What are the key clinical features that differentiate osteosarcoma, Ewing sarcoma, and chondrosarcoma in a young patient presenting with bone pain?

Osteosarcoma typically presents in adolescents and young adults with localized bone pain and swelling, often around the metaphysis of long bones such as the distal femur or proximal tibia. It may cause a palpable mass and is associated with aggressive bone destruction and periosteal reaction on imaging.

Ewing sarcoma usually affects children and young adults and presents with bone pain, swelling, and systemic symptoms such as fever and malaise. It commonly involves the diaphysis of long bones or the pelvis and may show an onion-skin periosteal reaction on X-ray. Systemic symptoms help differentiate it from osteosarcoma.

Chondrosarcoma is rarer in young patients and more common in adults; it presents with slowly progressive bone pain and swelling, often in the pelvis, femur, or shoulder girdle. It is characterized by cartilage matrix production and may show calcifications on imaging. It tends to have a more indolent course compared to osteosarcoma and Ewing sarcoma.

In summary, key differentiating clinical features in a young patient with bone pain include the age and site of the lesion, presence of systemic symptoms (fever in Ewing sarcoma), rate of symptom progression, and imaging characteristics such as periosteal reaction and matrix calcification. All require urgent referral for specialist assessment and imaging, including X-ray, as per UK guidelines for suspected bone sarcoma in children and young people ¹.