A case of monostotic fibrous dysplasia of the maxillary sinus.

Fibrous dysplasia is an uncommon benign disease of the bone, with slow progression. Monostotic involvement of the paranasal sinuses is rare. We report a 54-year-old woman who had complaints of facial asymmetry, chronic sinusitis, recurrent headaches, and nasal obstruction for two years. Conventional radiography showed opacification and expansion of the maxillary sinus. Axial and coronal computed tomography scans showed a heterogeneous mass that expanded the right maxillary sinus, leading to nasal obstruction and cortical thickening of the maxilla. No signs of destruction or erosion in the cortical bone were identified. An endonasal endoscopic biopsy was performed and the diagnosis of fibrous dysplasia was confirmed histologically.