Dysplasia epiphysealis hemimelica
Dysplasia epiphysealis hemimelica (DEH), also known as Trevor disease, is an extremely rare, non-hereditary disease that is characterised by osteochondromas arising from the epiphyses.
The incidence is estimated at ~1:1,000,000 3. There is a recognised male predilection (M:F = 3:1). It usually presents in young children.
Azouz et al. has proposed the following classification:
- classic form: characteristic hemimelic distribution involving more than one bone or epiphysis within a single lower extremity
- localised form: single bone affection unilateral or bilateral
- generalised form: involving the whole limb from pelvis to foot
The aetiology is uncertain but is thought to be congenital.
- lower extremity is more common than upper extremity
- distal ends are more affected
- medial aspects are affected twice as commonly as lateral
- the distal femur is one of the most frequent sites
- other sites are around the ankle joint
Typically shows an irregular mass with focal ossification arising from one side of the affected epiphysis 3. This can result in widening of the affected joint.
Useful for assessing cortical continuity with the epiphysis.
MRI is useful for evaluation of underlying ligaments and cartilages. Osteochondral overgrowth signal intensity will be similar to normal epiphyseal cartilage and bone.
Treatment and prognosis
Surgical excision of mass with preservation of joint.
- fragmentation and detachment leading to intra-articular bony fragments
- deformation of the ligaments and tendons affecting the joint mechanism
- chronic tendonitis and tenosynovitis due to chronic irritation of tendons by mass or bony fragments
- development of secondary osteoarthritis of affected joint
The differential diagnosis for bone tumours is dependent on the age of the patient, with a very different set of differentials for the paediatric patient.
- bone-forming tumours
- cartilage-forming tumours
- chondromyxoid fibroma
- fibrous bone lesions
- bone marrow tumours
- other bone tumours or tumour-like lesions
- aneurysmal bone cyst
- benign fibrous histiocytoma
- giant cell tumour of bone
- Gorham massive osteolysis
- haemophilic pseudotumour
- intradiploic epidermoid cyst
- intraosseous lipoma
- musculoskeletal angiosarcoma
- musculoskeletal haemangiopericytoma
- primary intraosseous haemangioma
- simple bone cyst
- impending fracture risk
- 1. Peduto AJ, Frawley KJ, Bellemore MC et-al. MR imaging of dysplasia epiphysealis hemimelica: bony and soft-tissue abnormalities. AJR Am J Roentgenol. 1999;172 (3): 819-23. AJR Am J Roentgenol (abstract) - Pubmed citation
- 2. Haddad F, Chemali R, Maalouf G. Dysplasia epiphysealis hemimelica with involvement of the hip and spine in a young girl. J Bone Joint Surg Br. 2008;90 (7): 952-6. doi:10.1302/0301-620X.90B7.20784 - Pubmed citation
- 3. Araujo CR, Montandon S, Montandon C et-al. Best cases from the AFIP: dysplasia epiphysealis hemimelica of the patella. Radiographics. 26 (2): 581-6. doi:10.1148/rg.262055126 - Pubmed citation
- 4. Rosero VM, Kiss S, Terebessy T et-al. Dysplasia epiphysealis hemimelica (Trevor's disease): 7 of our own cases and a review of the literature. Acta Orthop. 2007;78 (6): 856-61. doi:10.1080/17453670710014662 - Pubmed citation
- 5. Arealis G, Nikolaou VS, Lacon A et-al. Trevor's Disease: A Literature Review regarding Classification, Treatment, and Prognosis apropos of a Case. Case Rep Orthop. 2014;2014: 940360. doi:10.1155/2014/940360 - Free text at pubmed - Pubmed citation