Chondrosarcoma
- Lesion
A malignant cartilage tumour of adults, mostly in the pelvis, shoulder and ribs. Its grade decides how it behaves.
What it is
Chondrosarcoma is the second commonest matrix-producing malignant tumour of bone after osteosarcoma and affects mainly people over forty. Most are conventional chondrosarcomas, arising either inside the medullary cavity (central, often with IDH1 or IDH2 mutations) or on the surface of a pre-existing osteochondroma (peripheral, with EXT loss). They favour the axial skeleton: pelvis, shoulder girdle, ribs and proximal femur. Prognosis depends on grade; variants include dedifferentiated, clear cell and mesenchymal chondrosarcoma.
Structure
- Gross: large, lobulated, glistening grey-blue mass with gritty calcifications, eroding cortex and growing into soft tissue.
- Micro: hyaline or myxoid cartilage permeating the marrow and entrapping host trabeculae (unlike enchondroma).
- Increasing grade: more cells, binucleated and atypical chondrocytes, mitoses and myxoid change.
- Dedifferentiated: abrupt junction between low-grade cartilage and a non-cartilaginous high-grade sarcoma.
Step by step
- Central tumours arise from mutant medullary chondrocytes (IDH1/IDH2), sometimes from a pre-existing enchondroma.
- Peripheral tumours arise in the cap of an osteochondroma after further mutations.
- Malignant chondrocytes grow in lobules, permeate marrow and scallop then breach the cortex.
- Higher-grade tumours acquire CDKN2A loss and other changes and spread by the blood to the lungs.
- A subset dedifferentiates into a high-grade, non-cartilaginous sarcoma.
Markers
- IDH1/IDH2 mutation
- S100 in chondrocytes
- HEY1-NCOA2 (mesenchymal type)
Clinical notes
- Slowly growing painful mass in the pelvis or shoulder of an older adult.
- X-ray: lytic lesion with ring-and-arc calcification, deep cortical scalloping and cortical thickening.
- Pain from a cartilage lesion in a large bone favours chondrosarcoma over enchondroma.
Test yourself
Think of the answer, then tap the question to see it.
Which age group gets chondrosarcoma?
Adults, mostly over 40.
Which mutations are frequent in central chondrosarcoma?
IDH1 or IDH2.
What is dedifferentiated chondrosarcoma?
A low-grade chondrosarcoma with an abrupt high-grade non-cartilaginous sarcoma component; it has a poor prognosis.
Which histologic feature separates chondrosarcoma from enchondroma?
Permeation of the marrow with entrapment of host trabeculae.
Elsewhere in DurgiPedia
Connections
Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Primary Bone Cancer - NCI (National Cancer Institute, 2025); Ollier disease: MedlinePlus Genetics (MedlinePlus, US National Library of Medicine, 2025).
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Representative model, for educational purposes only.