A
polyp is an abnormal growth of tissue projecting from a
mucous membraneThe mucous membranes are linings of mostly endodermal origin, covered in epithelium, which are involved in absorption and secretion. They line cavities that are exposed to the external environment and internal organs...
. If it is attached to the surface by a narrow elongated
stalkPedicle or pedicel may refer to:*Pedicle of vertebral arch, the segment between the transverse process and the vertebral body, and is often used as a radiographic marker and entry point in vertebroplasty and kyphoplasty procedures...
, it is said to be
pedunculatedIn medicine and zoology, a peduncle is a stalk-shaped mass of tissue. Pedunculated is a term that is used to describe a mass that has or is supported on a peduncle, such as a cyst or polyp.As opposed to sessile which lacks a stalk- References :*...
. If no stalk is present, it is said to be
sessileIn medicine, sessility is a characteristic of tumors and polyps that lack a stalk, as opposed to those that are pedunculated....
. Polyps are commonly found in the
colonThe colon is the last part of the digestive system in most vertebrates; it extracts water and salt from solid wastes before they are eliminated from the body, and is the site in which flora-aided fermentation of unabsorbed material occurs. Unlike the small intestine, the colon does not play a...
,
stomachThe stomach is a muscular, hollow, dilated part of the alimentary canal which functions as an important organ of the digestive tract in some animals, including vertebrates, echinoderms, insects , and molluscs. It is involved in the second phase of digestion, following mastication .The stomach is...
,
noseThe visible part of the human nose is the protruding part of the face that bears the nostrils. The shape of the nose is determined by the ethmoid bone and the nasal septum, which consists mostly of cartilage and which separates the nostrils...
,
sinus(es)Paranasal sinuses are a group of four paired air-filled spaces that surround the nasal cavity , above and between the eyes , and behind the ethmoids...
,
urinary bladderThe urinary bladder is the organ that collects urine excreted by the kidneys before disposal by urination. A hollow muscular, and distensible organ, the bladder sits on the pelvic floor...
and
uterusThe uterus or womb is a major female hormone-responsive reproductive sex organ of most mammals including humans. One end, the cervix, opens into the vagina, while the other is connected to one or both fallopian tubes, depending on the species...
. They may also occur elsewhere in the body where mucous membranes exist like the
cervixThe cervix is the lower, narrow portion of the uterus where it joins with the top end of the vagina. It is cylindrical or conical in shape and protrudes through the upper anterior vaginal wall...
and
small intestineThe small intestine is the part of the gastrointestinal tract following the stomach and followed by the large intestine, and is where much of the digestion and absorption of food takes place. In invertebrates such as worms, the terms "gastrointestinal tract" and "large intestine" are often used to...
.
A
polyp is an abnormal growth of tissue projecting from a
mucous membraneThe mucous membranes are linings of mostly endodermal origin, covered in epithelium, which are involved in absorption and secretion. They line cavities that are exposed to the external environment and internal organs...
. If it is attached to the surface by a narrow elongated
stalkPedicle or pedicel may refer to:*Pedicle of vertebral arch, the segment between the transverse process and the vertebral body, and is often used as a radiographic marker and entry point in vertebroplasty and kyphoplasty procedures...
, it is said to be
pedunculatedIn medicine and zoology, a peduncle is a stalk-shaped mass of tissue. Pedunculated is a term that is used to describe a mass that has or is supported on a peduncle, such as a cyst or polyp.As opposed to sessile which lacks a stalk- References :*...
. If no stalk is present, it is said to be
sessileIn medicine, sessility is a characteristic of tumors and polyps that lack a stalk, as opposed to those that are pedunculated....
. Polyps are commonly found in the
colonThe colon is the last part of the digestive system in most vertebrates; it extracts water and salt from solid wastes before they are eliminated from the body, and is the site in which flora-aided fermentation of unabsorbed material occurs. Unlike the small intestine, the colon does not play a...
,
stomachThe stomach is a muscular, hollow, dilated part of the alimentary canal which functions as an important organ of the digestive tract in some animals, including vertebrates, echinoderms, insects , and molluscs. It is involved in the second phase of digestion, following mastication .The stomach is...
,
noseThe visible part of the human nose is the protruding part of the face that bears the nostrils. The shape of the nose is determined by the ethmoid bone and the nasal septum, which consists mostly of cartilage and which separates the nostrils...
,
sinus(es)Paranasal sinuses are a group of four paired air-filled spaces that surround the nasal cavity , above and between the eyes , and behind the ethmoids...
