[Fibrous dysplasia and ossifying fibroma of the base of the skull. Apropos of 6 cases].

The authors report 6 cases of fibrous dysplasia (F.D.) of the base of the skull and review the literature. They confirm the impossibility of histological differentiation between ossifying fibroma and monostic dysplasia with cranio-facial sites. They stress the value of CAT scan in the assessment of spread and that of dynamic isotope scan in the differential diagnosis with plaque-shaped hyperostotic meningioma, in the diagnosis of polyostotic forms and in postoperative surveillance. They stress the risk of visual sensorial impairment: visual by stenosis of the optic canals and auditory by stenosis of the E.A.M. Operative indications are influenced by this risk, thereby explaining the need for prolonged surveillance.