Other Rare Benign Lesions

Abstract

Dysplasia epiphysealis hemimelica, also called Trevor disease or Fairbank disease, is a rare nonfamilial disease of unknown etiology. It presents in early childhood between the ages of 3 and 15 years with osteochondroma-like swelling close to a joint, a limited range of movement, and occasional “locking” of the involved joint. A cartilaginous lesion that continues to grow and undergo endochondral ossification until skeletal maturity is reached and generally requires surgical treatment causes the swelling. The majority of children have more than one lesion affecting a single limb, usually a lower limb. Radiologically and macroscopically, the features of dysplasia epiphysealis hemimelica overlap with those of osteochondromas. Histologically, dysplasia epiphysealis hemimelica is composed of multiple nodules of cartilage with centers of active endochondral ossification in the epiphysis functioning as accessory secondary ossification centers. By 3–4 years of age, most of the nodules have fused with epiphysis, and the accessory ossification centers have disappeared. The cartilage cap contains chondrocytes arranged in a fibrillar matrix in a somewhat disorganized manner compared with the surrounding normal cartilage. The differential diagnosis includes enchondroma, synovial chondromatosis, and chondrosarcoma. Radiologic correlation is required for diagnosis.