Cartilage Tumours

Primary Chondrosarcoma

Chondrosarcomas are the third most common primary bone tumours (after myeloma and osteosarcoma).

Pathology

Primary Chondrosarcomas make up about 25% of primary osseous bone tumours. There are three grades:

  • Grade 1 (no mitoses, small chondroblasts, abundant cartilage matrix) - 10 year survival 90%, distant metastases 1%
  • Grade 2 (some mitoses, larger cells, cartilage matrix present)
  • Grade 3 (high mitoses, anaplastic cells, minimal cartilage matrix) - 10 year survival 25-50%

They arise within the medullary cavity of the ileum, proximal femur and proximal humerus in most cases. They can arise in the base of skull where they form an important differential diagnosis for chordoma.

Diagnosis

Imaging appearances are classical and include an expansile, medullary lesion with thickening of the cortex.

Treatment

Subtotal resection may be indicated for grade 1 lesions in areas where gross total resection would lead to functional problems. Intermediate and high grade tumours should have a maximal resection. Radiotherapy is indicated for subtotally resected grade 2-3 tumours. Doses should be 66 Gy in 33 fractions with wide margins.


Other Chondrosarcomas

Other types of chondrosarcoma include

  • Dedifferentiated chondrosarcoma: Contain primary chondrosarcoma with an area of dedifferentiated non-cartilagenous sarcoma. These often follow an aggressive course
  • Mesenchymal chondrosarcoma: Primary chondrosarcoma mixed with a small round cell tumour. These tumours may be locally recurrent or develop distant metastases even after many years.

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