Fibrous Dysplasia is a benign condition of abnormal development where normal bone is replaced by fibrous connective tissue. As a result, the bone thins and becomes weak. In your body there are cells that constantly remodel your bones. These cells are called osteoblasts and osteoclasts. In the cartilage, there are cells called chondrocytes that build the cartilage and connective tissue and even scar tissue. In fibrous dysplasia, these cells do not function correctly.

This condition is not inherited. It can involve a single bone or multiple bones. It can occur in craniofacial bones mostly the maxilla, or in the ribs. It can be asymptomatic, or it may involve local pain and swelling or even deformity. This can cause ‘pathologic’ fractures. Depending on the location relative to the skull base, it may involve the cranial nerves.  Other signs/symptoms of cranial involvement include seizures, scalp bleeding, and darkened hair over the area. ‘

Diagnosis can be made X-ray, CT, or MRI. The lesions appear as ground glass, or thinly woven bone, where normal bone should be. While there is no definitive cure, local pain and deformity may be managed surgically.  In the case of skull involvement with compression of skull base nerves, craniotomy may be performed to remove the abnormal bone. 

Lindsey Parker PA-C and Justin F. Fraser M.D.