Ans. is 'a' i.e., Single & grows posteriorly o Antrochoanal polyp arises from maxillary sinus and grows backward in the nose towards the choana, and can reach nasopharynx.o It is single and unilateral, i.e. it occur in one of the maxillary sinus.Antrochoanal polypo Antrochoanal polyp is non-cancerous growth arising from the mucous membrane of the maxillary sinus and reaches the opening of the sinus in the nasal cavity. It is single and unilateral, i.e. it occurs in one of the maxillary sinus. It arises from maxillary sinus and grows backward in the nose towards the choana and may reach the nasopharynx. Generally occurs in young age group (children and young adults) and is more common in male. Exact etiology is not known, However sinus infection has been incriminated (in contrast to ethmoidal polyp, which is considered as allergic).Clinical features of antrochoanal polypo Unilateral Nasal blockage (more on expiration than on inspiration)o Obstruction may become bilateral when polyp grows into nasopharynx and starts obstructing opposite choana.o Hyponasal voiceo Mucoid nasal dischargeo Conductive deafness due to eustachian tube dysfunctiono On examination polyp may not be visible on anterior rhinoscopy as it grows posteriorlyo On posterior rhinoscopy - smooth, greyish white, spherical mass is seen in choana.Treatment of antrochoanal polypo There is no medical treatment for antrochoanal polyp. The treatment of choice is complete surgical removal of polyp along with removal of lining of maxillary sinus to prevent the recurrence. Surgeries for antrochoanal polyp includeAvulsion of a polypThe stalk of the polyp is grasped and gently moved around to tease out the antral lining.Most of the time, avulsion fails to remove the polyp and antral lining completely.Intranasal polypectomyIt was the treatment of choice for all age groups prior to the advent of endoscopic sinus surgery and is still the treatment of choice in those setups where endoscopic surgery is not practised.Caldwell Luc operationIt is indicated if there is a recurrence and the age of the patient is more than 17 years.Now a days with FESS available - Caldwell luc operation is avoided.Functional endoscopic sinus surgery (FESS)This is the treatment of choice for all polyps, whenever available and has superceded other methods of polyp removal.