polyp

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Related to polyposis: polyposis coli, Intestinal polyposis

polyp,

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.
The Columbia Electronic Encyclopedia™ Copyright © 2013, Columbia University Press. Licensed from Columbia University Press. All rights reserved. www.cc.columbia.edu/cu/cup/
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Polyp

 

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.


Polyp

 

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.

REFERENCES

See references under COELENTERATA.

D. V. NAUMOV

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.

polyp

[′päl·əp]
(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).
(medicine)
A smooth, rounded or oval mass projecting from a membrane-covered surface.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

polyp

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
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
References in periodicals archive ?
Based on a retrospective analysis of 153 patients who underwent FESS for nasal polyposis with a minimum follow-up of 7 years, we aimed to: (1) determine the prevalence of long-term mucocele development, (2) search for potential statistical relationships with various variables, and (3) analyze the management and ultimate outcome of this long-term complication.
Clinical aspects of patients with nasal polyposis. Intl Arch Otorhinolaryngol 2009; 13(3): 259-63.
This study revealed that endoscopic sinus surgery for nasal polyposis is a safe and simple procedure.
However, we were strict in our definition of synchronous polyposis, thus increasing specificity to our definition of polyposis.
(10) Agnifili et al studied 271 patients with both solitary and juvenile polyposis across 12 countries, and found 13 cases of solitary juvenile polyp with neoplastic changes.
However, according to our present results, the ABO and RhD blood group systems are not linked with development of nasal polyposis. To the best of our knowledge, no study on this topic was published.
Increased colorectal cancer risk during follow-up in patients with hyperplastic polyposis syndrome: a multicentre cohort study.
Portal Hypertensive Polyposis. Apart from the expected cirrhosis-related pathologies such as esophagogastric varices and portal hypertensive gastropathy, there was a noticeable high prevalence of gastroduodenal polyposis observed in our patients.
Intra-abdominal desmoid tumors are more commonly seen in patients with familial adenomatous polyposis. While sporadic desmoids more commonly present as an extra-abdominal mass [6, 7].
The excised right-sided lesion was stringy with a smooth yellow surface and lobular appearance (Figure 2a), and the excised left-sided masses had typical appearances of nasal polyposis (Figure 2b).
Results: There were 116 patients with documented diagnosis of nasal polyposis. Among these, 75 (64.7%) were male and 41 (35.3%) were female patients.