Fibrous dysplasia of the orbital region: Series of 12 cases and review of the literature.

Fibrous dysplasia (FD) is a benign fibro-osseous developmental disorder of growing bone, sometimes involving the craniofacial skeleton (CFD). We wish to present a patient series with CFD of the orbital region and discuss treatment modalities. Twelve patients were referred for orbital CFD in the Nantes University Hospital between 2000 and 2018 and studied according to the clinical parameters, radiological features, and modalities of treatment. The mean age was 25.6 years. Ten patients exhibited facial asymmetry with vertical globe dystopia (75%), proptosis (58%) and facial bump (50%). The disease was monostotic in 83% of patients, involving the frontal bone (25%), the sphenoidal bone (33%), the fronto-sphenoidal complex (25%), and the skull base (17%). Unilateral radiological proptosis was found in 7 patients, with a mean protrusion 3.9mm. The optic canal was involved in 75% of patients, with no functional impairment. Three patients were treated with bisphosphonate therapy to stop progression of the disease; 6 patients were given a bone remodelling procedure with good aesthetic outcomes. The orbit is a rare localization for FD causing aesthetic and functional disabilities. Medical and surgical treatment can be proposed as part of a multidisciplinary approach.