Antrochoanal polyp

The antrochoanal polyp, usually a solitary benign growth, arises from the maxillary antrum of a non-allergic patient. It grows by extension from the antrum through its ostium into the middle meatus, then goes into the posterior choana and may extend into the nasopharynx. Antrochoanal polyps are known to otolaryngologists and have been frequently reported in the otolaryngologic literature after Killian’s excellent description in 1906.1 In the radiologic literature, the antrochoanal polyp has been largely ignored. Since it has unique features which help radiologist to reach diagnosis. Similar, less common, polyps can arise in the sphenoid sinus extending into the nasopharynx: these are termed sphenochoanal polyps. Likewise, there are nasochoanal, frontochoanal, and ethmochoanal polyps.