Extraskeletal myxoid chondrosarcoma (EMC) is a unique, rare soft-tissue tumor with prominent myxoid morphology. The tumor most commonly develops in deep parts of the proximal extremities and limb girdles in middle-aged adults, and there is a predilection for male patients. Currently, a chromosomal translocation t(9;22)(q22;q12) and the resultant fusion gene, EWSR1-NR4A3, has been defined in approximately 75% of EMC. More recently, another fusion gene, TAF15-NR4A3, resulting from t(9;17)(q22;q11.2), has been identified. The abnormal proteins resulting from these fusion genes aberrantly affect gene transcription and cellular signaling pathways thought to be responsible for initiating sarcoma formation.
