Case report Dysplasia epiphysealis hemimelica in a young girl: role of MRI in the diagnosis and follow-up Antonio Acquaviva a, *, Giovanna Municchi a , Silvia Marconcini a , Fernando Mazzarella b , Rossella Occhini c , Paolo Toti c , Maria Antonietta Mazzei b , Luca Volterrani c a Department of Pediatrics, Obstetrics and Reproductive Medicine, University of Siena, Viale Bracci 16, 53100 Siena, Italy b Department of Radiology and Orthopedics, University of Siena, Siena, Italy c Department of Human Pathology and Oncology, University of Siena, Siena, Italy Received 31 October 2003; accepted 28 April 2004 Available online 23 July 2004 Abstract This report describes a sporadic case of dysplasia epiphysealis hemimelica that developed in the proximal tibia of a 21-month-old girl. Three years after the surgical intervention the patient has made complete clinical recovery with a normal range of motion, a walk with no limping or pain, no leg length discrepancy or angular knee deformity. Even though the proximal tibia does not represent an infrequently involved site, we report the clinical, pathological and radiological features of our case both for the extreme rarity of dysplasia epiphysealis hemimelica and the very young age of the patient. The authors underline also the role of magnetic resonance imaging in the diagnosis, management and follow-up of this very rare condition. © 2004 Elsevier SAS. All rights reserved. Keywords: Dysplasia epiphysealis hemimelica; Magnetic resonance imaging; Computed tomography; Plain radiography 1. Introduction Dysplasia epiphysealis hemimelica (DEH) is an extremely rare skeletal developmental disorder affecting the epiphysis in young children. First described by Mouchet and Belot [1] and sometimes called Trevor’s disease [2], it is characterized by asymmetric enlargement of one or more epiphysis of the joint, usually in the lower extremities due to cartilaginous overgrowth. Males are affected three times as frequently as girls [3]. We describe a girl who presented DEH at a very young age and fully recovered after surgical intervention, emphasizing the role of magnetic resonance imaging (MRI) in the diagnosis, management and follow-up of this extremely rare condition. 2. Case report The patient was the first child of healthy, non- consanguineous parents. The medical history of the family was unremarkable. Pregnancy was uneventful and delivery was at term with normal birth weight and length. At the age of 20 months, parents noticed lumping on her left lower limb; no history of trauma was elicited. On admission to our depart- ment physical examination revealed a hard-elastic and tender protuberance over the medial side of the proximal third of the left tibia. There was no significant erythema on the covering skin. Length and weight were within normal range. Mental development was normal. Clinical evaluation was otherwise unremarkable The left knee X-ray showed irregular calcified mass on the medial side of superior tibial physis, with swelling of soft parts. Cortical involvement of medial physis of the tibia was present, apparently with no abnormalities of epiphyseal nucleus (Fig. 1). On the basis of the radiography, DEH was suspected and the young patient underwent com- puted tomography (CT) examination to better evaluate the relationship between irregular calcification and proximal epiphyseal nucleus of the tibia. CT scan revealed an irregular ossified lesion arising from the medial portion of the proximal epiphyseal nucleus and cortical involvement of the medial side of the tibia (Fig. 2). A biopsy of lesion was performed. Histological examination showed proliferation of * Corresponding author. Tel.: +39-0577-586-547; fax: +39-0577-586-143. E-mail address: acquaviva@unisi.it (A. Acquaviva). Joint Bone Spine 72 (2005) 183–186 www.elsevier.com/locate/bonsoi © 2004 Elsevier SAS. All rights reserved. doi:10.1016/j.jbspin.2004.04.003