A 5-year-old Romanian boy presented with heliotrope erythema, periungual telangiectasia, Gottron's papules, discrete calcium deposits over extensor surfaces and severe myositis. Whole-body magnetic resonance revealed bilateral generalized myositis and he was diagnosed with juvenile dermatomyositis. Esophagogram, cardiac and pulmonary evaluation and myositis-specific autoantibodies were normal. He received corticosteroids, methotrexate, immunoglobulins, and hydroxychloroquine for 5 months with significant improvement. His family, however, was reluctant to maintain the therapy and returned to Romania, stopping all medications. For the next 8 months he did not receive any treatment, developing failure to thrive, worsening proximal myopathy, generalized deposition of calcium, and significant joint contractures that led to a complete loss of autonomy. He was treated at a Romanian reference center with corticosteroids, mycophenolate, immunoglobulins and IV cyclophosphamide without improvement, moving back to Spain for therapy at the age of 7. Physical examination revealed severe weakness with diffuse hardening of skin and subcutaneous tissue, nodular deposits of calcium as well as significant collections of calcium over his joints with focal ulcerations and joint contractures that interfered with all daily activities (Figure 1). Diffuse calcification was observed in X-ray images.

He was hospitalized and systemic corticosteroids (intravenous methylprednisolone 30 mg/kg for 3 days followed by oral prednisone 60 mg/kg), immunoglobulins (2 g/kg monthly), subcutaneous methotrexate (15 mg per week), hydroxychloroquine (75 mg per day), tacrolimus (1.5 mg per day), intravenous pamidronate (1 mg/kg monthly), topical sodium metabisulfite over ulcerations and intensive physiotherapy were started. Tacrolimus was substituted by oral baricitinib (2 mg per day) after interferon signature revealed high expression of type 1 interferon and lack of improvement.

During the next months the patient's general condition, autonomy and muscle strength improved markedly, although it took 5 months to see evident clinical benefit. Creatinine kinase levels were over 600 U/L before starting baricitinib and normalized after 6 months of treatment. Calcium deposits progressively softened and articular balance increased significantly enabling him to ride his bicycle again. After 7 months, he continues with infusions of immunoglobulins and pamidronate, hydroxychloroquine, methotrexate and baricitinib with no adverse events.

Calcinosis associated with juvenile dermatomyositis (JDM) appears in up to 40% of the patients. Common complications include muscle atrophy, contractures, and ulceration. Rarely, calcinosis can progress to exoskeleton formation and is one of the most treatment-refractory complications. Calcinosis appears 1–3 years after disease onset and indicates persistent inflammatory activity. Risk factors include treatment delay, chronic persistent disease and positive NXP2 antibodies.¹

Treatment of calcinosis is challenging and frequently disappointing. Lack of strong evidence and difficulties regarding the evaluation of treatment response are additional pitfalls. The mainstay of treatment is to control the inflammation of the underlying dermatomyositis. If necessary, calcinosis-specific treatment options should be considered.²

Increasing evidence support the benefits of JAK inhibition in the treatment of dermatomyositis, especially in patients with high expression of type-1 interferons. Specific reports on the benefit in calcinosis are yet sparse and of uneven quality.³

Among the many and rather disappointing alternatives for managing calcinosis, at present bisphosphonates seem to be the best option, although improvement may have a delay of months to years.⁴ Intravenous pamidronate is the most frequently used, at one to three monthly intervals, which can be combined with immunoglobulins during hospitalization.

Topical sodium metabisulfite, a more stable derivate of thiosulphate, may be useful over superficial or ulcerated calcium deposits.⁵

In summary, severe deposits of calcium in the setting of JDM can be prevented with close follow-up for early escalation of dermatomyositis-specific treatment. The use of JAK inhibitors appears safe in pediatric population and its specific usefulness in dermatomyositis-related calcinosis, as in our case, seems promising. Furthermore, calcium-specific directed therapies, especially bisphosphonates, should also be considered. Multidisciplinary approach is mandatory and even though the outcome of these patients remains poor, positive results may appear after several months or up to years.

