Fronto-orbital sphenoethmoidal fibrous dysplasia

Abstract

Cranial fibrous dysplasias (FDs) are rare and comprise less than 1% of all primary bone lesions. They may produce cosmetic deformities, peripheral compressive cranial neuropathies, and compressive central neurologic manifestations. We describe an unusual presentation of a fronto-orbital sphenoethmoidal FD in a 32-year-old woman with conventional radiographic, CBCT, and MRI findings. In the head and neck examination, an asymmetry was noticed on the left side, without evidence of adenopathy, paresthesia, or motor nerve deficiency. Panoramic radiographs showed a radiopaque expanded bone in the region of the posterior maxillary sinus and orbita. Computed tomography with three-dimensional reconstruction demonstrated an expanding lesion of the cranial bones, involving the ethmoid and periorbital bone, producing a ground-glass appearance. After the radiologic examination, the patient was referred for surgery with a diagnosis of cranial FD and underwent a cranioplasty. The CT and MRI features were typical for FD, but physicians and dental professionals should be aware of this diagnosis, even if no symptom is apparent and the patient came in only for a routine dental examination. Maxillofacial radiologists should also consider that the signal intensity on both T1- and T2-weighted images and the degree of contrast enhancement on T1-weighted images depend on the amount and degree of bony trabeculae, cellularity, collagen, and cystic and hemorrhagic changes.