Fibrous dysplasia

Overview

Fibrous dysplasia (FD) is a condition where normal bone is replaced by scar–like tissue, making the affected areas more prone to fractures. This rare skeletal disease can damage one, multiple, or the entire skeleton.

Fibrous dysplasia can happen to any bone. Monostotic FD refers to the occurrence of this condition in one bone, polyostotic FD if it affects multiple bones, and panostotic FD if it involves all bones in the body.  Fibrous dysplasia does not spread from one bone to another and is rarely cancerous.

Bones that are mostly affected by FD include facial bones, pelvis, ribs, shinbone (tibia), skull, thighbone (femur), upper arm bone (humerus), and vertebrae in the spine. Symptoms may include bone pain and deformity, bone fractures, and scoliosis. Treatment options may include medication and surgery.

Symptoms

The symptoms of FD can range from minor to severe. The symptoms may vary for every person. Some people may not exhibit any signs or symptoms at all.

Occasionally, fibrous dysplasia manifests as one component of a cluster of conditions termed McCune–Albright syndrome. This syndrome impacts bones, endocrine tissues responsible for hormone production, and the skin.

This syndrome results in a variety of symptoms, including café–au–lait spots on the skin and the early onset of puberty. 

Common signs and symptoms of FD include:

• Bone fractures 
• Bone deformity 
• Extreme tiredness, especially in young children
• Weakness and bone pain in the afflicted area
• Scoliosis, or a sideways curve of the spine
• A waddling walk
• Endocrine–related issues, such excessive growth hormone production, an overactive thyroid, and early puberty

Symptoms may appear not related to the bones, these symptoms come with FD:

• Loss of vision or hearing if certain nerves are squeezed as a result of the fibrous bone tissue
• Bulging eyes, nasal congestion, and uneven jaws if FD affects facial bones

Cause

The exact cause of fibrous dysplasia is unknown. It is believed to be caused by a chemical flaw in a particular bone protein. Although the illness is not known to run in families, this deficiency may be caused by a gene mutation that was present at birth. The mutation must have occurred in one gene that controls bone growth and development.

Risk factors

Fibrous dysplasia can occur in anyone at any age. However, majority of the cases are diagnosed among children ages 3 to 15. Both men and women are also equally affected by it. The bone defect is thought to manifest in childhood but may go undiscovered unless there is pain associated with it, a limp appears, or a fracture occurs. This condition has no relation to any ethnicity or region.