Enchondromas are benign cartilaginous neoplasms that are usually solitary lesions in intramedullary bone

When multiple enchondromas coexist, the diagnosis of enchondromatosis should be considered.

Multiple enchondromas may occur in 3 distinct disorders:

Ollier disease is a nonhereditary disorder characterized by multiple enchondromas with a predilection for unilateral distribution. The enchondromas can grow large and can be disfiguring.

Maffucci syndrome is nonhereditary and is less common than Ollier disease. This syndrome results in multiple hemangiomas in addition to enchondromas.

Metachondromatosis consists of multiple enchondromas and osteochondromas. Of the 3 disorders, metachondromatosis is the only one that is hereditary, which is by autosomal dominant transmission.

Solitary enchondromas most often are discovered in those aged 20-40 years. Ollier disease is usually detected in those aged 0-10 years.Enchondromas account for 12-14% of benign bone neoplasms and 3-10% of osseous neoplasms in general.

 

They have a predilection for the small bones of the hands and feet, where most occur. Of these, half are in the proximal phalanx, followed in frequency by the metacarpal and middle phalanx and, lastly, by the distal phalanges and carpus. Other locations are the shoulder, pelvis, and long bones. Enchondromas tend to occupy the diaphyseal region in the short tubular bones and the metaphyseal region in the longer bones.

When patients have pain and/or rapid growth of the lesion, malignant transformation should be suspected, even in the absence of suggestive radiographic findings.

Primary clinical complications include pathologic fracture and malignant transformation, which may be concomitant. In particular, pathologic fracture does not imply malignant transformation in the hands and feet, in which endosteal scalloping and cortical thinning may be extensive without malignant transformation.

Radiographic features are,

    Short bones: radiolucent lesion.

    Long bones: chondroid calcification (rings, arcs and popcorn type)

    Scalloped inner cortical margin.

    Expansion of cortex without cortical break.

    No periosteal reaction or soft tissue mass. Cortical break or soft tissue mass suggests malignant transformation