7 year old child presents with a lesion in upper tibia. X-ray shows radiolucent area with Codman's triangle and Sunray appearance. Diagnosis is :

Ans. is 'b' i.e. Osteosarcoma Codman's triangle and sunray appearance is seen in both Osteosarcoma & Ewing's tumor, but the catch point is location of the tumor i.e. upper end of tibia.Osteosarcoma - most commonly involves long bone metaphyses, especially around the knee and at the proximal end of the humerus.Ewing's sarcoma - most commonly involves the mid-diaphyseal region (common bones are tibia, fibula clavicle etc.) [About age Apley's writes - "Osteosarcoma is said to occur predominantly in children and adolescents".For differential diagnosis of bone tumors see Q.no. 153 of Nov. 2001