A patient with antrochoanal polyp (Killian's polyp) undergoes FESS for definitive treatment. Unlike simple nasal polyps arising from the ethmoid, antrochoanal polyps arise from which specific location and have which characteristic feature on CT?

• A Arising from the ethmoid sinus; bilateral in 60% of cases
• B Arising from the inferior turbinate mucosa; never extending into sinuses
• C Arising from the sphenoid sinus; associated with AFRS
• D Arising from the maxillary sinus antrum, with a bilobed appearance — one lobe in the sinus, one in the nasal cavity extending through the ostium to the choana ✓

Explanation

Antrochoanal polyp (Killian's polyp) arises from the mucosa of the maxillary sinus antrum, exits through an accessory ostium in the posterior fontanelle of the middle meatus, and extends as a bilobed mass — one lobe within the maxillary antrum and a second lobe in the nasal cavity extending posteriorly to the choana and sometimes into the nasopharynx. On CT, this bilobed configuration (sinus + nasal/nasopharyngeal component) is characteristic. It is typically unilateral, occurs in young adults, and requires complete removal including the sinus component through a middle meatal antrostomy to prevent recurrence.

Reference: Dhingra Diseases of Ear, Nose and Throat, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.