Fibrous Dysplasia FD of bone is a rare non-inheritable congenital disease characterized by a focal proliferation of fibrous tissue in the bone marrow leading to osteolytic lesions deformities and fractures. FD can be presented in a monostotic or polyostotic form this last one is usually more severe. FD primarily affects adolescents and young adults and in some cases in an asymptomatic way. We describe the case of a male patient with long evolution form of polyostotic fibrous dysplasia of bone with delayed clinical presentation. It is also highlighted the importance of an activity and involvement form evaluation as well as possible endocrine abnormalities associated in order to establish the correct treatment and prognosis.