Bone cancer, also known as primary bone cancer, develops in the cells of bone or cartilage. It is a cancerous (malignant) tumour formed by a group of cancerous cells that can invade and destroy neighbouring bone tissue.

 Often derived from osteoblasts or osteoclasts, they disrupt the delicate balance of bone remodelling, inducing pathological changes. The main varieties include osteogenic sarcoma and multiple myeloma, each with distinct patterns of development and progression. Genetic alterations, such as mutations in tumour suppressor genes, are often key instigators of these bone cancers. This type of cancer is very rare in adults over the age of 40, but is more common in children, adolescents and young adults.

There are different types of bone tumours, including osteosarcoma, Ewing's sarcoma, chondrosarcoma, fibrosarcoma, angiosarcoma and high-grade undifferentiated polymorphous sarcoma.  It is important to note that bone cancer is different from bone metastases, which are secondary tumours arising from cancers of other organs that spread to the bone.