Bone lesions are areas of bone that are changed or damaged. Causes of bone lesions include infections, fractures, or tumors.
When cells within the bone start to divide uncontrollably, they are sometimes called bone tumors.
Most bone lesions are benign, meaning they are not cancerous. Some bone lesions are cancerous, however, and these are known as malignant bone tumors.
Bone lesions can affect any part of the body and develop in any section of bone, from the surface to the bone marrow in the center.
They are caused by cells in the bone that start to divide and multiply uncontrollably, leading to a lump or mass of abnormal tissue.
A growing lesion can destroy healthy tissue and weaken the bone, making it more vulnerable to fractures.
Most bone lesions are benign, not life-threatening, and will not spread to other parts of the body.
Some bone lesions, however, are malignant, which means they are cancerous. These bone lesions can sometimes metastasize, which is when the cancer cells spread to other parts of the body.
Malignant bone tumors are divided into two types:
- Primary bone cancer, which is cancer that starts in the bone.
- Secondary bone cancer, which is when cancer starts somewhere else and spreads to the bone.
The cause of a bone lesion depends on whether it is benign or cancerous, in addition to other factors.
Benign bone lesions
Most bone lesions are benign, meaning they are not cancerous or life-threatening. There are also some diseases and conditions that resemble bone lesions.
Causes of benign bone lesions include:
- non-ossifying fibroma
- unicameral (simple) bone cyst
- giant cell tumor
- fibrous dysplasia
- aneurysmal bone cyst
- osteoid osteoma
If the lesion is benign, a doctor may recommend a period of monitoring with regular X-rays. Some lesions, especially those in children, may disappear over time.
Other bone lesions can be treated successfully with medications. In some cases, it may be necessary to surgically remove the lesion to reduce the risk of a bone fracture.
Benign lesions may come back after treatment. in rare cases, they may spread or become malignant.
Malignant bone tumors
Causes of malignant bone tumors or cancerous bone lesions depend on whether the cancer is primary or secondary.
The most common causes of primary bone cancer lesions are:
Multiple myeloma is a malignant tumor of the bone marrow, which is the soft tissue in the middle of bones responsible for producing blood cells.
It can affect any bone in the body and is the most common primary bone cancer, affecting about six people per 100,000 every year. Most people who get multiple myeloma are between 50 and 70 years old.
The 5-year survival rate for multiple myeloma is 50 percent. That means that just under half of people diagnosed with the condition will be alive 5 years after diagnosis.
Osteosarcoma is the second most common primary bone cancer. It is still rare, occurring in between two and five people in every million each year.
Most cases of osteosarcoma are seen either side of the knee in the thighbone or shinbone of teenagers and children. It can also sometimes occur in the hip or shoulder.
Treatment usually involves chemotherapy and surgery. The 5-year survival rate is 70 percent for children and young people with osteosarcoma in one location when they are diagnosed.
The usual treatment options for osteosarcoma are chemotherapy, surgery, and radiation.
The upper and lower leg, pelvis, upper arm, or ribs tend to be the bones affected by this type of tumor. It can also develop in the soft tissue surrounding a bone.
While Ewing sarcoma can develop at any age, more than half of those diagnosed with it are between 10 and 20 years old.
The overall 5-year survival rate for children and young people with Ewing sarcoma that has not spread is about 70 percent. If the tumor has already spread at the time of diagnosis, the prognosis is not as good.
Chondrosarcoma is a malignant tumor made up of cells that produce cartilage. It is seen mainly in people between 40 and 70 years of age. These tumors tend to develop in the hip, pelvis, or shoulder area.
Chondrosarcoma is usually treated with surgery,but the type of operation needed will depend on the stage and severity of the cancer.
During limb-sparing surgery, the affected part of the bone is removed and replaced with either a metal replacement or bone graft.
Occasionally, if the cancer cells have spread from the bone into nerves and blood vessels, the affected area may need to be amputated.
Chondrosarcoma is slow-growing cancer, and most cases are low grade when diagnosed.
Secondary bone cancer lesions
Types of cancer that begin elsewhere in the body and can spread to bone include:
In the case of secondary bone cancer that has spread from elsewhere, the treatment options and outlook will depend on the type and severity of the primary cancer.
Sometimes, bone lesions can cause pain in the affected area. This pain is usually described as dull or aching and may worsen during activity. The person may also experience fever and night sweats.
In addition to pain, some cancerous bone lesions can cause stiffness, swelling, or tenderness in the affected area. The pain may come and go and may be worse or better at night.
Not all people will experience these symptoms but may instead notice a painless mass somewhere on their body.
Bone lesions can weaken the bone tissue, making it vulnerable to fractures. Therefore, a person with a bone lesion may break a bone without having any injury.
A doctor will carry out a full physical assessment and several tests to diagnose the cause of a bone lesion. They might ask about general health, medications, and symptoms, as well as any family history of lesions or cancer.
During a physical examination, a doctor will look for swelling or tenderness, any changes in the skin, the presence of a mass, and if there is any effect on nearby joints.
They will also order imaging tests, which can include X-rays, magnetic resonance imaging (MRI) scans, or computed tomography (CT) scans.
A biopsy may also be needed to make a diagnosis. During a biopsy, a small sample of the lesion will be removed for examination under a microscope. Blood and urine tests may also be taken.
The outlook for people with a bone lesion will depend on the kind of bone lesion they have.
Benign lesions may only require watchful waiting or treatment with medications, though they may return after successful treatment.
People with malignant bone lesions will need to visit their doctor regularly, usually every few months, after treatment and be monitored for signs of recurrence.