Definition
Enchondromas are benign, intramedullary, usually solitary cartilaginous neoplasms that predominantly grow in the metaphyseal portion of tubular bones. They arise from foci of displaced or remodeling cartilage of the growth plate. Chondrocytes start proliferating during childhood, leading to enlargement of the tumor. In adulthood, enchondromas usually stop growing but persist.
Multiple enchondromas (enchondromatosis) are typically seen in Ollier disease and Maffucci syndrome.
Ollier disease features multiple intraosseous enchondromas with variable numbers, sizes, and locations.
Maffucci syndrome is characterized by multiple enchondromas and extraosseous hemangiomas.
Ollier disease and Maffucci syndrome are typically not inherited; however, there are exceedingly rare subtypes of enchondromatosis that show autosomal dominant and recessive inheritance.
Enchondromas are relatively common lesions, accounting for up to a quarter of benign bone tumors and roughly 10% of all bone tumors. They may present at any decade of life, but more than half of cases occur between the second and fourth decades of life with an equal sex distribution.