Growths that develop under the skin, which seem to be connected to the bones, could be bone tumors. These growths form when tissue such as cartilage begins to grow excessively, forming masses of bone and tissue. Like all tumors, they can be either malignant or benign. Malignant tumors are cancerous and can spread throughout the body. Benign bone tumors generally remain in one place and are only fatal if the growth inhibits other bodily functions.
The majority of bone tumors develop on the distal femur and the proximal tibia; in other words, the thigh bone and the area around the joint of the knee. If the tumor forms in or near the joint, a person might feel stiffness or a dull ache at the location. Many bone tumors form during growth phases and can exist for a person’s entire life without causing problems.
Osteochondromas are the most common type of benign bone tumor, making up about 35% to 40% of all cases. The growths usually appear near the ends of bones that are actively growing, such as the arms and legs. As such, the condition is most often seen in children and teenagers. Osteochondromas tend to grow on flat bones such as the pelvis and the shoulder blades. About three percent of the general population have an osteochondroma.
There are many different types of bone tumors besides osteochondromas:
Benign bone tumors may not cause symptoms, and a person may never know they have one. If the growth is large enough, however, it may be visible underneath the skin. Tumors can also weaken bone, which may lead to fractures from minor injuries and intense pain. If the tumor develops near a nerve, it may exert pressure as it grows, causing numbness or tingling that could require treatment.
The exact causes of bone tumors are not known. Experts suspect genetics, bone injuries, and radiation treatment can all play a role. The tumors usually form when specific parts of the body grow rapidly. Bone fractures repaired with metal implants also seem more likely to develop tumors. Recently, studies show having multiple osteochondromas indicates a dominantly inherited disease, which suggests other benign bone tumors may also be hereditary.
Beyond pain and the feeling of a mass under the skin, most benign bone tumors do not have a major effect on a person’s life. However, even though they are benign, the tumors may become malignant and lead to cancer. They may also continue to grow and could compress healthy bone tissue.
Typically, the doctor will perform a scan such as an x-ray or MRI. The scan can highlight growths and inform the doctor exactly where the tumor is and how much of the bone is affected. In some cases, the doctor may wish to take a sample of the tumor or the marrow from the affected bone to perform a biopsy. This is usually part of the removal surgery, though it can be done before as well if the physician needs more information.
Benign bone tumors are treated similarly to malignant ones. In some cases, the tumor may fracture, leading to self-resolution. Some tumors may need surgical removal involving bone grafts or skeletal regeneration. If doctors fear the tumor may turn malignant, they may recommend chemotherapy or radiotherapy. Cryosurgery, which freezes the tumor from the inside, has been successful recently.
Surgery to remove a benign bone tumor is generally safe and straightforward, but complications can develop. These can include minor issues such as stiffness and bleeding. More serious issues, such as nerve injury and infection, can be dangerous. After the surgery, there is a small chance the tumor may return. The location of the tumor could pose some difficulty for the surgeon, and sometimes the doctor must remove pieces instead of the entire mass.
Most people with benign bone tumors lead perfectly normal lives. Those who have them removed have a risk of recurrence or complications. Ultimately, it depends on the size and location of the tumor and the age of the patient, but dangers due to benign bone tumors are rare. For example, osteochondromas have less than a one percent chance of becoming malignant.
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