Malignant bone tumours are cancers, and can be spread to other parts of the body. Malignant tumours may be primary or secondary.
For example, a primary malignant bone tumour, also known as a bone sarcoma, is a tumour that arises directly from that bone. On the other hand, a secondary bone tumour is a tumour that has spread from another part of the body to that bone. This is also known as metastatic bone cancer, and most of them have spread from other primary tumours such as prostate cancer, breast cancer, lung cancer, kidney cancer, thyroid cancer or melanoma.