Osteosarcoma
Typical pattern:
- adolescent or young adult
- metaphysis of a long bone, especially around the knee
- pain and swelling
- aggressive mixed lytic/sclerotic lesion with osteoid production
Diagnosis requires biopsy after imaging/staging.
Treatment is multidisciplinary:
- systemic chemotherapy
- wide surgical resection when feasible
- reconstruction according to site and patient
Histological response to preoperative chemotherapy is prognostically important.
Osteosarcoma is a malignant mesenchymal tumour that produces osteoid.
Typical features:
- adolescents/young adults for conventional high-grade disease
- metaphyseal long-bone predilection
- aggressive mixed lytic/sclerotic appearance
- osteoid matrix
- cortical destruction and soft-tissue mass
Treatment generally combines systemic chemotherapy with wide surgical resection where feasible.
Important prognostic issues include metastatic disease and response to chemotherapy.
Ewing sarcoma
Typical pattern:
- child, adolescent or young adult
- diaphyseal or pelvic lesion
- permeative destruction with soft-tissue mass
- systemic symptoms can mimic infection
Molecular abnormalities involving EWSR1, commonly an EWS-FLI1 fusion, support diagnosis in appropriate pathology.
Treatment combines:
- multi-agent chemotherapy
- local control with surgery and/or radiotherapy
Ewing sarcoma commonly affects children and young adults.
Features can include:
- diaphyseal or metaphyseal lesion
- permeative destruction
- large soft-tissue mass
- systemic inflammatory features
- layered periosteal reaction
Treatment is multimodal, usually incorporating chemotherapy with local control by surgery and/or radiotherapy.
Because Ewing can resemble infection, biopsy and microbiological consideration may both be important.
Chondrosarcoma
More common in adults. Management depends on subtype and grade.
Conventional chondrosarcoma is relatively resistant to standard chemotherapy and radiotherapy, making adequate surgical excision central to treatment.
Conventional chondrosarcoma usually affects older adults compared with osteosarcoma/Ewing.
Features include:
- pain
- chondroid matrix
- endosteal scalloping
- cortical destruction or soft-tissue extension in more aggressive lesions
Conventional chondrosarcoma is relatively resistant to standard chemotherapy and radiotherapy, making complete surgical excision particularly important.
Surgical margins
Conceptually describe surgery as:
- intralesional
- marginal
- wide
- radical
Modern sarcoma surgery aims for oncologically adequate margins while preserving useful function whenever possible.
Limb salvage
Limb salvage is possible for most extremity sarcomas when an adequate oncological resection can be achieved with a functional reconstruction. Major neurovascular encasement, uncontrolled contamination or a non-functional predicted limb may make amputation more appropriate.
Limb salvage is possible when a wide margin can be achieved while preserving a functional limb.
Reconstruction options include:
- endoprosthesis
- allograft or biological reconstruction
- rotationplasty in selected children
- arthrodesis in selected sites
Wide excision
Oncological surgery is planned around compartments and margins.
A wide margin removes the tumour with a cuff of uninvolved tissue. The reconstruction is planned only after the oncological resection is defined.
Pathological fracture
A pathological fracture through a primary sarcoma complicates treatment but is not automatically an indication for amputation. Management should remain within a specialist sarcoma pathway; unplanned internal fixation risks major contamination.
FRCS synthesis
For malignant bone tumours, focus on tumour biology + staging + biopsy + wide local control + appropriate systemic therapy, with reconstruction secondary to achieving oncological clearance.