Monostotic fibrous dysplasia of the clivus: MRI and CT findings.

Fibrous dysplasia is a developmental disorder caused by abnormal proliferation and maturation of fibroblasts resulting in replacement of mature bone by structurally weak, immature woven bone. Clival involvement in monostotic fibrous dysplasia is extremely unusual, and has rarely been reported previously. We report a case of monostotic fibrous dysplasia of the clivus with special emphasis on the imaging findings and differential diagnosis.