Discussion: Dysplasia epiphysealis hemimelica (DEH) or Trevor's disease is a rare developmental disorder affecting the epiphyses in young children.
DEH is thought to be a variant of osteochondroma arising within a joint.
DEH is a benign disorder, and no cases of malignant transformation have been reported.
Microscopically: The histologic appearance of the lesion is that of a well-defined cartilage cap over projecting bone that is contiguous with the underlying normal bone. It is indistinguishable from that of an osteochondroma.
The basic pathologic process appears to be abnormal cartilage proliferation in an epiphysis with associated endochondral ossification before complete ossification. A cleavage area of cartilage is present between the ossification center in the lesion and that of the epiphysis.
Frequency: The incidence of DEH has been estimated at 1 case per million population.
No race predilection is known to exist.
DEH is most commonly found in males, with a male-to-female ratio of 3:1.
It usually manifests in childhood and early adolescence.
Etiology: The etiology is unknown; the disease does not appear to be genetically transmitted.
Clinical: Most patients present with painless swelling or a mass on one side of the joint, limitation of motion, and occasionally, recurrent locking of the joint.
DEH most commonly occurs around the knee, talus, and tarsal navicular and first cuneiform joints.
The medial side of the epiphysis is most commonly affected.
Plain radiography may reveal early focal calcification of the affected site with later appearance of an irregular bony enlargement, which becomes fused to the affected epiphysis.
Therapy:
Supportive joint care, consisting of short-term splinting of the joint, may be of benefit.
Most of the reported cases of DEH in the literature have been treated surgically, in the form of excision of the mass while preserving the integrity of the affected joint as much as possible and correction of angular deformity.
Complications:
Complications include recurrence of the angular deformity after the corrective osteotomy, degenerative osteoarthritis, fixed deformity, leg-length discrepancy, and loose bodies.
Differential Diagnosis incudes osteochondroma, chondroblastoma, and enchondroma.
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TREVOR'S DISEASE
