Excellent Response and Persistent Local Control of Metastatic Extraskeletal Myxoid Chondrosarcoma Repeatedly Treated with Surgical Excision or Stereotactic Radiotherapy Alone: A Case Report

Introduction: Extraskeletal myxoid chondrosarcoma (EMC) is an extremely rare mesenchymal tumor, accounting for less than 3% of soft tissue sarcomas. Even though metastatic rate after radical surgery in EMC can reach 50%, prolonged survival is common even in the presence of metastatic disease. Prospective studies evaluating the role of trabectedin, antiangiogenic agents, and immunotherapy are ongoing to assess the best systemic treatment. Case Presentation: We report the case of a young Sri Lankan woman who initially underwent neoadjuvant radiotherapy and surgery for a mass of the right thigh, then experienced local relapse, managed with chemotherapy and surgery again, and finally was diagnosed with distant progression. All metastatic sites of EMC were treated with either surgical excision or stereotactic ablative radiotherapy alone in three different occasions, showing complete or major response. Conclusion: This individualized approach enabled prolonged systemic therapy-free intervals with minimal toxicity, so could be considered in selected patients.