polyp

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Related to Peutz-Jeghers syndrome: Lynch syndrome, Turcot syndrome

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 ?
LKB1exonic and whole gene deletions are a common cause of Peutz-Jeghers syndrome. J Med Genet 2006;43:e18.
Peutz-Jeghers Syndrome. Diagnostic and therapeutic approach.
The present study has evaluated endoscopic ultrasound (EUS) for screening in high-risk individuals: 13 with FAMMM families, 21 with familial pancreatic cancer, three with hereditary pancreatitis, two with Peutz-Jeghers syndrome, five with BRCA1 and BRCA2 mutations and one Li-Fraumeni syndrome.
(4) Peutz-Jeghers syndrome is also associated with protein-losing gastroenteropathy.
Peutz-Jeghers syndrome with "adenoma malignum" of the cervix: a report of two cases.
Peutz-Jeghers syndrome is an autosomal dominant disorder with familial occurrence of gastrointestinal hamartomatous polyps in association with mucocutaneous hyperpigmentation and occurs in approximately 1 in 8300 to 280,000 live births (1, 2).
To the Editor: Peutz-Jeghers syndrome (PJS) is an autosomal dominant inherited disease, characterized by mucocutaneous pigmentation and hamartomatous gastrointestinal polyps.
2) Peutz-Jeghers syndrome due to mutations in the STK11 tumor suppressor gene (very rare, but a very strong risk factor).
Endoscopic examination showed multiple sessile jejunal polyps, which on histologic examination showed features of hamartoma suggestive of Peutz-Jeghers Syndrome.
The most known causative genes for genetic CRC that have been cloned and characterized within the past decade are those with polyps like familial adenomatous polyposis FAP, AFAP, juvenile polyposis, Peutz-Jeghers syndrome, Cowden syndrome and with no polyps (hereditary Nonpolyposis CRC, HNPCC).
(3) Brown or dark pigmentation or discoloration of the gingival tissue is however considered as multifactorial, including genetic factors, tobacco use, systemic disorders (endocrine disturbance, Albright's syndrome, malignant melanoma, Peutz-jeghers syndrome, hemochromatosis, Addison's syndrome and von Recklinghausen's disease), antimalarial drugs, heavy metals (silver, bismuth, mercury, lead), zidovudine, amalgam tattoo, nevus, melanoacanthoma, kaposis sarcoma.
Muehrcke's lines have also been described in a patient with Peutz-Jeghers syndrome, (13) as well as in a heart transplant recipient.