الفهرس 
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Abstract
Ewing’s sarcoma is one of the pediatric small round blue cell tumors that constitute 12% of cases of bone cancers. It is considered the second most frequent primary malignant bone tumor after osteosarcoma and it is slightly more common in boys (55: 45 male: female ratio) .[84,85]
In 1921, James Ewing described a malignant primary tumor of bone characterized by islands of anaplastic, small round cells closely associated with blood vessels formation that he termed (diffuse endothelioma of bone or endotheliomyeloma of bone)
Ewing’s sarcoma generally arises in the medullary canal of the shaft (hence its traditional inclusion among the marrow tumors), from which it permeates the cortex and invades the soft tissues and rarely it is predominantly periosteal lesion .[86,87,88]
The most frequent translocations found in Ewing tumors are reciprocal translocation (11; 22), (q24; q12) and t(21; 22), (q22; ql2) .Ewings sarcoma is found most frequently in the diaphysis of long bones and flat bones. The femur is the most common location followed by the tibia, humerus