Hemimelic epiphyseal dysplasia: a case report.

Hemimelic epiphyseal dysplasia HED also known as Trevor's disease is a rare pathology, characterized by a developmental disorder of an internal or external half of one or more epiphyses of a limb, mainly the lower limb, and/or of the short tarsal bones in children and young adolescents, with a male predominance. Its etiology remains unclear. Its clinical symptomatology is variable, ranging from asymptomatic involvement to orthopedic complications such as limb length inequality. As the clinic is non-specific, radiological assessment is the essential diagnostic tool for Trevor's disease, including standard radiography, MRI, CT, and possibly biopsy in some cases. The radio clinical signs make it possible to establish the diagnosis, even if it remains difficult because of the rarity of the disease and the presence of multiple differential diagnoses which are often better known such as osteochondroma and exostosis. After diagnostic confirmation, the therapeutic decision remains debated, ranging from simple observation to surgical excision. The prognosis of HED remains good, given the absence of the risk of malignant transformation. Post-therapeutic complications are dominated by recurrence or the appearance of secondary osteoarthritis. Objective: This clinical case challenges us to keep in mind the hemimelic epiphyseal dysplasia (HED) in front of a mass that originates at the level of the internal or external half of one or more epiphyses in children.