Common Sites for Osteosarcoma
The most frequent sites for osteosarcoma are the metaphyseal areas of the distal femur and proximal tibia, which together account for approximately 60% of all cases, representing the regions of maximum skeletal growth. 1, 2
Primary Anatomic Distribution
Long Bones of the Extremities (Most Common)
Distal femur (42% of cases): Approximately 75% of femoral osteosarcomas occur in the distal metaphyseal region, making this the single most common site overall 3, 4
Proximal tibia (19% of cases): About 80% of tibial osteosarcomas arise in the proximal metaphyseal region 3, 5
Proximal humerus (10% of cases): Approximately 90% of humeral osteosarcomas develop in the proximal metaphysis 3, 5
Key anatomic principle: These three sites around the knee and shoulder correspond to the physes of maximum growth during normal skeletal development, explaining why osteosarcoma peaks during the adolescent growth spurt 1
Less Common Sites
Skull or jaw (8% of cases): More common in older adults with secondary osteosarcoma 3, 6
Pelvis (8% of cases): Associated with worse prognosis due to difficulty achieving complete surgical resection 3, 6
Other long bones: Distal radius, distal ulna, and fibula are extremely rare locations 7
Variant-Specific Locations
Surface Variants
Parosteal osteosarcoma (5% of all osteosarcomas): The posterior aspect of the distal femur is the classic location for this low-grade surface variant 1
Periosteal osteosarcoma: Most commonly involves the femoral diaphysis, followed by the tibia 1
Intramedullary Variants
High-grade intramedullary (conventional) osteosarcoma (80% of cases): Predominantly affects the metaphyseal regions of distal femur and proximal tibia 1
Low-grade intramedullary osteosarcoma (<2% of cases): Shares the same anatomic predilection as conventional osteosarcoma despite different biology 1
Clinical Implications for Site Recognition
Around the knee accounts for approximately 60% of all osteosarcoma cases, making any painful bone lesion in this region in an adolescent or young adult highly suspicious for osteosarcoma until proven otherwise. 2
Age-Related Site Considerations
Adolescents and young adults (peak age 10-14 years): Metaphyseal regions of distal femur and proximal tibia predominate, correlating with pubertal growth spurt 1, 3
Adults over 65 years: Secondary osteosarcoma related to Paget disease can occur in any bone affected by Paget disease, including flat bones like pelvis and skull 1, 3