The incidence of this Tumours increases with increasing age. Chondrosarcoma is described as a complication of multiple enchondromatosis (Ollier disease), inherited multiple exostoses (diaphysial achlasis),
Maffucci syndrome (Hecht et al. 1997), and other conditions in which exostoses occur. The incidence of malignancy in these syndromes has been assessed as 18 % (Sun et al. 1985). Two groups have recently reported that somatic mosaic mutations in IDH1 and IDH2 are the predominant cause of both Ollier disease and Maffucci syndrome (Pansuriya et al. 2011; Amary et al. 2011).
Multiple enchondromatosis (Ollier disease) is usually sporadic, although several families with affected siblings have been described. Deformities, particularly of the long bones, develop because of the enchondromas, resulting in asymmetrical, bilateral limb shortening, bowing, or deformation. The enchondromas tend to grow until adolescent growth is over. Sarcomatous degeneration (chondrosarcoma) can occur in the lesions in adult life, and intracranial gliomas (Chang and Prados 1994) and ovarian juvenile granulosa cell Tumours and precocious puberty have also been described in this condition (Tamimi and Bolen 1984).
Maffucci syndrome, characterized by multiple enchondromas and subcutaneous hemangiomas, is associated with a high risk of malignant transformation, a risk of 30 % for chondrosarcomas and other malignancies being reported (Albrechts and Rapini 1995; Kaplan et al. 1993). Intracranial chordoma has also been reported in this syndrome (Nakayama et al. 1994). There was a suggestion that a single germline mutation in parathyroid hormone-related protein (PTHR1), c.448CT, resulting in R105C could be an important cause of endochrondromatosis (Hopyan et al. 2002), but a subsequent study did not find any mutations in PTHR1 in patients with enchondromatosis (Rozeman et al. 2004).
Hereditary multiple exostoses, associated with germline mutations in the EXT2 gene, predispose to familial chondrosarcoma (Hecht et al. 1997), and loss of heterozygosity is seen in the Tumours in the region of chromosome 11 where EXT2 maps.