Background
- Extraskeletal myxoid chondrosarcoma (EMC) is a rare soft tissue sarcoma defined by NR4A3 gene fusions.
- The most common partner is EWSR1, with less frequent fusions involving TAF15, TCF12, TFG, PGR, and SMARCA2.
- Although EMC may initially follow an indolent course, nearly half of patients ultimately develop metastases, and a subset experiences early recurrence or disease-related death.
- Morphologic grading provides limited prognostic value, and the clinical significance of non-EWSR1 fusion partners remains uncertain.
- These observations highlight the need to identify secondary genetic alterations that may explain the clinical heterogeneity of EMC.