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).
- 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
- 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)