Age group affected by osteosarcoma -

Ans. is 'b' i.e., 10 - 20 years * Osteogenic sarcoma is the most common primary malignant tumor of bone in children.* This is predominantly a tumor of childhood or adolescence, occuring most commonly in the 10-25 years.* The most common site of involvement is metaphysis of long bone around knee: -# Lower end of femur (45%)# Upper end of Tibia (25%)* Other sites of involvement are proximal humerus (9%), and very rarely radius and fibula.* The usual presentation is local pain associated with gradually increasing swelling.* On examination there may be local tenderness and warmth overlying skin.* About 10% of patients have pulmonary metastasis by the time they first seen.