Which clinical and radiographic features suggest malignant degeneration of an osteochondroma?
Features suggesting malignant degeneration include pain, growth after closure of the growth plate, bony destruction, a thickened cartilage cap, and a soft tissue mass.
The risk of malignant transformation of a solitary osteochondroma is approximately 1%, whereas the risk with multiple hereditary exostoses is much higher, to 25% to 30%.
A sessile lesion is more likely to degenerate, usually undergoing malignant transformation to a chondrosarcoma.
