Case 3:

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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.
What is the diagnosis ?

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Imaging Findings :

Findings reveal a destructive lesion involving the lower diaphyseal shaft of the fibula with cortical erosions and soft tissue swelling.

Diagnosis :

Ewing's sarcoma

Discussion :

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.
Clinical findings include pain of several weeks' or months' duration and accompanied by local tender swelling, fever, anaemia and a raised ESR. The majority of patients are between 5 and 30 years of age.
The lesion is most often found in a long bone, the diaphysis being more commonly affected; in about 40% of cases, the axial skeleton is involved, particularly the pelvis and ribs. Metastatic spread occurs early to other bones and lungs.

Imaging Findings :

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. The tumour is highly vascular and shows soft tissue extension, these features are easily picked up on CT/MRI.

Contribution : Dr. Alpana Joshi, Dr. Rajesh Mayekar, Mumbai, India