Dysplasia Epiphysealis Hemimelica, Growth Disorder

Dysplasia epiphysealis hemimelica (DEH) is a rare developmental disorder affecting the ends of a long bone (epiphyses). DEH is not a cancerous disorder. The lesion is continuously increases in size until skeletal maturity. If left untreated, the condition involving the weight-bearing surface of the joint, can cause pain and joint degeneration resulting in partial or complete incapacity of its use.

The causes of DEH are unknown, although error in epiphyseal development that affects the limb buds during early fetal life has been suggested as one of the possible causes. DEH most commonly occurs around the knee and ankle bones. It is seen in the first year of life as knee or ankle deformity, painful gait and limp, swelling or a mass on one side of a joint, limitation of motion, muscle wasting, and, occasionally, recurrent locking of the joint.

The disorder is seen both in humans and animals. It has been described in Boxer dogs.

References:
1. Dysplasia epiphysealis hemimelica in a Boxer puppy. Vignoli M, Sarli G, Rossi F, Terragni R, Pozzi L.