Tohoku J. Exp. Med., 2022 April, 256(4)

Anti-Mi-2 and Anti-TIF1-γ Double-Positive Juvenile Dermatomyositis Treated under Diagnosis of Chronic Eczema: A Case Report

Shuhei Yoshida,¹ Haruki Matsumoto,¹ Yuya Fujita,¹ Kohei Yokose,¹ Jumpei Temmoku,¹ Naoki Matsuoka,¹ Makiko Yashiro-Furuya,¹ Tomoyuki Asano,¹ Shuzo Sato,¹ Eiji Suzuki,² Toru Yago,¹ Takae Yaguchi,³ Tetsuro Aita,³ Misaki Kusano,⁴ Toshiyuki Yamamoto,⁴ Hiroshi Watanabe¹ and Kiyoshi Migita¹

¹Department of Rheumatology, Fukushima Medical University School of Medicine, Fukushima, Fukushima, Japan
²Department of Rheumatology, Ohta Nishinouchi General Hospital Foundation, Koriyama, Fukushima, Japan
³Department of General Internal Medicine, Fukushima Medical University School of Medicine, Fukushima, Fukushima, Japan
⁴Department of Dermatology, Fukushima Medical University School of Medicine, Fukushima, Fukushima, Japan

Myositis-specific autoantibodies are relevant factors that define the disease phenotype of dermatomyositis (DM). Anti-Mi-2 antibody-positive DM patients may present with the typical skin lesions and prominent myositis. On the other hand, adult DM patients with anti-TIF-γ antibody seem to be associated with internal malignancy. Here, we report a rare case of juvenile dermatomyositis (JDM) exhibiting anti-Mi-2 and antitranscriptional intermediary factor-1 gamma (TIF1-γ ) antibodies, with no internal malignancy. A 16-year-old female Japanese patient under treatment with a 2-year history of chronic eczematous lesions was admitted to our department with elevated levels of muscle enzymes. Characteristic skin changes, such as Gottron's papules of the hand, heliotrope rash of the eyelids, and poikiloderma-like legions and diffuse pigmentation on the back, were observed. Histologically, the patient’s skin was characterized by the presence of lymphocytic vascular inflammation and endothelial swelling, which are consistent with DM. Severe symmetric proximal muscle weakness, elevated serum muscle enzymes and the presence of anti-TIF1-γ and Mi-2 antibodies were noted. The diagnosis of JDM was made according to the European League Against Rheumatism (EULAR) diagnostic criteria. A high dose of corticosteroids and following intravenous cyclophosphamide treatment (750 mg three times) resulted in an improvement in clinical manifestations and functional outcomes, and recurrence did not occur. Estimation of autoantibodies may serve as an ancillary tool in delineating and defining distinct clinical phenotypes in JDM.

Keywords —— anti-Mi-2 antibodies; anti-TIF1-γ dermatitis; Gottron's sign; juvenile dermatomyositis

© 2022 Tohoku University Medical Press

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Tohoku J. Exp. Med 2022, 256, 303-308.

Correspondence: Kiyoshi Migita, M.D., Ph.D., Department of Rheumatology, Fukushima Medical University School of Medicine, 1 Hikarigaoka, Fukushima, Fukushima 960-1295, Japan.

e-mail: migita@fmu.ac.jp