,
urinary bladderThe urinary bladder is the organ that collects urine excreted by the kidneys before disposal by urination. A hollow muscular, and distensible organ, the bladder sits on the pelvic floor...
and
uterusThe uterus or womb is a major female hormone-responsive reproductive sex organ of most mammals including humans. One end, the cervix, opens into the vagina, while the other is connected to one or both fallopian tubes, depending on the species...
. They may also occur elsewhere in the body where mucous membranes exist like the
cervixThe cervix is the lower, narrow portion of the uterus where it joins with the top end of the vagina. It is cylindrical or conical in shape and protrudes through the upper anterior vaginal wall...
and
small intestineThe small intestine is the part of the gastrointestinal tract following the stomach and followed by the large intestine, and is where much of the digestion and absorption of food takes place. In invertebrates such as worms, the terms "gastrointestinal tract" and "large intestine" are often used to...
.
Classification
| Polyp |
Histologic appearance |
Risk of malignancy |
Picture |
Syndromes |
| Hyperplastic |
Serrated unbranched crypts |
None |
|
Hyperplastic polyposis syndrome |
| Sessile serrated adenoma In gastroenterology, a sessile serrated adenoma , also known as sessile serrated polyp , is a premalignant flat lesions of the colon, predominantly seen in the cecum and ascending colon....
|
Similar to hyperplastic with hyperserration, dilated/branched crypt base, prominent mucin cells at crypt base |
|
|
|
| Inflammatory |
Raised mucosa/submucosa with inflammation |
If dysplasia develops |
|
Inflammatory Bowel Disease In medicine, inflammatory bowel disease is a group of inflammatory conditions of the colon and small intestine. The major types of IBD are Crohn's disease and ulcerative colitis.-Classification:...
, ulcers, infections, mucosal prolapse |
| Tubular Adenoma (Villous, Tubulovillous) |
Tubular glands with elongated nuclei (at least low-grade atypia) |
Yes |
|
|
| Traditional Serrated Adenoma |
Serrated crypts, often villous architecture, with cytologic atypia, eosinophilic cells |
Yes |
|
|
| Peutz-Jeghers Polyp |
Smooth muscle bundles between nonneoplastic epithelium, "Christmas tree" appearance |
No |
|
Peutz–Jeghers syndrome |
| Juvenile Polyp |
Cystically dilated glands with expanded lamina propria |
Not inherently, may develop dysplasia |
|
Juvenile polyposis syndrome Juvenile polyposis syndrome is a syndrome characterized by the appearance of multiple polyps in the gastrointestinal tract, usually in a child, adolescent or young adult. Polyps refers to a growth arising from the lumen of the colon or stomach...
, identical polyps in Cronkhite-Canada syndrome |
| Hamartomatous Polyp (Cowden Syndrome) |
Variable; classical mildly fibrotic polyp with disorganized mucosa and splaying of muscularis mucosae; also inflammatory, juvenile, lipoma, ganglioneuroma, lymphoid |
No |
|
Cowden syndrome Cowden syndrome is a rare autosomal dominant inherited disorder characterized by multiple tumor-like growths called hamartomas and an increased risk of certain forms of cancer....
|
| Inflammatory fibroid polyp Inflammatory fibroid polyp, abbreviated IFP, is a benign abnormal growth of tissue projecting into the lumen of the gastrointestinal tract.-Pathology:...
|
Spindle cells with concentric arrangements of spindle cells around blood vessels and inflammation rich in eosinophils |
none |
|
|
Colorectal polyp
Colon polyps are not commonly associated with symptoms. Occasionally
rectal bleedingLower gastrointestinal bleeding, commonly abbreviated LGIB, refers to any form of bleeding in the lower gastrointestinal tract. LGIB is a common ailment seen at emergency departments. It presents less commonly than upper gastrointestinal bleeding . It is estimated that UGIB accounts for 100-200 per...
, and on rare occasions
painPain is an unpleasant sensation often caused by intense or damaging stimuli such as stubbing a toe, burning a finger, putting iodine on a cut, and bumping the "funny bone."...
