CDKN2A and chondrogenic neoplasm: This concurs with previously published data from smaller cohorts which report that loss of p16/CDKN2A is rarely present in enchondromas and low grade chondrosarcomas, whereas IDH1 and IDH2 mutations are found in tumours of all grades of chondrosarcomas and in benign conventional central cartilaginous tumours [12, 13].