Juxta-cortical chondrosarcomas, also known as periosteal chondrosarcomas, are indistinguishable histologically from conventional medullary chondrosarcomas and are therefore graded into low, intermediate or high-grade tumours (see chondrosarcoma grading).
Typically it occurs in adults in their 3rd and 4th decades and is slightly more frequent in males.
Unlike conventional chondrosarcomas, they arise from the surface of the bone, lifting the periosteum over themselves as a fibrous pseudocapsule. The underlying cortex is usually thickened or may be eroded, however, extension into the medullary cavity is not usual. Where the periosteum is lifted a Codman triangle may be seen. In addition to the usual chondroid matrix, metaplastic ossification is also common.
They typically arise from long bones, with a predilection for the posterior aspect of the distal femur.
- affects younger patients (typically 10-25 years of age)
- periosteal reaction perpendicular to the cortex
- diaphyseal rather than metaphyseal
- stalk of bony attachment
- otherwise similar appearance, location and demographics
- juxtacortical chondroma
- parosteal lipoma
- 1. Varma DG, Ayala AG, Carrasco CH et-al. Chondrosarcoma: MR imaging with pathologic correlation. Radiographics. 1992;12 (4): 687-704. doi:10.1148/radiographics.12.4.1636034 - Pubmed citation
- 2. Murphey MD, Walker EA, Wilson AJ et-al. From the archives of the AFIP: imaging of primary chondrosarcoma: radiologic-pathologic correlation. Radiographics. 2003;23 (5): 1245-78. doi:10.1148/rg.235035134 - Pubmed citation
- 3. Chaabane S, Bouaziz MC, Drissi C et-al. Periosteal chondrosarcoma. AJR Am J Roentgenol. 2009;192 (1): W1-6. doi:10.2214/AJR.08.1159 - 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
- 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
- simple bone cyst
- impending fracture risk