Patients are normal at birth and the syndrome manifests during childhood. The enchondromas affect the extremities and their distribution is asymmetrical. The most common sites of enchondromas are the metacarpal bones and phalanges of the hands. The feet are less commonly affected. Disfigurations of the extremities are a result. Pathological fractures can arise in affected
metaphyses and
diaphyses of the long bones and are common (26%). The risk for
sarcomatous degeneration of enchondromas, hemangiomas, or lymphangiomas is 15–30% in the setting of Maffucci syndrome. Maffucci syndrome is associated with a higher risk of CNS, pancreatic, and ovarian malignancies. Multiple enchondromas may present in three disorders:
Ollier disease, Maffucci syndrome, and
metachondromatosis. It is important to make the distinction between these diseases, particularly Ollier disease and Maffucci syndrome. Ollier disease is more common than Maffucci syndrome, and presents with multiple enchondromas often in a unilateral distribution. However, hemangiomas and lymphangiomas are not seen in Ollier disease. Metachondromatosis demonstrates autosomal-dominant transmission and presents with both multiple osteochondromas and enchondromas. It is associated with multiple
cavernous hemangioma and
phlebolith.
Lymphangiomas may also be apparent. ==Cause==