Maffucci syndrome is a sporadic condition, in which osteochondromatosis (mostly enchondromas) and hemangiomas occur (in the related Ollier syndrome only cartilaginous Tumours occur). Cavernous or capillary hemangiomas, phlebectasia, and lymphangiomas may develop and can be disfiguring. The dyschondroplasia may result in shortening of bones, fractures, and deformities from enchondromas. Many mesenchymal neoplasias may occur, possibly in 15–30 % of cases (Harris 1990; Albrechts and Rapini 1995). Chondrosarcoma is the most common malignancy to develop in this condition (75 %), but fibrosarcoma, angiosarcoma, osteosarcoma, ovarian granulosa cell Tumours or teratomas, acute myeloid leukemia, and gliomas have been reported (Sun et al. 1985; Schwartz et al. 1987; Christian and Ballon 1990; Chang and Prados 1994). Multiple primary Tumours may develop (Loewinger et al. 1977; Amary et al. 2011).
Maffucci syndrome was long suspected to result from constitutional mosaicism, and most cases are now known to be caused by mosaicism for specific missense mutations in isocitrate dehydrogenase 1 (IDH1) or in IDH2 (most commonly p.Arg132Cys substitution in IDH1) (Amary et al. 2011; Pansuriya et al. 2011).