Legend Axial T2WIs and Coronal T1WI show large region of signal void at the posterior ethmoid sinus, extending into and having a mass effect on the left medial posterior orbit, displacing the medial rectus muscle and the left optic nerve laterally. Integrity of the medial wall of the right orbit cannot be assured.

Legend Post contrast Axial and Coronal T1WIs with fat saturation show no enhancement within the region of signal void. No abnormal enhancement is noted in other structures.

Legend NECT Coronal images show a homogeneous and very dense mass. There is slight remodeling of the left medial orbital roof which is expanded slightly superiorly. Extension into the bilateral ethmoid sinus, sphenoid sinus and the left maxillary sinus is also seen. Mucus retention cyst is present in the left maxillary sinus. Key words: mri ct bone tumor sinus orbit neoplasia

ENT Diagnosis: Osteoma of ethmoid sinus