Fibrous dysplasia (FD) is a rare disease caused by a sporadic genetic mutation that generates a disruption in the maturation of bone mesenchyme. We report a 27 year old male patient, with a history of nasal septum fracture and frontal region pain associated with nausea, and walking disability for eight years. At the physical examination we found craniofacial asymmetry, decreased visual acuity, and bilateral deafness. Brain magnetic resonance imaging revealed hyperostosis and decreased volume of brain volume, cerebellum, and sinuses. Skeletal survey revealed diffuse enlargement of the bone marrow component and polyostotic involvement. Diagnosis of polyostotic fibrous dysplasia bone was based on clinical and imaging data. The diagnosis of this patient was late. It has been reported that in young patients FD is diagnosed by radiological methods, rarely requiring bone biopsy.