Sphenoid Sinus Mucocele

Fig. 1: Axial unenhanced CT image shows opacification of the left sphenoid sinus due to a mass (arrow) causing slight expansion of the sinus. Some parts of the sinus wall are thin and some are thick.
Fig. 2: Coronal T2W GRE MR image show the mass to be very hyperintense. There was no contrast enhancement (image not shown).

Facts: Mucocele of Paranasal Sinus

• Most common expansile lesions of the paranasal sinuses
• Most common location = frontal, ethmoid
• Chronic, cystic lesion of the paranasal sinuses, lined by respiratory epithelium
• Results of obstruction of sinus ostium, causing accumulation of secretions into an expanding mass
• Contents are sterile. If it becomes infected, it is called mucopyocele
• Can be seen in any age group, commonly relapsed

Imaging Findings

• Complete sinus opacification
• Bone remodeling, expansion and thinning/thickening of the wall
• On fluid-sensitive MR sequence, it is very bright
• Differential diagnosis: mucus retention cyst (usually not filled the whole sinus and no expansion), polyp (common in nasal cavity)

Reference

Rollers CA. Mucocele of the paranasal sinuses. Available at URL: http://www.bcm.edu/oto/grand/05252000.html