,
diarrheaDiarrhea , also spelled diarrhoea, is the condition of having three or more loose or liquid bowel movements per day. It is a common cause of death in developing countries and the second most common cause of infant deaths worldwide. The loss of fluids through diarrhea can cause dehydration and...
or
constipationConstipation refers to bowel movements that are infrequent or hard to pass. Constipation is a common cause of painful defecation...
may occur because of colon polyps. Colon polyps are a concern because of the potential for colon cancer being present microscopically and the risk of
benignBenignity [from Latin benignus , from bonus + genus ] is a medical term used to describe a condition that is harmless...
colon polyps transforming over time into malignant ones. Since most polyps are asymptomatic, they are usually discovered at the time of colon cancer screening with either
digital rectal exam (DRE)A rectal examination or rectal exam is an internal examination of the rectum such as by a physician or other healthcare professional.-Procedure:...
,
flexible sigmoidoscopySigmoidoscopy From Greek Sigma - eidos - scopy, to look inside an s-like object, is the minimally invasive medical examination of the large intestine from the rectum through the last part of the colon. There are two types of sigmoidoscopy, flexible sigmoidoscopy, which uses a flexible endoscope,...
,
Barium enemaA lower gastrointestinal series, also called a barium enema, is a medical procedure used to examine and diagnose problems with the human colon . X-ray pictures are taken while barium sulfate fills the colon via the rectum.-Procedure:...
,
colonoscopyColonoscopy is the endoscopic examination of the large bowel and the distal part of the small bowel with a CCD camera or a fiber optic camera on a flexible tube passed through the anus. It may provide a visual diagnosis and grants the opportunity for biopsy or removal of suspected...
or
virtual colonoscopyVirtual colonoscopy is a medical imaging procedure which uses x-rays and computers to produce two- and three-dimensional images of the colon from the lowest part, the rectum, all the way to the lower end of the small intestine and display them on a screen...
. The polyps are routinely removed at the time of colonoscopy either with a polypectomy snare (first description by P. Deyhle, Germany, 1970) or with biopsy forceps. If an adenomatous polyp is found with flexible sigmoidoscopy or if a polyp is found with any other diagnostic modality, the patient must undergo colonoscopy for removal of the polyp(s). Even though colon cancer is usually not found in polyps smaller than 2.5 cm, all polyps found are removed since the removal of polyps reduces the future likelihood of developing colon cancer. When adenomatous polyps are removed, a repeat colonoscopy is usually performed in three to five years.
Most colon polyps can be categorized as sporadic.
Inherited polyposis syndromes
- Familial adenomatous polyposis
Familial adenomatous polyposis is an inherited condition in which numerous polyps form mainly in the epithelium of the large intestine. While these polyps start out benign, malignant transformation into colon cancer occurs when not treated....
- Peutz-Jeghers syndrome
Peutz–Jeghers syndrome, also known as hereditary intestinal polyposis syndrome, is an autosomal dominant genetic disease characterized by the development of benign hamartomatous polyps in the gastrointestinal tract and hyperpigmented macules on the lips and oral mucosa...
- Turcot syndrome
Mismatch repair cancer syndrome is a condition associated with biallelic DNA mismatch repair mutations. It is also known as Turcot syndrome after Jacques Turcot who described the condition in 1959.-Genetics:...
- Juvenile polyposis syndrome
Juvenile polyposis syndrome is a syndrome characterized by the appearance of multiple polyps in the gastrointestinal tract, usually in a child, adolescent or young adult. Polyps refers to a growth arising from the lumen of the colon or stomach...
- Cowden disease
- Bannayan-Zonana syndrome
Bannayan–Riley–Ruvalcaba syndrome is a rare hamartomatous disorder with occurrence of multiple subcutaneous lipomas, macrocephaly and hemangiomas...
- Gardner's syndrome
Gardner syndrome, also known as familial colorectal polyposis, is an autosomal dominant form of polyposis characterized by the presence of multiple polyps in the colon together with tumors outside the colon...
Types of colon polyps
- Malignant
- Hamartomatous
- Hyperplastic
- Inflammatory
Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process...
Endometrial polyp
An endometrial polyp or uterine polyp is a polyp or
lesionA lesion is any abnormality in the tissue of an organism , usually caused by disease or trauma. Lesion is derived from the Latin word laesio which means injury.- Types :...
in the lining of the uterus (
endometrium-Function:The endometrium is the innermost glandular layer and functions as a lining for the uterus, preventing adhesions between the opposed walls of the myometrium, thereby maintaining the patency of the uterine cavity. During the menstrual cycle or estrous cycle, the endometrium grows to a...
) that takes up space within the uterine cavity. Commonly occurring, they are experienced by up to 10% of women. They may have a large flat base (
sessileIn medicine, sessility is a characteristic of tumors and polyps that lack a stalk, as opposed to those that are pedunculated....
