皮質血管虚血：皮下結節を有する患者における隠れた全身性疾患の手がかり

Dermatomyositis most commonly presents with characteristic rash or proximal muscle weakness; however, specific autoantibody subsets can produce markedly atypical phenotypes. Anti-NXP2 dermatomyositis is clinically significant for its strong association with malignancy, extensive calcinosis, and presentations that may be amyopathic or minimally symptomatic. We report a rare case of anti-NXP2-positive dermatomyositis manifesting without classical cutaneous or muscular features, instead presenting with acute limb ischemia and long-standing subcutaneous nodules. Amyopathic anti-NXP2 disease is uncommon in adults, accounting for a small minority of dermatomyositis cases, making this presentation particularly unusual. Imaging demonstrated diffuse subcutaneous and intramuscular calcifications with large-vessel disease, while serologic testing confirmed anti-NXP2 antibodies. Following revascularization and multidisciplinary evaluation, limb perfusion and wound healing improved for this case. Amyopathic presentations of anti-NXP2 dermatomyositis are rare, reported in only a small subset of patients, highlighting the atypical nature of this case. This case underscores the need to consider autoimmune myositis in patients presenting with calcinosis cutis and ischemic changes, as recognition of anti-NXP2 dermatomyositis is essential for early diagnosis, multidisciplinary management, guidance of oncologic surveillance, and prevention of irreversible vascular outcomes.