Fibrous Dysplasia

  • What is fibrous dysplasia?

    Fibrous dysplasia is a bone disease that destroys normal bone and replaces it with bone tissue that is not hard like normal bone. Instead, it is fibrous, which means it is soft and stringy making it more fragile and prone to break. Fractures occur in about 50 percent of patients with fibrous dysplasia.

    One or more bones can be affected by the disease. The long bones, such as the femur (thigh bone), and the bones of the face and skull are most often affected. When the condition affects the bones in the face and skull, it may also cause shifting of facial features and facial asymmetry.

    Fibrous dysplasia occurs in childhood, usually between the ages of 3 and 15. Boys are more often diagnosed with fibrous dysplasia than girls, except for one specific type of fibrous dysplasia – McCune-Albright Syndrome – which is more common in girls.

    There are two forms of fibrous dysplasia:

    • Monostotic, which is active while the child is growing but often becomes inactive after puberty
    • Polystotic, which remains active throughout a person’s life

    Patients with fibrous dysplasia have an increased risk of developing malignant tumors such as osteosarcoma, fibrosarcoma, chondrosarcoma and malignant fibrous histiocytoma. However, that increased risk is very low, with tumors only occurring in about 1 percent of people with fibrous dysplasia.

  • Causes

    The cause of fibrous dysplasia is unknown. Researchers have, however, determined it is not passed from parents to their children.

  • Symptoms

    Symptoms of fibrous dysplasia can include:

    • Bone fractures or bone deformities
    • Bone pain
    • Bone sores or lesions which may stop when the child reaches puberty
    • Difficulty walking
    • Endocrine gland problems
    • Unusual skin color (lighter and darker spots on the skin)
    • Painless growth or lump on the face that increases in size, causing facial asymmetry
    • Shifting or incorrect placement of the eyes
    • Gradually shifting face structure, which leads to facial asymmetry
    • Nasal airway obstruction caused by shifting bones in the oral and nasal passages
    • Shifting of the bite, causing it to become misaligned (malocclusion), which can make it difficult to chew and swallow
    • Shifting facial bones can lead to compression on nerves exiting the skull, such as the optic nerve or acoustic nerve, which can cause visual and hearing problems 
  • Diagnosing fibrous dysplasia

    At The Children’s Hospital of Philadelphia (CHOP), your child’s diagnostic evaluation begins with a thorough medical history and physical exam.

    Clinical experts use a variety of tests to diagnose fibrous dysplasia, including:

    • Radioisotope bone scan, which can help locate an area of abnormal bone growth.
    • Magnetic resonance imaging, which uses a combination of large magnets, radiofrequencies and a computer to produce detailed images of organs and structures within the body.
    • Computed tomography (CT) scan, which uses a combination of X-rays and computer technology to produce cross-sectional images ("slices") of the body. The diagnosis of facial fibrous dysplasia is often confirmed with CT scan.
    • X-rays, which produce images of bones and internal organs on film.
    • EOS imaging, an imaging technology that creates 3-dimensional models from two planar images. Unlike a CT scan, EOS images are taken while the child is in an upright or standing position, enabling improved diagnosis due to weight-bearing positioning.
    • Endocrine screening, which tests hormone levels.
  • Treatment

    At CHOP, treatment of fibrous dysplasia is based on your child’s symptoms and results of diagnostic testing.

    Nonsurgical Treatment

    In some cases, fibrous dysplasia can be treated with a class of drugs called bisphosphonates, which prevent bone loss and can reduce pain.

    Surgical Treatment

    If the thigh bone is fractured due to fibrous dysplasia, surgical treatment is almost always necessary.

    Though surgery for fibrous dysplasia is highly effective, we understand that any surgery can be a stressful experience for your child and family. At CHOP, we offer a wealth of resources about how to prepare your child for surgery and what to expect during surgery.

    Additionally, we employ numerous best practices before, during and after surgery to decrease the risk of infection and increase positive outcomes. See safety in surgery for details about safety protocols at The Children's Hospital of Philadelphia.

    Surgical treatment for fibrous dysplasia consists of:

    • Intralesional curettage, which involves scraping out the bone to completely remove the tumor  and filling the space with material such as methyl methacrylate cement or diluted phenol.
    • Intramedullary nails, which are metal rods placed in a bone to provide additional support to make activity possible earlier and encourage healing.

    After surgery for fibrous dysplasia, your child should expect to stay overnight in the Hospital.

    If your child has progressive fibrous dysplasia affecting the facial bones, several options are available. CHOP’s Craniofacial Program and plastic surgeons specialize in caring for children with facial fibrous dysplasia.

    • If the affected areas of the face are small and easily accessible, treatment usually involves complete surgical removal (resection) of the area and reconstruction using a combination of bone grafts and materials such as titanium plates and screws.
    • If the area affected is too large or too important to be removed, the size of the bone may be reduced using a surgical tool called a bur.
    • If the fibrous dysplasia is in an area where it is growing and compressing nerves, removing some of the surrounding bone can decompress the nerve.
    • In severe cases where the jaw is displaced and malocclusion occurs, a procedure called an osteotomy may be performed to reposition the jaw.

    Your child may need additional surgeries over the course of treatment for fibrous dysplasia. In severe cases, the excess bone may grow back over time and require repeated treatments.

    Surgery is usually done through limited incision approaches and hidden incisions in the hair. This can help reduce visible scarring. Depending on the complexity of the surgery required, your child may be hospitalized anywhere from one to several days.

    If surgery is required on a particular facial region such as the skull base, a neurosurgeon, plastic surgeon, and ophthalmologist may work together to ensure the most effective treatment.

  • Follow-up care

    At The Children's Hospital of Philadelphia, we offer ongoing support and services for your child and family at our Main Campus and throughout our CHOP Care Network. Our team is committed to partnering with parents and referring physicians to provide the most current, comprehensive and specialized care for your child.

    If your child had surgical treatment for fibrous dysplasia, he or she will return for check-ups one to two weeks after surgery, then again at three months, six months, one year and two years post-surgery.

    Follow-up is important in fibrous dysplasia to prevent deformities as a result of the disease and check for recurrence. In 50 percent of cases, fibrous dysplasia will recur.

    During follow-up visits, your child’s physician will likely perform a physical exam and order X-rays of the affected area until your child reaches skeletal maturity. Your child may also be referred to an endocrinologist for periodic testing of any thyroid abnormalities.

    If your child is diagnosed with McCune-Albright syndrome, a subset of fibrous dysplasia, your child will also be monitored for any spine curvatures such as scoliosis.

  • Outlook

    Outcomes for children treated for fibrous dysplasia at CHOP have been excellent. Because the disease often recurs, continued clinical monitoring is extremely helpful in long-term management of the condition.

Reviewed by Alexandre Arkader, MD, Scott P. Bartlett, MD on September 30, 2015