الفهرس 
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Abstract
Osteosarcoma, is the most common primary bone malignancytypically during the adolescent growth spurt but there is a second, smallerpeak in the elderly (Mirabello L., et al., 2009). Osteosarcoma represents approximately 55%of child andadolescent malignant bone tumors (Mirabello L., et al.,2009). It is rarelydiagnosed before the age of five, but the incidence increases with ageuntil around puberty. This primary peak is followed by a decrease andplateau in incidence in individuals between 25 and 60 years of ageSharon A. Savage, et al., 2011)This is also noted in childhood and adolescent osteosarcoma rates are relatively consistent around the world, ranging between 3 to 4.5cases/million population/year (Stiller C. A. et al., 1997).The rates in older persons have been less studied; current estimates are 1 to 2 cases/million population/year for persons aged 25 to 59 years and 1.5 to 4.5 cases/million population/year for persons over the age of 60 (Mirabello L., et al., 2009).There are a limited number of proven risk factors associated with osteosarcoma. It occurs more frequently after therapeutic radiation for a different cancer, in individuals with certain cancer predisposition syndromes, and in those with Paget disease of the bone. However, the majority of osteosarcoma cases occur in the absence of these risk factors. Numerous studies of growth and other genetic risk factors have been conducted but strong data on risk for apparently sporadic osteosarcoma are limited. (Sharon A. Savage, et al., 2011).Introduction3Elderly individuals have a higher incidence of osteosarcoma related to Paget disease of the bone or as a consequence of treatment for a different cancer (C. A. Stiller.et al., 1997). Osteosarcoma incidence has somewhat increased over time in younger cases and decreased in elderly individuals (Mirabello L., et al., 2009).In Egypt, bone cancers had incidence rate of 1.62% for males.