) or be attached to the uterus by an elongated
pediclePedicle or pedicel may refer to:*Pedicle of vertebral arch, the segment between the transverse process and the vertebral body, and is often used as a radiographic marker and entry point in vertebroplasty and kyphoplasty procedures...
(
pedunculatedIn medicine and zoology, a peduncle is a stalk-shaped mass of tissue. Pedunculated is a term that is used to describe a mass that has or is supported on a peduncle, such as a cyst or polyp.As opposed to sessile which lacks a stalk- References :*...
). Pedunculated polyps are more common than sessile ones. They range in size from a few millimeters to several centimeters. If pedunculated, they can protrude through the
cervixThe cervix is the lower, narrow portion of the uterus where it joins with the top end of the vagina. It is cylindrical or conical in shape and protrudes through the upper anterior vaginal wall...
into the
vaginaThe vagina is a fibromuscular tubular tract leading from the uterus to the exterior of the body in female placental mammals and marsupials, or to the cloaca in female birds, monotremes, and some reptiles. Female insects and other invertebrates also have a vagina, which is the terminal part of the...
. Small blood vessels may be present in polyps, particularly large ones.
Cervical polyp
A cervical polyp is a common
benignA benign tumor is a tumor that lacks the ability to metastasize. Common examples of benign tumors include moles and uterine fibroids.The term "benign" implies a mild and nonprogressive disease. Indeed, many kinds of benign tumors are harmless to human health...
polyp or
tumorA tumor or tumour is commonly used as a synonym for a neoplasm that appears enlarged in size. Tumor is not synonymous with cancer...
on the surface of the
cervical canalIn the anatomy of the female reproductive system, the canal of the cervix is the spindle-shaped, flattened canal of the cervix, the neck of the uterus.It communicates with the uterine cavity via the internal orifice of the uterus, and with the vagina via the...
. They can cause irregular
menstrualMenstruation is the shedding of the uterine lining . It occurs on a regular basis in sexually reproductive-age females of certain mammal species. This article focuses on human menstruation.-Overview:...
bleeding or increased pain but often show no symptoms. Treatment consists of simple removal of the polyp and prognosis is generally good. About 1% of cervical polyps will show neoplastic change which may lead to
cancerCancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
. They are most common in post-
menstrualMenstruation is the shedding of the uterine lining . It occurs on a regular basis in sexually reproductive-age females of certain mammal species. This article focuses on human menstruation.-Overview:...
, pre-
menopausalMenopause is a term used to describe the permanent cessation of the primary functions of the human ovaries: the ripening and release of ova and the release of hormones that cause both the creation of the uterine lining and the subsequent shedding of the uterine lining...
women who have given birth.
Adenomatous polyps
Adenomatous polyps, or adenomas, are polyps that grow on the lining of the colon and which carry a high risk of
cancerCancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
. The adenomatous polyp is considered pre-malignant, i.e. likely to develop into colon cancer. The other types of polyps that can occur in the colon are the hyperplastic and inflammatory polyps. They are unlikely to develop into colorectal cancer.
About 50% of people aged 60 will have at least one adenomatous polyp of 1 cm diameter or greater. Multiple adenomatous polyps often result from familial polyposis coli or familial adenomatous polyposis, a condition that carries a very high risk of colon cancer.
Adenomas constitute approximately 10% of polyps. Most polyps (approximately 90%) are small, usually less than 1 cm in diameter, and have a small potential for malignancy. The remaining 10% of adenomas are larger than 1 cm and approach a 10% chance of containing invasive cancer.
There are three types of adenomatous polyp:
- Tubular adenomas are the most common of the adenomatous polyps; they may occur everywhere in the colon and they are the least likely colon polyps to develop into colon cancer;
- Tubulovillous
- Villous adenomas are commonly found in the rectal area and they are normally larger in size than the other two types of adenomas. They tend to be nonpedunculated, velvety, or cauliflowerlike in appearance and they are associated with the highest morbidity and mortality rates of all polyps. They can cause hypersecretory syndromes characterized by hypokalemia
Hypokalemia or hypokalaemia , also hypopotassemia or hypopotassaemia , refers to the condition in which the concentration of potassium in the blood is low...
and profuse mucousIn vertebrates, mucus is a slippery secretion produced by, and covering, mucous membranes. Mucous fluid is typically produced from mucous cells found in mucous glands. Mucous cells secrete products that are rich in glycoproteins and water. Mucous fluid may also originate from mixed glands, which...
discharge and can harbor carcinoma in situCarcinoma in situ is an early form of cancer that is defined by the absence of invasion of tumor cells into the surrounding tissue, usually before penetration through the basement membrane. In other words, the neoplastic cells proliferate in their normal habitat, hence the name "in situ"...
or invasive carcinoma more frequently than other adenomas.
