These two terms are very general terms. A bone tumor refers to any abnormal growth from the bone or in the bone, benign or malignant. Bone cancer refers to a malignant bone tumor. It can be a primary malignant tumor like an osteosarcoma, Ewing's sarcoma or chondrosarcoma. It can also be a metastatic carcinoma such as a breast cancer, lung cancer, prostate cancer, kidney cancer and thyroid cancer. It is important to differentiate between the various types of cancers that affect the bone because each has its own type of treatment and prognosis.