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Osteosarcoma — RACP Paediatrics MCQ

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ModerateHaematology & OncologyOsteosarcomaRACP Paediatrics

A 14-year-old boy presents with a 2-month history of a painful, enlarging mass at the distal femur. X-ray shows a sunburst periosteal reaction, Codman triangle, and soft tissue extension. Alkaline phosphatase is elevated. What is the most likely diagnosis?

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Correct answer: E — Osteosarcoma

Osteosarcoma is the most common primary bone malignancy in adolescents. The distal femur is the most common site. X-ray findings include sunburst periosteal reaction, Codman triangle (periosteal elevation), osteolytic and osteoblastic changes, and soft tissue extension. Elevated ALP is common. Staging includes MRI of the primary tumour and CT chest (for lung metastases).

Reference: ANZCHOG – 2024 – Treatment Guidelines: Osteosarcoma