Plain film of an osteochondroma involving the distal one-third of the femur in a 50 y/o male. The cortex and the medullary cavity of the lesion are continuous with that of the underlying bone. The adjacent cortex has flared up to form the base of the tumor. The margins are irregular without a soft tissue component or a fracture. Case produced with permission, courtesy of Dr. Frank Gaillard. Radiopaedia. Complete case is here.