SOX9 and mesenchymal chondrosarcoma: A valuable marker, as SOX9, shows nuclear positivity inboth areas, but mainly on the immature component (chondroprogenitor cell’sphenotype) of mesenchymal chondrosarcoma, differentiating it from other small cell tumors.12 However, it is not totally specific, because SOX9 can be found in anyneoplasm of cartilaginous lineage.