MalignantSoft tissue
Extraskeletal Myxoid Chondrosarcoma
Synonyms: EMC, chordoid sarcoma
NR4A3 rearrangement is pathognomonic
Quick Facts
Behaviour
Malignant
Category
Soft tissue
Grade
Variable
Synonyms
- EMC
- chordoid sarcoma
Category
Soft tissue
Behaviour
Malignant
Grade
Variable
Gender
Male
Tissue of Origin
Cartilage
Epidemiology
- Rare soft tissue sarcoma with uncertain cartilaginous differentiation
- Middle-aged to older adults (median 50 years)
- Male predominance
- Deep soft tissue of extremities
Clinical Features
- Slowly growing deep soft tissue mass
- Often large at presentation
- Extremity or limb girdle
- Indolent but persistent course
Location
- Extremities (thigh most common)
- Limb girdle (hip, shoulder)
- Retroperitoneum
Imaging
- MRI: large lobulated soft tissue mass
- Heterogeneous signal with gelatinous/myxoid areas
- Often very large
Pathology
- Cords and chains of cells in abundant myxoid stroma
- NR4A3 (TEC) rearrangement - pathognomonic
- EWSR1-NR4A3 or TAF15-NR4A3 fusion
Genetics
- EWSR1-NR4A3 (most common)
- TAF15-NR4A3
- TCF12-NR4A3
Treatment
- Wide surgical excision
- Radiotherapy for positive margins
- Chemotherapy modest efficacy
- Indolent - long survival even with metastases
Prognosis
- Indolent course but high late metastasis (lungs)
- 5-year survival 80-90%; 10-year drops to 50%
- Late recurrence after >10 years common
Key Points
- NR4A3 rearrangement is pathognomonic
- Indolent course - long survival even with metastases
- Late metastasis - long-term surveillance essential
- Large deep thigh/limb girdle tumours
Workup - Blood Tests
FBC, LFTs
Workup - Local Imaging
- MRI primary site
- CT chest/abdomen/pelvis
Workup - Biopsy
- Core needle biopsy
- NR4A3 FISH or RNA sequencing
Workup - Staging
- CT chest/abdomen/pelvis
- PET-CT
Medical disclaimer
The content on Sarcopedia is for educational and informational purposes only and does not constitute medical advice. It is not intended to be a substitute for professional medical diagnosis or treatment. Always consult with a qualified physician regarding any health concerns or before starting any new treatment. Reliance on any information provided on this site is solely at your own risk.