A Case of Anti-NXP2 Antibody-positive Juvenile Dermatomyositis with Characteristic Fascial Thickening on Muscle Ultrasound and Improvement with Immunotherapy.

Abstract

We herein report a 12-year-old boy who presented with a fever, erythematous rash on the cheeks, back pain, and dysphagia. Blood tests revealed increased creatine kinase levels, and muscle ultrasonography (MUS) revealed characteristic fascial thickening in the lumbar paraspinal muscles, where myalgia was prominent. Sarcoplasmic expression of myxovirus-resistant protein A on a muscle biopsy and the presence of anti-nuclear matrix protein 2 (NXP2) antibodies confirmed the diagnosis of dermatomyositis. Prednisolone and intravenous immunoglobulin therapy improved the clinical and laboratory parameters as well as fascial thickening. MUS is useful for evaluating fasciitis associated with anti-NXP2 autoantibodies and monitoring therapeutic efficacy.

• Authors: Koji Fukushima, Takeshi Yoshida, Hiroki Yamazaki, Naoko Takamatsu, Takashi Nagai, Yusuke Osaki, Masafumi Harada, Ichizo Nishino, Naoko Okiyama, Kazuma Sugie, Yuishin Izumi
• Journal: Internal medicine (Tokyo, Japan) (Intern Med) (Nov 06 2023) ISSN: 1349-7235 [Electronic] Japan
• PMID: 37926535 (Publication Type: Journal Article)