Distinguishing between enchondromas and low-grade conventional chondrosarcomas is a frequent difficulty as the lesions are both histologically and radiographically very similar.
It is important to remember, though, that differentiating between them may be a moot point since both can either be closely followed up clinically and radiologically or treated if symptomatic.
Radiographic features
Useful features include:
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size
lesion size over 5-6 cm favors chondrosarcoma
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cortical breach
seen in 88% of long-bone chondrosarcomas
seen in only 8% of enchondromas
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deep endosteal scalloping involving > 2/3 of cortical thickness
seen in 90% of chondrosarcomas
seen in only 10% of enchondromas
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permeative or moth-eaten bone appearance
seen in high-grade chondrosarcomas, not in low-grade tumors
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soft tissue mass beyond bone
not seen in enchondroma
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increased uptake on bone scan
seen in 82% of chondrosarcomas
seen in only 21% of enchondromas
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location
hands and feet are uncommon locations for chondrosarcoma
outside hand and feet, chondrosarcomas outnumber enchondromas 5:1
spine, pelvis, sacrum, and ribs are rare locations for enchondromas
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patient age
enchondromas commonly appear in young adults
chondrosarcomas tend to appear in middle-aged patients
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pain
chondrosarcomas almost always present with pain
enchondromas are painless unless they cause a pathological fracture
