Metachondromatosis.

OBJECTIVES: To draw attention to metachondromatosis, which may be misdiagnosed as multiple osteochondromatosis, and to point out several findings that have not been emphasized in previous reports. PATIENTS AND
METHOD: The authors reviewed the relevant clinical and detailed radiographic findings for five patients from different countries, who underwent imaging at various ages during childhood.
RESULTS: Deformities resembling exostoses and punctate calcification were distinctive and represent previously unemphasized features of vertebral involvement in metachondromatosis. Widespread metaphyseal changes were best seen in the femoral necks, which were broad and showed prominent cartilage columns in all of the patients. Flattening of the femoral heads was observed in three patients; in one of these the flattening progressed to epiphyseal necrosis and coxa magna. In one patient the hands and feet showed no enchondromatous involvement.
CONCLUSION: Metachondromatosis is a generalized bone dysplasia predominantly affecting the tubular bones and, to a lesser degree, flat bones and the vertebral column. Significant complications may include avascular necrosis of the femoral head and progressive deformity of the small joints due to expanding local exostoses. The typical involvement of the hands and the feet may not always be seen.