Spontaneous regression of metastatic disease after palliative debulking surgery for heavily pre-treated extraskeletal myxoid chondrosarcoma: A case report

Spontaneous regression of metastatic disease in the setting of advanced cancer is a poorly understood clinical phenomenon which occurs infrequently across all tumour types but exceptionally rarely in soft tissue sarcomas. Extraskeletal myxoid chondrosarcoma (EMC) is a rare subtype of soft tissue sarcoma that is poorly responsive to systemic treatment, providing limited options to patients with metastatic disease. We report spontaneous regression of lung metastases in a patient with EMC after re-resection of the primary tumour, which was performed with palliative intent for symptom control after multiple lines of systemic treatment. The patient has remained disease-free and is now more than 5 years post-surgery. To our knowledge, this is the first described case of spontaneous regression of metastatic disease following resection of a primary tumour in a patient with EMC.