IDH2 and chondrosarcoma: The most common genetic alteration in central conventional chondrosarcoma is the hotspot mutation affecting the arginine residues encoded by the isocitrate dehydrogenase 1 and -2 (IDH1 or IDH2, collectively referred to as IDH) genes (R132 and R140/R172, respectively), occurring in ~50% of the cases [5,6].