extraskeletal myxoid chondrosarcoma
extraskeletal myxoid chondrosarcoma
A phenotypically and genotypically distinct mesenchymal malignancy with tumour-specific fusion genes, which affects older adults and represents 2.5% of soft tissue sarcomas. ESMCS differs from the primary skeletal chondrosarcoma given the myxoid changes, and is classified as a tumour of uncertain differentiation. It arises in the deep soft tissues of the leg in 75% of cases (thigh, popliteal fossa and buttock). 80% occur in the proximal extremities and limb girdles; 20% in the trunk.Extraskeletal myxoid chondrosarcoma
• Cellular variant without myxoid matrix;
• Classical variant;
• Dedifferentiated type;
• Epithelioid type;
• Rhabdoid type;
• Small cell type.
Imaging
Cortical erosion and buttressing.
Epidemiology
Male:female ratio, 2:1.
DiffDx
Intramuscular myxoma, myxoid liposarcoma, fibromyxoid sarcoma, myxoid embryonal rhabdomyosarcoma.
Differentiation
Cartilaginous, neuroendocrine, neural.
Management
Surgical excision; adjuvant chemotherapy if nodal spread or metastasis.
Prognosis
Frequent local recurrence; late metastases; 5-year, 10-year, 15-year survival, 90%, 70%, 60% respectively; continued follow-up is necessary.