The World Health Organization defines osteosarcoma as a primary osseous malignant neoplasm composed of mesenchymal cells producing osteoid and immature bone, even if only in small amounts.

Epidemiology:

• Osteosarcoma is the most common non-haematological primary malignant neoplasm of bone in children and adolescents.
• Although it can occur at any age, it usually affects patients in the second and third decade of life with a peak incidence between 13 and 16 years of age.
• It is more common in males than females.

Risk factors:

• Adolescence - Most patients are under 25
• Paget’s disease
• Radiotherapy
• Rothmund Thomdon syndrome (rare autosomal recessive disease)
• Familial retinoblastoma syndrome
• Li-Fraumeni syndrome

PC

*presence of R/F

• Worsening persistent localised pain over weeks to months - Worse at night
• Mass/swelling
• Antalgic gait