I have an eight year old grandson with Fibrous Dysplasia. His parents are both very athletic and it has been a shock to find out that their son has such a little known and disabilitating disease. I fear for him and pray for his safety daily. A fall. Another child pushing him hard enough. So many possible catastraphes every day is enough to drive you insane when it is your child at risk of possible surgeries or worse. ~ Sandi
Fibrous DysplasiaFibrous dysplasia is a chronic condition of the skeleton where a portion of a bone develops abnormally.
The condition begins before birth. It is caused by a gene mutation that affects the cells that produce bone. Although the abnormal bone forms before birth, its presence is often not discovered until childhood, adolescence, or even adulthood.
Fibrous dysplasia in the upper thighbone. Left, An X-ray of the area. Right, A magnetic resonance image of the same area.
Fibrous dysplasia accounts for approximately 7% of all benign bone tumors. Any bone may be affected. The most common bones involved are the thighbone, shinbone, ribs, skull, upper arm bone, and pelvis.
Usually, only one bone is involved (monostotic fibrous dysplasia). Less often, multiple bones are involved (polyostotic fibrous dysplasia). The polyostotic form is generally more severe and is discovered earlier. This form can involve as few as two bones in the same limb or multiple bones throughout the skeleton.
The same abnormality that occurs in the bone cells of fibrous dysplasia may also occur in the cells of some of the body's glands. This can lead to hormonal abnormalities. This is rare and generally only happens with severe forms of polyostotic fibrous dysplasia. McCune-Albright syndrome is a condition where polyostotic fibrous dysplasia occurs with pigmented skin lesions ("cafe au lait" spots) and hormonal abnormalities.
Fibrous dysplasia in the upper thighbone. This X-ray shows a fracture at tip of arrow.
Severe deformity can lead to loss of vision or hearing when facial bones are involved. When the leg and pelvis bones are severely deformed, arthritis may develop in nearby joints.
Young patients with hormonal abnormalities may develop early puberty. This problem is more common in girls than boys. This is usually caused by overactivity of the ovaries. Overactivity may also occur in other glands of the body, including:
- the thyroid gland (causing anxiety, loss of weight, and abnormal sweating)
- the adrenal glands (causing weight gain, diabetes)
- the pituitary gland (causing milk production in women, gigantism, acromegaly)
- the parathyroid glands (causing high levels of calcium in the blood)
The elevated hormone levels normally associated with pregnancy may speed up the growth of fibrous dysplasia lesions, causing increased pain.
Warning signs that an area of fibrous dysplasia may have become cancerous include increasing pain, particularly pain that wakes you up at night or does not go away with rest. The presence of a mass should always be investigated.
A doctor can usually diagnose fibrous dysplasia based in part on x-rays. The x-rays may show:
- An abnormal area of bone that typically has an appearance similar to that of ground glass
- Frequently, expansion of the involved area of bone
- Deformity of the bone that is usually seen as bowing
Fibrous dysplasia in the shinbone with bowing. Left, Side view X-ray shows the area of dysplasia. Center, Magnetic resonance image (MRI) of the same area, showing the dysplasia. Right, Cross-sectional MRI of the area, showing the dysplasia.
Bone scan of fibrous dysplasia in the shinbone with bowing. A bone scan will show a "hot spot" in the areas of involved bone. A bone scan is a good test to check the entire skeleton for areas of fibrous dysplasia.
If a fracture is present, it will generally be seen on x-ray and/or MRI. A computed tomography (CT) scan may help the doctor to see fractures and determine the weakness of the bone.
Fibrous dysplasia in the upper arm (humerus). Left, An X-ray showing fibrous dysplasia. Center, magnetic resonance image of the same area. Right, X-ray of the same bone one year later with a fracture (at tip of arrow).
Areas of fibrous dysplasia can rarely become cancerous. This occurs in less than one half of 1% of patients. With McCune-Albright syndrome, this may occur in 4% of patients. If cancer occurs, the x-ray will generally show areas of bone destruction. MRI may show an associated mass in the surrounding tissues.
Fibrous dysplasia in the hip socket with a fracture. Left, An X-ray of the area. Center, computed tomography of the same area. Right, Bone scan.
A thighbone with typical findings of fibrous dysplasia. Left, X-ray with typical findings. Right, The same bone 5 years later with areas of typical fibrous dysplasia (red arrow) and an area of cancer (yellow arrow).
Fibrous dysplasia is a chronic disorder. It is often progressive. Although lesions may stabilize and stop growing, they do not disappear. Individual lesions may progress more rapidly in the polyostotic form and in growing children.Observation. Areas of fibrous dysplasia that are not symptomatic may be observed with periodic x-rays and not treated if they are not progressing. Braces may occasionally be used to prevent fracture, but they have not been effective in preventing deformity.
Medications. Bisphosphonates are medications that decrease the activity of cells that dissolve bone. They have recently become available in easy to take oral forms. These medications have not been used extensively in the treatment of fibrous dysplasia, but early studies have demonstrated effective relief of the pain associated with fibrous dysplasia.
Surgical treatment is often necessary. The following findings are associated with the need for surgery.
- Symptomatic lesions that have not responded to nonsurgical treatment
- Displaced fractures (when the bone breaks into two or more separate pieces)
- Hairline cracks that do not heal with casting or bracing
- Progressive deformity
- Presence of cancer
- As a means to prevent large lesions from causing a fracture
Shows an X-ray of the lesion from Figure 1 after curettage, bone grafting, and fixation with a metal plate and screws.
Additionally, scooping out (curettage) of the fibrous dysplasia is generally performed along with bone grafting. Over time, the bone graft placed in the defect often is absorbed and replaced with more fibrous dysplasia.
An X-ray with fibrous dysplasia in both the pelvis and upper thighbone, or femur (arrows). Metal rods have been placed in the thighbone to prevent fracture.
Newer generations of medications, like the bisphosphonates, have made them easier to take with fewer side effects. More experience with these medications may allow more effective treatment.