Fibrous Dysplasia of the Temporal Bone: a Demanding Entity for Radiologists and ENT Surgeons.

Fibrous dysplasia (FD) is a rare, benign, chronic, slowly progressive bone disorder characterized by the replacement of normal bone and bone marrow by fibrous tissue, leading to deformity, pain and functional impairment. It was considered a disease of unknown etiology, uncertain pathogenesis and diverse histopathology. It was later discovered that was caused by a non-heritable activating mutation in the á-subunit gene of the stimulatory G-protein coding gene.