Dysplasia epiphysealis hemimelica (DEH) is a rare skeletal dysplasia with epiphyseal involvement first described by Mouchet and Belot in 1926. Lower extremity involvement is common and might involve a single or multiple epiphyses in the affected extremity. We report an unusual case of involvement of the tibial tubercle in a girl aged 4 years 8 months, and we present the clinical, radiographic and pathologic findings. We discuss the role of MRI in the diagnosis and treatment plan.