Fibrous dysplasia can affect any bone in your body. Most people with the disorder have only one affected bone — a form called monostotic fibrous dysplasia — and develop no signs or symptoms. When the condition affects more than one bone, it's known as polyostotic fibrous dysplasia. Bones most commonly affected are:

  • Thighbone (femur)
  • Shinbone (tibia)
  • Pelvic bones
  • Ribs
  • Skull
  • Facial bones
  • Upper arm bone (humerus)

Fibrous dysplasia may cause few or no signs and symptoms, particularly if the condition is mild. Signs and symptoms typically develop during the teens or 20s. If you have the polyostotic form, you're more likely to develop signs and symptoms, usually by age 10. More severe fibrous dysplasia may cause:

  • Bone pain
  • Difficulty walking
  • Bone deformities
  • Fractures

In rare cases, fibrous dysplasia may be associated with abnormalities in the hormone-producing glands of your endocrine system — such as your pituitary gland — that regulate various functions throughout your body. These abnormalities include:

  • Very early puberty (precocious puberty). Girls with McCune-Albright syndrome may experience menstrual bleeding and other signs of puberty before age 8. Boys with the condition may show signs of puberty at a younger age than normal, but early puberty in boys is less common than it is in girls.
  • Thyroid gland problems. This small gland in the neck, which affects metabolism, may be enlarged or have cysts.
  • Skin discoloration. Patches of darker skin, known as cafe au lait spots, appear light coffee colored on fairer children, but may be difficult to see on children with darker skin.

When to see a doctor

See your doctor if you or your child:

  • Develops bone pain
  • Has difficulty walking
  • Fractures a bone, particularly more than once
  • Develops a deformity in a limb or a difference between limb lengths

If you or your child has been diagnosed with fibrous dysplasia, see your doctor if the pain:

  • Worsens
  • Increases with weight-bearing activity
  • Wakes you up at night
  • Doesn't go away with rest
  • Causes you to limp
Jul. 07, 2011