐like and metalloprotease with thrombospondin type 1 motifs 13 activity was 45%. Thrombotic microangiopathy was contemplated, yet a definitive diagnosis remained elusive. She died 2 months after admission. Although the occurrence of thrombotic microangiopathy in patients with dermatomyositis is rare, the prognosis is poor, emphasizing the importance of prompt diagnosis and treatment.