The risks of progression to colorectal cancer increases if the polyp is larger than 1 cm and contains a higher percentage of villous component. Also, the shape of the polyps is related to the risk of progression into carcinoma. Polyps that are pedunculated (with a stalk) are usually less dangerous than sessile polyps (flat polyps). Sessile polyps have a shorter pathway for migration of invasive cells from the tumor into submucosal and more distant structures, and they are also more difficult to remove and to ascertain. Sessile polyps larger than 2 cm usually contain villous features, have a higher malignant potential, and tend to recur following colonoscopic polypectomy.
Although polyps do not carry significant risk of colon cancer, tubular adenomatous polyps may become cancerous when they grow larger. Larger tubular adenomatous polyps have an increased risk of malignancy when larger because then they develop more villous components and may become
sessileIn medicine, sessility is a characteristic of tumors and polyps that lack a stalk, as opposed to those that are pedunculated....
.
It is estimated that an individual whose parents have been diagnosed with an adenomatous polyp has a 50% greater chance to develop colon cancer than individuals with no
family historyFamily history is the systematic narrative and research of past events relating to a specific family, or specific families.- Introduction :...
of colonic polyps. At this point, there is no method to establish the risks that patients with a family history of colon polyps have to develop these growths. Overall, nearly 6% of the population, regardless of the family history, is at risk to developing colon cancer.
Screening for colonic polyps as well as preventing them has become an important part of the management of the condition. The
American Cancer SocietyThe American Cancer Society is the "nationwide community-based voluntary health organization" dedicated, in their own words, "to eliminating cancer as a major health problem by preventing cancer, saving lives, and diminishing suffering from cancer, through research, education, advocacy, and...
has established guidelines for colorectal screening in order to prevent adenomatous polyps and to minimize the chances of developing colon cancer. It is believed that some changes in the diet might be helpful in preventing polyps from occurring but there is no other way to prevent the polyps from developing into cancerous growths than by detecting and removing them.
According to the guidelines established by the American Cancer Society, individuals who reach the age of 40 should perform an occult blood test yearly. The colon polyps, as they grow might cause
bleedingBleeding, technically known as hemorrhaging or haemorrhaging is the loss of blood or blood escape from the circulatory system...
within the
intestineIn human anatomy, the intestine is the segment of the alimentary canal extending from the pyloric sphincter of the stomach to the anus and, in humans and other mammals, consists of two segments, the small intestine and the large intestine...
which can be detected with the help of this test. Also, persons in their 50s are recommended to have flexible sigmoidoscopies performed once in 3 to 5 years to detect any abnormal growth which could be an adenomatous polyp. If adenomatous polyps are detected during this procedure, it is most likely that the patient will have to undergo a
colonoscopyColonoscopy is the endoscopic examination of the large bowel and the distal part of the small bowel with a CCD camera or a fiber optic camera on a flexible tube passed through the anus. It may provide a visual diagnosis and grants the opportunity for biopsy or removal of suspected...
. However, colonoscopies are recommended by many physicians as an important part of screening for colon cancer as they provide an accurate image of the intestine and also allow the removal of the polyp, if found. Once an adenomatous polyp is identified during colonoscopy, there are several methods of removal including using a snare or a heating device. Colonoscopies are advised to be performed every 10 years in individuals who reached the age of 50 and who do not suffer from colonic polyps or cancer. Colonoscopies are preferred over sigmoidoscopies because they allow the examination of the entire colon, a very important aspect considering that more than half of the colonic polyps occur in the upper colon which is not reached during sigmoidoscopies.
It has been statistically demonstrated that screening programs are effective in reducing the number of deaths caused by colon cancer due to adenomatous polyps. Yet, although these tests are almost 100% safe, their use is still controversial because of the complications that might arise. However, most of the specialists agree that the benefits of colorectal screening overcome the risks. The risk of complications arising from colonoscopies is half the risk of developing colon cancer. As there is a small likelihood of recurrence, surveillance after polyp removal is recommended.
External links