Key Findings
- Extraskeletal myxoid chondrosarcoma (EMC) is a rare sarcoma defined by NR4A3 fusions, most commonly with EWSR1.
- Secondary genetic alterations were detected in over half of informative EMC cases and were significantly enriched in tumors with non EWSR1 fusion partners.
- These findings suggest that secondary alterations in advanced-stage EMC may contribute to the disease’s clinical and genomic heterogeneity.