Fact-sheet: Osteochondroma - Exostosis
Updated on 09/17/2021 at 12:16 PM
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Definition
Most common benign cartilage-containing bone tumor, characterized by hyperplastic bone growth that ceases at epiphyseal fusion
Radiography
Expansile lesion with cortical and medullary continuity with the host bone,
sometimes covered by cartilage which may appear as arc-like calcifications
CT
Cortical and medullary continuity, pathognomonic.
Covered in 75% of cases by hypodense cartilage 6-8 mm thick once growth is complete, but up to 30 mm during growth
MRI
Cortical and medullary continuity.
Hyaline cartilage markedly hyperintense on T2, and iso- to hypointense on T1.
Mild peripheral enhancement after gadolinium administration
Differential diagnosis
Malignant transformation into osteosarcoma/chondrosarcoma: any cartilaginous cap exceeding 15 mm after completion of growth should be considered suspicious