BONE LESION

malignant growth of the bone caused by metastatic spread from cancer in other organs. Primary bone cancer is fairly uncommon, but bone lesions from metastases are seen in more than half of all cancer patients at the time of death. There are two types of metastatic bone lesion: osteoblastic, in which new bone is laid down in a disorganized fashion, and osteolytic, in which bone is destroyed, causing fractures and deep bone pain. Lung, breast, kidney, and prostate cancers are the primary tumours that most commonly cause bone lesions; lung cancer causes a typical punched-out lytic lesion while breast and prostate tumours more often produce osteoblastic metastases. Bone lesions commonly occur in the vertebral column, ribs, and pelvis, as well as in the long bones of the arms and legs. See also sarcoma.