Age
Age distribution is similar to conventional osteosarcoma
Gender
M:F = 2:1
Location
Most commonly located in proximal metaphyseal and diaphyseal regions of proximal one third of femur or proximal tibia or distal femur
Radiological Appearance
Juxtacortical soft tissue mass with internal spiculated areas of bone extending perpendicular to cortex
Tumor effect on bone
- Cortex may have a "scooped out" appearance
- May be areas of stippled calcification characteristic of cartilage-producing tumors
- Tumor radiographically dense at base, adjacent to cortex with peripheral immature ossification extending into soft tissue mass
Bone response to tumor
- May be evidence of cortical thickening; cortical destruction may occur
- Abundant periosteal reaction with Codman’s triangles common
Differential diagnosis
- High-grade surface osteosarcoma
- Parosteal chondrosarcoma
- Myositis ossifications
Treatment
- Requires wide excision
- Generally a low-grade malignant lesion, but depending on grade of cytological changes, chemotherapy may be recommended for high-grade lesions