Fibrous dysplasia, Paget's disease of bone, and other uncommon sclerotic bone lesions of the craniofacial bones

Imaging studies of the brain, head and neck, sinuses, and dental computed tomography are among the most frequently performed procedures in radiologic departments. Systematic evaluation in the bone window may reveal common and uncommon sclerotic osseous abnormalities of the craniofacial skeleton. Most of these findings are incidental and unrelated to the initial clinical indications. Sporadically symptoms may arise due to lesional mass effect with compression on adjacent structures and neuroforaminal encroachment, resulting in proptosis, vision, or hearing loss. Other symptoms include craniofacial deformity, mandibular occlusion deformity, and local pain. This article reviews the most common disorders characterized by an increased bone density involving the craniofacial bones including fibrous dysplasia, Paget's disease of bone, meningioma with associated hyperostosis, and osteoma. Finally, typical examples of rarer sclerosing bone dysplasias are discussed as well. Emphasis is placed on imaging features and the differential diagnosis