Enchondroma is a benign cartilaginous neoplasm in the medullary cavity. Most echondromas are
asymptomatic but may present as pathological fractures. Peak age is 10-30 years.
- Tubular bones (hand, foot): 50%
- Femur, tibia, humerus
- Lytic lesion in bones of the hand or foot
- Chondroid calcifications: rings and arcs pattern ("O" and "C")
- Scalloped endosteum
- Expansion of cortex but no cortical breakthrough unless fractured
- No periosteal reaction or soft tissue mass
- In the absence of a fracture, a painful enchondroma is considered malignant until proven otherwise.
- Malignant transformation occurs but is rare.
Enchondromatosis (Ollier disease)
Ollier disease is a nonhereditary abnormality in which multiple enchondromas are present. Many lesions become stable at puberty. Risk of malignant transformation to chondrosarcoma is 25%.
- Multiple radiolucent expansile masses in hand and feet
- Hand and foot deformity
- Tendency for unilaterality
Maffucci syndrome comprises enchondromatosis and multiple soft tissue hemangiomas. Unilateral involvement of hands and feet. Malignant transformation is much more common than in Ollier's disease.