polyp

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

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

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.

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
References in periodicals archive ?
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).
Nasal polyposis is the ultimate manifestation of chronic inflammation.
Adults more than 12 years of age belonging to any gender having chronic rhinosinusitis with nasal polyposis (unilateral or bilateral) were included in the study.
Results: There were 116 patients with documented diagnosis of nasal polyposis.
The company's second product candidate, an Exhalation Delivery System with fluticasone propionate (OPN-375) is being developed for treatment of nasal polyposis and chronic sinusitis.
Serrated adenomatous polyposis, the term initially proposed by Torlakovic and Snover, (16) is now referred to as the serrated polyposis syndrome.
As a differential diagnosis, intestinal polyposis syndromes represent different types of FAP, including hereditary-mixed polyposis syndrome, Hamartomatous polyposis syndromes, and other variants such as Turcot syndrome.
Potack, "Colonic polyps and polyposis syndromes," in Sleisenger and Fordtrans Gastrointestinal and Liver Disease, M.
Non-multiple lymphomatous polyposis form of mantle cell lymphoma in the gastrointestinal tract.
In this case report, an eight-year old patient who was diagnosed with primary FB on open lung biopsy which was performed because of continuing complaints and lung parenchymal findings despite treatment and who developed severe nasal polyposis in the follow-up was presented.
Laryngologists estimate polyposis on the grounds of rhinoscopy with 4 degree scale, proposed in 1993 by Johansen [3]:
Prevalence of adenomas and carcinomas in the ileal pouch after proctocolectomy in patients with familial adenomatous polyposis.