Bone and Soft Tissue Tumors: Benign Tumors
Non-Ossifying Fibroma
On this page:
What is a non-ossifying fibroma?
What causes a non-ossifying fibroma?
What are the symptoms of a non-ossifying fibroma?
How is a non-ossifying fibroma diagnosed?
Treatment for a non-ossifying fibroma
What is the long-term outlook for a patient with a non-ossifying fibroma?
What is a non-ossifying fibroma?
A non-ossifying fibroma is one of the more common benign tumors found in children and adolescents. It consists mainly of fibrous tissue that is almost always found in a region of any of the long bones called the metaphysis (the transitional zone where the shaft of the bone joins the end of the bone). It usually occurs in the distal femur (thigh bone) or tibia (shin bone) but may also occur in the upper extremities.
These tumors usually produce no symptoms, unless a fracture is involved and usually resolve on their own at skeletal maturity (when bones normally stop growing). They very rarely persist into adulthood and never metastasize (spread). Sometimes, if the tumor weakens the bone, surgery is recommended to treat the condition.
What causes a non-ossifying fibroma?
The cause of a non-ossifying fibroma is unknown. It is believed to be a developmental defect associated with a vascular disturbance or related to a hemorrhage inside the bone.
What are the symptoms of a non-ossifying fibroma?
Typically a non-ossifying fibroma produces no symptoms, although those that are particularly large can cause chronic bone pain and/or a pathological fracture. They are often discovered by chance on X-rays.
Keep in mind that each child may experience symptoms differently depending on the size and location of the tumor. The symptoms of a non-ossifying fibroma can resemble symptoms of other medical conditions. Always consult your child's doctor for a diagnosis.
How is a non-ossifying fibroma diagnosed?
In addition to a complete medical and physical examination, the following tests are usually used to diagnose a non-ossifying fibroma:
- X-ray – a diagnostic test which uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film. An X-ray alone is usually all that is necessary to diagnose this condition.
- Computerized tomography scan (also called CT or CAT scan) – a diagnostic imaging procedure that uses a combination of X-rays and computer technology to produce cross-sectional images (often called slices) both horizontally and vertically, of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat and organs. Data obtained from this scan enables doctors to compare the density of the involved bone to the density of the corresponding unaffected bone. Doctors use this information to determine how much the fibroma is weakening the bone. It usually takes six to eight weeks before data is completely analyzed in a biomechanics laboratory and the results are known. In some instances, this information is helpful in deciding whether surgical treatment is needed.
Treatment for a non-ossifying fibroma
Specific treatment for a non-ossifying fibroma will be determined by your child's physician based on:
- your child's age, overall health, and medical history
- extent of the disease and the predicted fracture risk
- your child's tolerance for specific medications, procedures, or therapies
- how your child's physician expects the disease may progress
- your opinion or preference
This kind of tumor is neither malignant, nor aggressive, so the primary reason to treat it is to avoid a fracture, especially in athletic children. In some cases, a non-ossifying fibroma may require no treatment at all, because this condition resolves on its own over time. However, your child's orthopedic surgeon may decide that an operation is warranted if a fracture has occurred or the tumor is weakening the bone, putting it at significant risk of a fracture. This may be a very difficult decision for the parents and the surgeon. The risks of surgery and the healing and rehabilitation time must be balanced against the desire to play sports and avoid fracture. There is no right or wrong answer and the decision needs to be individualized to the child.
If an operation is recommended, the procedure of choice is usually curettage and bone grafting.
Curettage is an operation during which the tumor is scraped out of the bone with a special instrument called a curette that has a scoop, loop or ring at its tip.
For this procedure, surgeons make an incision in the bone to create a window. The tumor is completely curetted and the remaining cavity is then packed with donor bone tissue (allograft), bone chips taken from another bone (autograft), or other materials depending on the preference of the surgeon. The patient is usually placed in a cast or brace for six weeks and then can undergo protected weight bearing for another six weeks. It usually takes three to six months before a child can return to contact sports.
If a fracture is involved, the operation is put off until the fracture heals with cast immobilization followed by a period observation after it has healed. In major long bones, such as the femur, internal fixation (surgically placed metal rods and pins to fix a broken bone) may be necessary. At times, during the healing process, the tumor may heal as well.
What is the long-term outlook for a patient with a non-ossifying fibroma?
Although every patient is different, the long-term outlook for a patient with a non-ossifying fibroma is generally excellent. These tumors, as a rule, resolve on their own, usually at skeletal maturity. The concern lies in whether they will cause a fracture while active. Recurrence is rare.
