Craniofacial fibrous dysplasia is a bone disease of the face and skull that replaces normal bone with fibrous-type tissue. This tissue is not as hard as normal bone, and because it is soft and stringy, it makes the bone more fragile and prone to break. Craniofacial fibrous dysplasia may cause shifting of facial features and facial asymmetry, such as incorrect placement of the eyes, misalignment of the jaw, and other problems. Fibrous dysplasia may appear in childhood, usually between the ages of 3 and 15. Boys are more often affected. Surgical treatment is usually required