一名 5 岁的罗马尼亚男孩因鸡眼红斑、甲周毛细血管扩张、Gottron 丘疹、伸肌表面散在的钙沉积和严重的肌炎就诊。全身磁共振显示双侧全身性肌炎，诊断为幼年型皮肌炎。食管造影、心肺评估和肌炎特异性自身抗体均正常。他接受了 5 个月的皮质类固醇、甲氨蝶呤、免疫球蛋白和羟氯喹治疗，病情有了显着改善。然而，他的家人不愿意维持治疗并返回罗马尼亚，停止了所有药物治疗。在接下来的 8 个月里，他没有接受任何治疗，发育迟缓，近端肌病恶化，钙普遍沉积，严重的关节挛缩导致完全丧失自主权。他在罗马尼亚参考中心接受了皮质类固醇、霉酚酸酯、免疫球蛋白和静脉注射环磷酰胺的治疗，但没有改善，7 岁时回到西班牙接受治疗。身体检查显示严重虚弱，皮肤和皮下组织弥漫性硬化，结节状钙沉积以及关节处大量钙质积聚，并伴有局灶性溃疡和关节挛缩，影响了所有日常活动（图 1）。在 X 射线图像中观察到弥漫性钙化。身体检查显示严重虚弱，伴有皮肤和皮下组织弥漫性硬化、结节状钙质沉积以及关节处大量钙质聚集，伴有局灶性溃疡和关节挛缩，影响了所有日常活动（图 1）。在 X 射线图像中观察到弥漫性钙化。身体检查显示严重虚弱，伴有皮肤和皮下组织弥漫性硬化、结节状钙质沉积以及关节处大量钙质聚集，伴有局灶性溃疡和关节挛缩，影响了所有日常活动（图 1）。在 X 射线图像中观察到弥漫性钙化。

他住院并全身使用皮质类固醇（静脉注射甲泼尼龙 30 mg/kg，持续 3 天，然后口服泼尼松 60 mg/kg）、免疫球蛋白（每月 2 g/kg）、皮下注射甲氨蝶呤（每周 15 mg）、羟氯喹（每天 75 mg） )、他克莫司（每天 1.5 毫克）、静脉注射帕米膦酸盐（每月 1 毫克/千克）、局部焦亚硫酸钠治疗溃疡和强化理疗。在干扰素特征显示 1 型干扰素高表达且缺乏改善后，他克莫司被口服巴瑞克替尼（每天 2 毫克）替代。

在接下来的几个月里，尽管需要 5 个月的时间才能看到明显的临床益处，但患者的一般状况、自主性和肌肉力量都有显着改善。在开始巴瑞克替尼之前，肌酐激酶水平超过 600 U/L，并在治疗 6 个月后恢复正常。钙沉积物逐渐软化，关节平衡显着增加，使他能够再次骑自行车。7 个月后，他继续输注免疫球蛋白和帕米膦酸盐、羟氯喹、甲氨蝶呤和巴瑞克替尼，没有出现不良事件。

高达 40% 的患者出现与幼年型皮肌炎 (JDM) 相关的钙质沉着症。常见的并发症包括肌肉萎缩、挛缩和溃疡。钙质沉着症很少会发展为外骨骼形成，并且是最难治疗的并发症之一。钙质沉着症出现在疾病发作后 1-3 年，表明持续的炎症活动。危险因素包括治疗延误、慢性持续性疾病和 NXP2 抗体阳性。^1个

钙质沉着症的治疗具有挑战性且常常令人失望。缺乏强有力的证据和治疗反应评估方面的困难是额外的陷阱。主要的治疗方法是控制皮肌炎的炎症。如有必要，应考虑针对钙质沉着症的治疗方案。^2个

越来越多的证据支持 JAK 抑制在治疗皮肌炎方面的益处，尤其是在 1 型干扰素高表达的患者中。关于钙质沉着症获益的具体报告还很少，而且质量参差不齐。^3个

在控制钙质沉着症的许多令人失望的替代方案中，目前双膦酸盐似乎是最好的选择，尽管改善可能会延迟数月至数年。⁴静脉注射帕米膦酸盐最常用，间隔1-3个月一次，住院期间可与免疫球蛋白联合使用。

外用焦亚硫酸钠是一种更稳定的硫代硫酸盐衍生物，可能对浅表或溃疡性钙沉积物有用。^5个

总之，可以通过密切随访早期升级皮肌炎特异性治疗来预防 JDM 中的严重钙沉积。JAK 抑制剂在儿科人群中的使用似乎是安全的，并且它在皮肌炎相关钙质沉着症中的特殊用途，如我们的案例，似乎很有希望。此外，还应考虑钙特异性定向疗法，尤其是双膦酸盐。多学科方法是强制性的，即使这些患者的结果仍然很差，几个月或长达几年后可能会出现阳性结果。