(redirected from Polyps)
Also found in: Dictionary, Thesaurus, Medical.


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 ?
Factors associated with malignancy in hysteroscopically resected endometrial polyps: a systematic review and meta-analysis.
The efficacy and safety of Dupixent by injection were established in two studies with 724 patients aged 18 years and older with chronic rhinosinusitis (prolonged inflammation of the sinuses and nasal cavity) with nasal polyps (growths on the inner lining of the sinuses) who were symptomatic despite taking intranasal corticosteroids.
The co-primary endpoints of POLYP 1 and POLYP 2 were change from baseline in Nasal Polyp Score (NPS) and change from baseline in average daily Nasal Congestion Score (NCS) over 24 weeks.
It has been reported that hyperplastic polyps are the most common type especially at the areas where Helicobacter pylori infection is common.
All consecutive patients with suspected colorectal serrated polyps who underwent endoscopic treatment at the Digestive Endoscopy Centers of The Sixth People's Hospital of Nantong and Huai'an First People's Hospital, between January 2014 and May 2018, were investigated.
Pathological examination showed that one of the tubular adenoma polyps exhibited high-grade dysplasia, while the remaining exhibited low-grade dysphasia.
Evaluation and Management of Antrochoanal Polyps. Clin Exp Otorhinolaryngol.
In artificial symbiotic algae transmission experiments, Rahat and Reich (1986) fed isolated symbiotic algae to Artemia larvae, and then the larvae were fed to non-symbiotic hydra polyps. Rahat and Sugiyama (1993) fed freshly hatched Artemia larvae to non-symbiotic hydra polyps, and then immediately gave the feeding polyps concentrated suspensions of isolated symbiotic algae in order to make an artificial transmission.
(11) Vocal fold polyps are noncancerous growths on the vocal cords that cause hoarseness by disrupting the glottal closure and vibration pattern.
reported 1 of 331 juvenile polyps had adenomatous change and adenocarcinoma in situ.