Extensive fibrous dysplasia of skull base: case report.

Abstract

Fibrous dysplasia (FD) is a skeletal developmental anomaly in which normal medullary bone is replaced by fibrous tissue. FD has two major forms: monostotic, involving a single bone and polyostotic, having multiple lesions involving multiple bones. The monostotic form can be clinically silent and diagnosis is made usually after puberty but patients in the second-third decades can also be asymptomatic; the polyostotic form is usually diagnosed before puberty [1]. The clinical picture is variegated, connected to the location of the lesions. FD manifests as one or more slowly enlarging, painless bony masses and may potentially involve any bone in the body. Lesions can become quite disfiguring and can lead to functional impairment. Deformity is progressive and there may be impingement on other structures and functional impairment due to mass effect. These lesions are structurally weak and therefore prone to pathologic fracture or to be associated to other disease process of the bone [2]. Clivus and skull base FD is a rare and relative unknown entity; correct diagnosis is essential to distinguish between different diseases affecting the cranial base and to plan the proper management.