Osteosarcoma

Osteosarcoma
The commonest type of primary bone cancer is osteosarcoma. It is most often diagnosed in children and teenagers but can occur at any age. Osteosarcomas can grow anywhere in the skeleton. But the commonest sites are Lower thigh (femur)
Upper shin bone (tibia), Upper arm (humerus) and Lower shin bone.

read more at http://www.cancerhelp.org.uk/help/default.asp?page=4417