Which clinical and radiographic features suggest malignant degeneration of an osteochondroma

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.