Sinonasal polyps are among the most frequent complications of sinusitis and among the most common ndings in patients undergoing sinus surgery.They are formed by expansion of uid in the deep lamina propria of the sinonasal Schneiderian mucosa and are the most common expansile lesions in the nasal cavity. Polyps have been associated with multiple causes including infectious rhinosinusitis, cystic brosis, aspirin intolerance, and allergic fungal sinusitis. Sinonasal polyposis is considered a predictor
of poorer surgical outcome, and surgical fail- ure rates as high as 75% have been reported
in patients with extensive sinonasal polyposis before surgery. Recurrent polyposis is seen in 29.9%–40% of patients undergoing revision FESS.
On CT images, polyps are usually homoge- neous soft-tissue masses with smooth convex borders and may be single or multiple. As they enlarge, they may ll a sinus and go on to remodel or even destroy adjacent bony structures.