The nasal polyps occur as pedunculated lesions covered by thin mucous membrane containing a small number of lymphocytes and eosinophils, and filled with gelatinous connective tissue. They are most frequently located in the upper part of the lateral nasal wall around the middle turbinate. Nasal polyps as multiple lesions occur mostly among adults and teenagers over 14 years old. Single, unilateral polyp, so-called antral choanal polyp (ACP) comprises about 5% of nasal polyps, and occurs primarily among children and teenagers (1, 2). It contains a large amount of fibrous elements and may be considered as a tumour rather than a polyp (2). The origin of ACP is the mucous membrane of the maxillary sinus, but there have been cases describing the point of origin in the sphenoid sinus, ethmoid, and middle turbinate (3, 4). When increasing in size it extends through the semilunar hiatus into the middle meatus and elongates to the nasopharynx. Because of the ostial constriction it has two parts - one in the sinus, and the second in the nasal cavity, connected by a narrow junction. One paper reported a case of herniation of the ACP through an oroantral fistula to the oral cavity after extraction of the upper molar. ACP, much more prevalent in the paediatric population, needs special consideration because its clinical manifestations may be mimicked by conditions such as juvenile angiofibroma, meningoencephalocele, and teratoma (1). Contrary to bilateral nasal polyposis (BNP), mostly associated with allergy, where glucocorticoids and antibiotics play a dominant role in therapy (5), ACP requires surgical therapy. According to Goldman, intranasal polypectomy is not sufficient and carries a risk of recurrence (2). Antrostomy or Caldwell-Luc with extirpation of the polyp stalk is the best method to avoid recurrence.

The purpose of this study was to estimate the recurrence of ACP among children treated in the ENT Department of the Pediatric Institute by internasal polypectomy or extirpation of a polyp via the oral cavity. No Caldwell-Luc was performed because of children´s age contra-indicating this kind of operation. We also decided to measure the prevalence of ACP among children.

Twenty-six children treated in the ENT Department between 1978 and 1998 were enrolled in the study. The control group was composed of 13 children treated for BNP. Finally, 39 children were enrolled in the study. In the group with ACP there were 15 girls and 11 boys age a between 6 and 13 years (mean 9 years), while in the group with BNP (9 girls and 4 boys) the children were older at 7-17 years of age, with a mean of 11 years.

Oral extirpation was performed in the group with ACP followed by examination of the semilunar hiatus. In the group with BNP intranasal polypectomy was performed. In all cases sinusoscopy, was used to evaluate the mucous membrane, with the introduction of drains to the maxillary sinuses. In the study recurrence was noted among 8 children (30.7%) with ACP and in 2 children (15.4%) with BNP. All of them were operated on once again.

All children in the study were controlled to evaluate the condition of the upper respiratory tract. Twenty-two of 39 children answered the summons for control - 16 treated for ACP and 6 treated for BNP. Rhinoscopy, rhinometry, and x-ray of the maxillary sinuses were performed among all these children.

An allergic background was found in all controlled children from the group with BNP - they had been diagnosed for allergic rhinitis. Rhinoscopy revealed in one case a recurrence of very small polyps on both sides. There were no abnormalities in rhinometry but x-rays in all cases, showed changes from opacification to oedema of the mucous membrane of the maxillary sinuses. Among 16 controlled children from the group with ACP, two were treated for allergy. Three of them had a recurrence of the ACP during the control period (18.8% of all with ACP). These three children had rhinometry results typical of unilateral nasal obstruction, and x-rays showed total opacity of the maxillary sinus and nasal meatus on that side. Physical examination and rhinometry on the remaining children from the ACP group showed no abnormalities, while x-rays of the maxillary sinuses on the operated side revealed opacification in 2 cases (12.5%) and cyst-like changes in 6 cases (37.5%).

Antral choanal polyps are more frequent among children than bilateral nasal polyposis - 67% in the material of the study.

There is no correlation between the occurrence of antral choanal polyp and allergy among children.

Among children operated on for antral choanal polyp a tendency to recurrence is noted - 18.8% had already recurred and 50% showed changes in x-rays suggesting recurrence in the future.

In cases of antral choanal polyp operation is necessary to perform sinusoscopy to evaluate the mucous membrane, and afterwards is again necessary to introduce a drain to the maxillary sinus for irrigating the sinus.

Children operated on for antral choanal polyp must be under periodic otolaryngological control including taking x-rays. In cases of recurrence of the disease, CT should be performed and an operation appropriate to the patient´s age should be performed.