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Related to antrochoanal polyp: inverted papilloma


in medicine, a benign tumor occurring in areas lined with mucous membrane such as the nose, gastrointestinal tract (especially the colon), and the uterus. Some polyps are pedunculated tumors, i.e., they grow on stems; others, attached by a broad base, are called sessile. Nasal polyps are usually associated with an allergic condition; since they interfere with breathing, it is advisable that they be removed. Uterine and gastrointestinal polyps are likely to cause bleeding, but, more important, they may undergo malignant degeneration and for this reason are also usually removed.



a morbid growth that develops on mucosa of the respiratory tract, uterus, stomach, large intestine, rectum, and urinary bladder. Polyps are villous formations of various shapes; sometimes pear-shaped, they are usually broad-based or pedunculated. They may ulcerate and cause hemorrhages. Modern medical practice considers polyps precancerous, and therefore they are surgically removed.



the common name for the predominantly benthic form of coelenterates. In metagenetic forms, that is, in hydrozoans (except hydras) and scyphozoans, polyps are capable only of vegetative reproduction, forming either medusae (in hydrozoans by budding, in scyphozoans by transverse division) or other polyps. Sexual reproduction is characteristic in such forms only in individuals of the medusa phase—free-swimming individuals or individuals remaining attached to the polyp. In homogenetic forms (hydrida and anthozoans), the polyps are capable of both sexual and vegetative reproduction. With sexual reproduction, larvae develop from the eggs and are transformed into polyps.

Polyps usually are cylindrical and measure from several millimeters to several centimeters tall (rarely up to 1 m). The upper part of the body contains the mouth, which is surrounded by tentacles. The base serves as a foot by which the polyp attaches itself to the substrate (in solitary forms) or to the colony (in colonial forms). There is often a hard external or internal skeleton of organic matter or limestone. The nervous system, which is developed considerably less than in the medusa, is in the form of a subepithelial nerve ganglion. Sex glands are present only in homogenetic forms and are located in the ectoderm (in Hydrida) or in the entoderm (in anthozoans). Sexual products are eliminated through ruptures in the walls of the gonads. In rare cases (in some actiniae), development occurs in the gastral cavity of the maternal body.

Polyps, except for hydras and a few related forms, are marine organisms. The majority lead a sedentary life; many form colonies. Movements are limited by the extension and contraction of the body and tentacles. Some solitary forms, hydras and actiniae, move slowly along the substrate; a few actiniae inhabit the depths. Polyps feed predominantly on animal substances, usually capturing their prey with their tentacles.


See references under COELENTERATA.



(invertebrate zoology)
A sessile cnidarian individual having a hollow, somewhat cylindrical body, attached at one end, with a mouth surrounded by tentacles at the free end; may be solitary (hydra) or colonial (coral).
A smooth, rounded or oval mass projecting from a membrane-covered surface.


1. Zoology one of the two forms of individual that occur in coelenterates. It usually has a hollow cylindrical body with a ring of tentacles around the mouth
2. Pathol a small vascularized growth arising from the surface of a mucous membrane, having a rounded base or a stalklike projection
References in periodicals archive ?
The primary symptoms of antrochoanal polyps are nasal obstruction, rhinorrhea, epistaxis, postnasal drip, and snoring.
An antrochoanal polyp can be successfully removed via endoscopic transnasal excision.
Choanal and antrochoanal polyps are often unilateral, and inverted papilloma should always be included in the differential diagnosis.
To the best of our knowledge, no case of a sphenochoanal polyp with concomitant obstructive sleep apnea has been reported, and only 2 cases (13,14) of an antrochoanal polyp with obstructive sleep apnea have been reported.
Antrochoanal polyp presenting with obstructive sleep apnea and cachexia, Int J Pediatr Otorhinolaryngol 2000;54:163-6.
Patients with an antrochoanal polyp often present with unilateral nasal obstruction, but if the polyp extends into the nasopharynx, bilateral obstruction may occur.
An antrochoanal polyp typically appears as a smooth, gray or bluish intranasal mass that arises from the ipsilateral maxillary sinus.
The 29 complications in the GESS group occurred in 13 patients without polyps, 16 with nasal polyps, and 0 with antrochoanal polyps.
The 2 GESS patients with antrochoanal polyps who answered the survey both indicated that their symptoms had improved.
Antrochoanal polyps exit through the maxillary ostium and pass between the middle turbinate and the lateral nasal wall to reach the choana.
Sources cited by Yanagisawa et al in this month's Rhinoscopic Clinic state that antrochoanal polyps account for what percentage of all nasal polyps?