Dysplasia Epiphysealis Hemimelica

Dysplasia epiphysealis hemimelica (DEH), also known as Trevor-Fairbank disease or Trevor disease, refers to an osteochondroma arising from an epiphysis or sesamoid, tarsal or carpal bone. It is thought that there is abnormal cartilage proliferation with associated enchondral ossification.

Dysplasia epiphysealis hemimelica is almost always seen in the lower extremity. Upper extremity involvement has been reported, but is thought to be extremely rare. "Hemimelia" refers to the tendency of dysplasia epiphysealis hemimelica to involve either the medial (more common) or lateral aspect of the ossification center of a single extremity. Bilateral involvement has been reported, but is thought to be extremely rare.

Dysplasia epiphysealis hemimelica may is classified into

• Localized type: Affects a single bone.
• Classic type: 2/3 of cases. Affects more than one area in a single lower extremity.
• Generalized (severe) type: An entire lower limb is involved.

Dysplasia epiphysealis hemimelica presents between the ages of 2 and 14 years, and is three times more common in boys. The most common sites are the distal femur > proximal tibia > talus > tarsal navicular > first cuneiform.

Radiolographs and CT reveal a single or multiple irregular mass(es) with focal ossification arising from one side of the affected epiphysis or sesamoid bone. These lesions enlarge with skeletal growth and may ossify and become confluent with the underlying bone.

Dysplasia epiphysealis hemimelica may result in the following:

• Joint deformity
• Premature closure of the physis with deformity and limb length discrepancy
• Early secondary osteoarthritis from articular surface irregularity
• Undertubulation of bone from secondary involvement of the metaphysis

Differential Diagnosis

• Myositis ossificans
• Infection
• Chronic infantile neurologic, cutaneous, and articular (CINCA) syndrome
• Tumoral calcinosis
• Synovial osteochondromatosis
• Vascular calcifications
• Parasitic calcifications

References

Araujo CR, et al. Best Cases from the AFIP: Dysplasia Epiphysealis Hemimelica of the Patella. RadioGraphics 2006 26:581-586.