Osteosarcoma femur LSBU

Description: Radiology case 444-3221 5 year old boy with with swelling of the right thigh.
The density of the diaphysis is expanded to an oval by dense thickening of the bone with a centre of radius in mid-diaphysis. There is an additional adjacent soft tissue mass, which has displaced normal muscles. The centre of mass tends a little to the proximal metaphysis and does not correspond with normal musculature. Although the soft tissue mass does not extend to the distal metaphysis, there is a lamellar perisosteal reaction that has thickened the bone over the medial side of the metaphysis. Proximally the bone margins are less well-defined, where strands of newbone extend into the enveloping soft tissue mass over the proximal metaphysis, particularly on its lateral side.