The primary tool for diagnosis of fibrous dysplasia is an X-ray. While bone appears solid in an X-ray, a fibrous dysplasia lesion has a relative distinct appearance often described as "ground glass." The condition may be diagnosed, therefore, even in a person with no symptoms who is getting an X-ray for other reasons.

An X-ray can also help your doctor determine how much of the bone is affected and whether there is any deformity in the bone.

Additional tests may be used to confirm a diagnosis or rule out other disorders:

  • Imaging tests. Computerized tomography and magnetic resonance imaging can produce cross-sectional or 3-D images of bone. These tools can help your doctor better characterize the quality of bone or a fracture associated with fibrous dysplasia.
  • Bone scan. A bone scan is a nuclear imaging test. A small amount of radioactive tracer is injected into your bloodstream and taken up by damaged portions of bone. When your body is scanned with a specialized camera, the images can help a doctor identify multiple fibrous dysplasia lesions.
  • Biopsy. This test uses a hollow needle to remove a small piece of the affected bone for microscopic analysis. The structure and arrangement of cells can confirm a fibrous dysplasia diagnosis.