Chondrosarcoma

Chondrosarcoma is a malignant tumour in which neoplastic cells produce cartilage matrix.

It predominantly affects adults.

Common sites include:

• Pelvis
• Proximal femur
• Proximal humerus
• Ribs
• Scapula

The major biological distinction is between lower grade conventional cartilage tumours and aggressive high grade or specialised chondrosarcoma subtypes.

Histological grade

Grade 1

Low grade tumour with relatively low metastatic potential.

In appendicular sites, some lesions previously termed grade 1 chondrosarcoma are classified as atypical cartilaginous tumour because their metastatic risk is very low.

Grade 2

Intermediate grade, with greater local aggressiveness and metastatic potential.

Grade 3

High grade tumour with substantial metastatic risk.

Important specialised subtypes include:

• Dedifferentiated chondrosarcoma
• Mesenchymal chondrosarcoma
• Clear cell chondrosarcoma

These behave differently from conventional low grade disease.

Pain is the most important symptom.

A cartilage lesion that has been radiographically stable but develops:

• Progressive pain
• Night pain
• Increasing size
• Cortical destruction
• Soft tissue extension

requires investigation for malignant transformation.

Large pelvic tumours can present late with:

• Deep pelvic pain
• Mass
• Neurological symptoms
• Urinary or bowel compression

• Plain radiographs: often show a destructive lesion with chondroid matrix mineralisation.

• MRI: define medullary extent, soft tissue extension and relation to major neurovascular structures.

• CT: particularly useful for matrix calcification and cortical destruction.

• CT chest: stage intermediate and high grade disease for pulmonary metastases.

• Biopsy should occur only after imaging and multidisciplinary planning.

Sampling error is important because large cartilage tumours can contain areas of differing histological grade. Target the most aggressive appearing component.

Surgery

Surgery is the principal curative treatment for most chondrosarcomas. Conventional chondrosarcoma responds poorly to standard chemotherapy and radiotherapy.

Atypical cartilaginous tumour of an extremity

A small asymptomatic lesion without aggressive radiological features can sometimes be observed.

A symptomatic or progressive lesion can undergo:

Extended intralesional curettage

with:

• High speed burr
• Local adjunct according to practice
• Bone graft or cement reconstruction

This preserves the adjacent joint and generally provides good control for appropriately selected appendicular low grade lesions.

Higher grade conventional chondrosarcoma

Grade 2 and 3 tumours require wide en bloc resection with negative margins.

Do not perform curettage of a high grade lesion.

The operation may require:

• Endoprosthetic reconstruction
• Pelvic resection
• Chest wall reconstruction
• Biological reconstruction

Margins have major prognostic importance.

Pelvic and axial chondrosarcoma

Even apparently low grade pelvic cartilage tumours behave more aggressively and are much harder to salvage after recurrence.

Pelvic and axial chondrosarcomas generally require wide surgical excision rather than intralesional treatment.

Dedifferentiated chondrosarcoma

This consists of conventional cartilage tumour adjacent to a high grade noncartilaginous sarcoma.

It has:

• High metastatic risk
• Poor prognosis
• High local recurrence risk

Treatment requires wide resection.

Systemic chemotherapy can be considered, often using osteosarcoma type agents in younger and fit patients, but treatment responsiveness is substantially less predictable than conventional osteosarcoma.

Mesenchymal chondrosarcoma

This rare subtype is more chemotherapy sensitive than conventional chondrosarcoma.

Treatment commonly combines:

• Wide resection
• Multiagent systemic chemotherapy
• Radiotherapy in selected cases

Systemic treatment frequently resembles Ewing sarcoma treatment.

Clear cell chondrosarcoma

Usually lower grade but locally recurrent if inadequately excised.

Treat with wide resection.

Radiotherapy

Conventional chondrosarcoma is relatively radioresistant.

Radiotherapy has a role for:

• Unresectable disease
• Inadequate margins when reoperation is impossible
• Skull base and spinal disease where complete resection is unsafe
• Palliation

High precision proton or carbon ion techniques can be valuable in selected axial tumours.

Metastatic disease

Pulmonary metastasectomy can be considered when:

• Disease is limited
• Primary tumour is controlled
• Complete pulmonary resection is achievable

Systemic treatment depends heavily on subtype and molecular findings rather than using one generic chondrosarcoma regimen.