Age / Sex : 10 / M

Dysplasia epiphysealis hemimelica (Trevor’s disease)

Discussion

Findings:  

Radiograph) Focal irregular bony protrusion with irregular margin in the lateral side of talus. Other separate irregular ossifications at the posterolateral aspect of the aforementioned lesion.

MRI) Bony protrusion extending from talus with overlying cartilage cap. Enlarged lateral aspect of talus and deformity of adjacent calcaneus.

Differential Diagnosis: Synovial osteochondromatosis

Diagnosis: Dysplasia epiphysealis hemimelica

Discussion: Dysplasia Epiphysealis Hemimelica (Trevor’s disease) is a rare developmental disorder arising from an epiphysis. This disease predominantly affects lower extremity, medial side of the limb (hemimelic), and boys. It is categorized into three different forms: a localized form (monostotic involvement), a classic form (more than one area of osseous involvement in a single extremity), and a generalized or severe form (disease involving an entire single extrem- ity). Histologic findings are almost identical to those of an osteochondroma, consisting of normal bone and hyaline cartilage with abundant enchondral ossification. In radiography, premature ossification centers appear with abnormal morphology (enlargement, lobulation, asymmetry). Stippled calcification can be seen commonly. As child grows older, irregular ossficiation becomes confluent and merges with adjacent epiphysis. Premature closure of physis can result deformity or length discrepancy. CT can confirm the continuity of the mass with the epiphysis. MR image can show the similar signal intensity of the lesion and involved epiphyseal cartilage.

References:

1.Murphey MD, Choi JJ, Kransdorf MJ, Flemming DJ, Gannon FH. Imaging of osteochondroma: variants and complications with radiologic-pathologic correlation. Radiographics. 2000 Sep-Oct;20(5):1407-34.

2.Glick R, Khaldi L, Ptaszynski K, Steiner GC. Dysplasia epiphysealis hemimelica (Trevor disease): a rare developmental disorder of bone mimicking osteochondroma of long bones. Human Pathology. 2007 Aug;38(8):1265-72.