A 23 year old male presented with pain and localized tenderness of the left lower limb of 5 months duration. A radiograph of the lower leg was asked for. Ewing's sarcoma belongs to a group of highly malignant tumours involving bone, characterised histologically by numerous small round cells. Within this group are included metastatic neuroblastoma, non-Hodgkins' lymphoma and undifferentiated tumours. The majority of patients are between 5 and 30 years of age.
Metastatic spread occurs early to other bones and lungs.
The lesion is essentially destructive, ill-defined and principally involves the medullary cavity. Cortical erosions and periosteal reactions occur early, and a periosteal reaction may perhaps be the only early sign of abnormality. Although the onion-peel lamellar type of periosteal reaction has been described for this lesion, it is seen infrequently and may also be noted in other lesions such as osteosarcoma and infection. Codman's triangles are observed in Ewing's sarcoma, they represent elevation of periosteal new bone at the margins of cortical erosions.