Calcinosis Universalis: An Atypical Presentation of Mi-2 Positive Juvenile Dermatomyositis - A Case-Based Review

Juvenile Dermatomyositis (JDM) is a systemic autoimmune disease in children, characterised by skin and muscle inflammation, with incidence of 1.6 to 4 cases per million children annually. Calcinosis, affecting 20% to 70% of JDM patients, can lead to significant morbidity. The association of calcinosis with anti-Mi-2 antibodies is rare and complicates management. We present a rare case of a 12-year-old girl diagnosed with JDM, extensive calcinosis, and positive anti-Mi-2 antibodies. The patient exhibited significant muscle weakness, skin manifestations, and painful calcinosis leading to contractures. Initial management included tofacitinib and intravenous pamidronate, resulting in no new calcinosis formation. A comprehensive review of existing literature highlights the rarity of calcinosis in anti-Mi-2 positive patients. While traditional treatments have shown variable effectiveness, emerging therapies like JAK (Janus Kinase) inhibitors may offer new avenues for management. The literature underscores the need for personalised treatment strategies given the atypical presentations and outcomes. This case adds to the limited documentation of calcinosis in JDM with anti-Mi-2 antibodies, emphasising the need for increased awareness and research. Personalised treatment approaches are crucial, and future studies should focus on larger datasets and emerging therapeutic modalities to optimise management and improve patient outcomes.