RecruitingPhase 2Drug trialIntralesional Injection of STS in Treatment of CalcinosisThe specific objective of this study is to perform a small, open-label study to assess the safety and efficacy of intralesional, subcutaneous injection of STS on calcinosis symptoms and lesion size in systemic sclerosis (SSc), mixed connective tissue disease (MCTD) and dermatomyositis (DM) patients. Injection will be guided by ultrasound, lesion size assessed by ultrasound, and symptom burden by patient-reported outcome measures.