A sessile serrated lesion (SSL) is a

premalignant A precancerous condition is a condition, tumor or lesion involving abnormal cells which are associated with an increased risk of developing into cancer. Clinically, precancerous conditions encompass a variety of abnormal tissues with an increase ...

flat (or sessile) lesion of the colon, predominantly seen in the

cecum The cecum ( caecum, ; plural ceca or caeca, ) is a pouch within the peritoneum that is considered to be the beginning of the large intestine. It is typically located on the right side of the body (the same side of the body as the appendix (a ...

and

ascending colon In the anatomy of humans and homologous primates, the ascending colon is the part of the colon located between the cecum and the transverse colon. Characteristics and structure The ascending colon is smaller in calibre than the cecum from wh ...

. SSLs are thought to lead to

colorectal cancer Colorectal cancer (CRC), also known as bowel cancer, colon cancer, or rectal cancer, is the development of cancer from the Colon (anatomy), colon or rectum (parts of the large intestine). Signs and symptoms may include Lower gastrointestinal ...

through the (alternate) ''serrated pathway''. This differs from most colorectal cancer, which arises from mutations starting with inactivation of the

APC gene Adenomatous polyposis coli (APC) also known as deleted in polyposis 2.5 (DP2.5) is a protein that in humans is encoded by the ''APC'' gene. The APC protein is a negative regulator that controls beta-catenin concentrations and interacts with E- ...

. Multiple SSLs may be part of the ''

serrated polyposis syndrome Serrated polyposis syndrome (SPS), previously known as hyperplastic polyposis syndrome, is a disorder characterized by the appearance of serrated polyps in the colon. While serrated polyposis syndrome does not cause symptoms, the condition is asso ...

''.

Signs and symptoms

SSLs are generally asymptomatic. They are typically identified on a

colonoscopy Colonoscopy () or coloscopy () is a medical procedure involving the Endoscopy, endoscopic examination of the large bowel (colon) and the distal portion of the small bowel. This examination is performed using either a Charge-coupled device, CCD ...

and excised for a definitive diagnosis and treatment.

Serrated polyposis syndrome

The serrated polyposis syndrome (SPS) is a relatively rare condition characterized by multiple and/or large serrated polyps of the colon. Serrated polyps include SSLs, hyperplastic polyps, and traditional serrated adenomas. Diagnosis of this disease is made by the fulfillment of any of the World Health Organization's (WHO) clinical criteria.

Diagnosis

SSLs are diagnosed by their microscopic appearance; histomorphologically, they are characterized by (1) basal dilation of the crypts, (2) basal crypt serration, (3) crypts that run horizontal to the basement membrane (horizontal crypts), and (4) crypt branching. The most common of these features is basal dilation of the crypts. Unlike conventional colonic

adenoma An adenoma is a benign tumor of epithelium, epithelial tissue with glandular origin, glandular characteristics, or both. Adenomas can grow from many glandular organ (anatomy), organs, including the adrenal glands, pituitary gland, thyroid, prosta ...

s (e.g. tubular adenoma, villous adenoma), they do not (typically) have

nuclear Nuclear may refer to: Physics Relating to the nucleus of the atom: *Nuclear engineering *Nuclear physics *Nuclear power *Nuclear reactor *Nuclear weapon *Nuclear medicine *Radiation therapy *Nuclear warfare Mathematics * Nuclear space *Nuclear ...

changes (nuclear hyperchromatism, nuclear crowding, elliptical/cigar-shaped nuclei). Image:Sessile serrated adenoma 3 low mag.jpg, Low magnification

micrograph A micrograph is an image, captured photographically or digitally, taken through a microscope or similar device to show a magnify, magnified image of an object. This is opposed to a macrograph or photomacrograph, an image which is also taken ...

of an SSL. Image:Sessile serrated adenoma 3 intermed mag.jpg, Intermediate magnification micrograph of an SSL. Image:Sessile serrated adenoma 2 high mag.jpg, High magnification micrograph of a SSL showing crypt branching.

Treatment

Complete removal of a SSL is considered curative. Several SSLs confer a higher risk of subsequently finding

and warrant more frequent surveillance. The surveillance guidelines are the same as for other

colonic Colon cleansing, also known as colon therapy, colon hydrotherapy, a colonic, or colonic irrigation, encompasses a number of alternative medical therapies claimed to remove toxins from the colon and intestinal tract by removing accumulations o ...

s. The surveillance interval is dependent on (1) the number of adenomas, (2) the size of the adenomas, and (3) the presence of high-grade microscopic features.

Epidemiology

Sessile serrated lesions account for about 25% of all serrated polyps. Advanced SSLs with cytological dysplasia are rare in younger patients, and progression of SSLs appears to be linked with ageing.

History

Sessile serrated adenomas were first described in 1996. In 2019, the World Health Organization recommended the use of the term "sessile serrated ''lesion''," rather than sessile serrated ''polyp'' or ''adenoma''.

References

External links

Pathology of Serrated Colon Adenomas
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{{Digestive system neoplasia Digestive system neoplasia Histopathology