Bone and soft-tissue sarcomas — branching viva

Opening question

A thirteen-year-old boy has three months of deep night pain in the distal thigh and a firm mass above the knee, and his radiograph shows a mixed lytic and sclerotic distal femoral metaphyseal lesion with sunburst spicules and a Codman triangle. Name the diagnosis, justify the radiographic features, and give the staging panel and the biopsy principle. [1]

Branch 1 — the chemotherapy backbone and the histologic response

The histology confirms a high-grade osteosarcoma. Name the chemotherapy backbone, explain why it is given both before and after the surgery, and state how the histologic response guides the postoperative treatment. What role does radiotherapy have, and why? [1]

Branch 2 — reframing the lesion as Ewing sarcoma

The same boy instead presents with a permeative diaphyseal lesion in the femoral shaft, a large soft-tissue mass, fever and malaise, initially treated as osteomyelitis. What is the new diagnosis, what does the radiograph show, what is the defining molecular marker, and how does the treatment backbone differ from the osteosarcoma? [2]

Branch 3 — the head-and-neck mass and the rhabdomyosarcoma

A four-year-old girl presents with a painless orbital mass and proptosis, and the biopsy shows a rhabdomyosarcoma. How does the subtype and the fusion drive the risk group and the prognosis, what is the chemotherapy backbone, and how does the role of radiotherapy differ from the osteosarcoma? [3][4]

Closing — coordination and survivorship

In one sentence, what is the principle of managing the paediatric sarcoma across the lifespan, and why does the general paediatrician sit at the centre of the recognition, the safe referral and the survivorship surveillance? [1][3]