Enchondroma protuberans. Report of a case and its distinction from chondrosarcoma and osteochondroma adjacent to an enchondroma.

Enchondroma protuberans has been defined as an exophytic enchondroma of a long bone. We contrast a case of enchondroma protuberans with two cases of coincident enchondroma and osteochondroma. Our cases and the previously published ones lead us to believe that enchondroma protuberans is probably an enchondroma variant and that its unusual growth pattern may be related to the oblique orientation of the proximal humeral epiphysis. Unlike osteochondroma, which may be treated surgically by removing the cartilage cap and, in some cases, the stalk, enchondroma protuberans requires intralesional curettage. Enchondroma protuberans must be distinguished radiographically from chondrosarcoma.