In this study, our aim was to evaluate the effect of IDH mutations on outcome, and on histone modifications (H3K4me3, H3K9me3 and H3K27me3), DNA modifications (5-hmC and 5-mC), chromatin remodeling (ATRX), and subcellular localization of TET1 in a cohort of enchondromas and central chondrosarcomas for which we determined mutation status of IDH, SDH and FH. The gene discussed is IDH1; the disease is chondrosarcoma.