Bone tissue contains two major classifications of cells: cells that deposit new bone tissue, and cells that reabsorb and break down old bone tissue. Throughout life, the bones undergo constant cellular remodeling to help maintain the integrity of the bone tissue. Bone lesions develop when the balance between bone breakdown and growth becomes disrupted, leading to the formation of abnormal growths. These growths can often be detected through medical testing, and are classified according to the invasiveness and severity of the lesion.
Non-neoplastic
Non-neoplastic bone lesions are those that are not caused by tumor growth. A non-neoplastic bone lesion may present as a bone cyst--a non-cancerous fluid-filled cavity located on the bone. A cyst may be visible on an X-ray as a hollow growth on the bone. Although the cyst growth is not cancerous, it can weaken the surrounding bone tissue and facilitate bone fracture, according to the National Health Service in the United Kingdom. Once diagnosed, treatment for a non-neoplastic bone lesion may involve draining the cyst, then administering drugs to aid in bone healing. In cases of severe non-neoplastic bone lesions, doctors may perform a bone graft or bone marrow injection to facilitate healing.
Benign
Some types of bone lesions form tumors, and benign bone lesions are non-cancerous tumors. During the development of a benign lesion, bone cells begin to proliferate uncontrollably and form an abnormal growth on the affect bone, but the tumor has little ability to invade other tissues. These lesions can typically be detected on an X-ray--the lesion may appear as a bony growth in cartilage, as a particularly dense region of bone, or appear similar to a cyst but with abnormal bone growths, according to the Merck Manuals Online Medical Library. Since the lesion is non-cancerous, many benign bone lesions can be removed by surgery to remove the abnormal growth, combined with reconstructive surgery to allow proper use of the bone after treatment.
Malignant
A malignant bone lesion is a cancerous growth on the bone. These growths can develop from a number of cells within the bone: from the outer bone tissue or inner bone marrow. During bone cancer development, tumor cells gain the ability to proliferate rapidly and uncontrollably, forming an abnormal growth on or in the bone. Additionally, malignant bone lesion cells have the ability to migrate into other tissue, and may begin to form additional growths on neighboring bones, or on distant tissues such as the lungs, according to the Merck Manuals Online Medical Library. Malignant bone lesions often require aggressive treatment including surgery, chemotherapy and radiation treatment.
