NASAL POLYPOSIS 59 in size because of the oedema within it, and it passes posteriorly towards the choana and enters the nasopharynx. Here it enlarges to fill the nasopharynx, and as greater growth occurs the polypus then grows forward through the nasal cavity of the original side, and thus becomes bilobed (Fig. 25). It resembles the ordinary nasal polypus in structure. SYMPTOMS. A naso-antral polypus is more commonly found in childhood or adolescence than in adult life. There is a complaint of unilateral nasal Fig. 25. Naso-antral polypus showing stalk of attachment and bilobed appearance. (Reproduced by permission ofBailliere Tindallfrom 'The Ear Nose and Throat Diseases of Children'.) obstruction which becomes bilateral as the polypus fills the nasopharynx. A mucoid discharge is noted, again unilaterally at first and later bilaterally. The voice becomes affected and hyponasality develops. Snoring may be complained of initially. There is no pain, nor is there earache, but deafness may be present because of the occlusion of the auditory tubes. CLINICAL FEATURES. Anterior rhinoscopy in the early stages may reveal no abnormality, although there may be accumulated mucus on the floor of the nasal cavity of the obstructed side. It may occasionally be possible to see the polypus far back in the nasal cavity. When the polypus becomes bilobed it will be seen with increasing ease. Posterior rhinoscopy is not always easy to perform in the young, but when it is successful a smooth, greyish-white, spherical mass will be seen hi the choana early on, and later filling the nasopharynx (Plate II, 4). Once the nasopharynx is filled the polypus may project below the soft palate, or may be seen when the palate rises on phona- tion. It presents as a greyish convex mass on examining the pharynx. Radio- graphy will show a lack of air entry into the affected maxillary sinus, while a lateral projection will demonstrate the polypoid swelling in the nasopharynx. TREATMENT. This is essentially surgical. A small polypus may be snared off in the same way as a nasal polypus if the snare wire can be passed round the polypus hi the choana. When the choanal polypus is fully developed it is easier to avulse it under endotracheal anaesthesia. The main mass in the nasopharynx is grasped with forceps and steady traction will avulse the growth from the accessory ostium, and the polypus is removed completely.