Clear cell chondrosarcomas are a subtype of chondrosarcoma constituting 1-2% of all chondrosarcomas. They are typically low-grade (see chondrosarcoma grading) and get their name from the presence of clear cell chondrocytes which contain abundant vacuolated cytoplasm due to the presence of glycogen.
They typically present in patients in their 3rd to 5th decade, with men being affected twice as often as women (M:F ~ 2:1 ).
Symptoms persist for an average duration of one year, suggesting slow growth of the lesion.
In approximately half of the cases, conventional chondrosarcomatous elements are also present. Macroscopically, haemorrhage and cyst formation are common, and radiographically matrix calcification is uncommon.
The lesion is most often in an epiphyseal location (in contradistinction to conventional chondrosarcoma, which is usually metaphyseal-diaphyseal).
- tubular long bones: 85-90%
- proximal femur: 55-60% (commonest)
- proximal humerus: 10-15%
- distal femur or proximal tibia: 10-15%
On radiographs, clear cell chondrosarcomas are predominantly lytic and expansile.
- endosteal irregularity is not infrequent
- periosteal reaction does not occur
- soft tissue extension and cortical break are usually seen only if a pathologic fracture occurs
- low reported incidence of calcified matrix
- in up to 20% of cases, a peripheral rind of sclerosis is apparent (simulating a benign lesion)
Typically reported signal characteristics on MR imaging include:
- T1: homogeneous intermediate signal intensity
- T1 C+ (Gd): may show heterogeneous enhancement
- T2: heterogeneous high signal intensity
Treatment and prognosis
A clear cell chondrosarcoma is a relatively slow-growing, low-grade malignant tumour. It carries a much better prognosis than a conventional chondrosarcoma. Because of the relatively benign appearance of the lesion on radiographs, surgical intervention is often delayed. Distant metastases have, however, been reported in the lung, brain, and bones.
- 1. Murphey MD, Walker EA, Wilson AJ et-al. From the archives of the AFIP: imaging of primary chondrosarcoma: radiologic-pathologic correlation. Radiographics. 23 (5): 1245-78. doi:10.1148/rg.235035134 - Pubmed citation
- 2. Varma DG, Ayala AG, Carrasco CH et-al. Chondrosarcoma: MR imaging with pathologic correlation. Radiographics. 1992;12 (4): 687-704. Radiographics (abstract) - Pubmed citation
The differential diagnosis for bone tumours is dependent on the age of the patient, with a very different set of differentials for the paediatric patient.
- bone-forming tumours
- cartilage-forming tumours
- chondromyxoid fibroma
- juxtacortical chondroma
- fibrous bone lesions
- bone marrow tumours
- other bone tumours or tumour-like lesions
- aneurysmal bone cyst
- benign fibrous histiocytoma
- giant cell tumour of bone
- Gorham massive osteolysis
- haemophilic pseudotumour
- intradiploic epidermoid cyst
- intraosseous lipoma
- musculoskeletal angiosarcoma
- musculoskeletal haemangiopericytoma
- primary intraosseous haemangioma
- post-traumatic cystic bone lesion
- simple bone cyst
- impending fracture risk