This somewhat unconventional parasagittal reformat of a paranasal sinus CT shows a lobulated soft-tissue density mass protruding into the lower nasal cavity from above (click image for arrows). The sphenoid and ethmoid sinuses can be seen to be opacified, and the bones thinned. The image is taken medial to the conchae, and represents a true nasal cavity lesion. Coronal images show opacification of maxillary and ethmoid sinuses, and expansion and thinning of the ethmoid bones. The patient is 67 years old and presented with 1 year of nasal stuffiness. The findings are typical of sinonasal polyposis.

Sinonasal polyposis is a chronic inflammatory condition characterized by multiple giant polyps filling the sinuses and nasal cavity. When severe, bone thinning and remodelling is common. It is associated with asthma, allergy, cystic fibrosis and aspirin insensitivity. Treatment is with intranasal steroids and endoscopic sinus surgery. Recurrence is common.

Reference: Harnsberger R, et al. Head and Neck: Top 100 Diagnoses. Amirsys 2002

Credit: Dr Laughlin Dawes