In gastroenterology

Gastroenterology

Gastroenterology is the branch of medicine whereby the digestive system and its disorders are studied. The name is a combination of three Ancient Greek words gaster , enteron , and logos...

, a sessile serrated adenoma (abbreviated SSA), also known as sessile serrated polyp (abbreviated SSP), is a premalignant flat (or sessile) lesions of the colon

Colon (anatomy)

The 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...

, predominantly seen in the cecum

Cecum

The cecum or caecum is a pouch, connecting the ileum with the ascending colon of the large intestine. It is separated from the ileum by the ileocecal valve or Bauhin's valve, and is considered to be the beginning of the large intestine. It is also separated from the colon by the cecocolic...

 and ascending colon

Ascending colon

The ascending colon is smaller in caliber than the cecum.It passes upward, from its commencement at the cecum, opposite the colic valve, to the under surface of the right lobe of the liver, on the right of the gall-bladder, where it is lodged in a shallow depression, the colic impression; here it...

.

SSAs are thought to lead to colorectal cancer

Colorectal cancer

Colorectal cancer, commonly known as bowel cancer, is a cancer caused by uncontrolled cell growth , in the colon, rectum, or vermiform appendix. Colorectal cancer is clinically distinct from anal cancer, which affects the anus....

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

APC (gene)

Adenomatous polyposis coli also known as deleted in polyposis 2.5 is a protein that in humans is encoded by the APC gene. Mutations in the APC gene may result in colorectal cancer....

.

Microscopy

SSAs are characterized by:

• basal dilation of the crypts,
• basal crypt serration,
• crypts that run horizontal to the basement membrane (horizontal crypts), and
• crypt branching.

Unlike traditional colonic adenoma

Adenoma

An adenoma is a benign tumor of glandular origin. Adenomas can grow from many organs including the colon, adrenal glands, pituitary gland, thyroid, prostate, etc. Although these growths are benign, over time they may progress to become malignant, at which point they are called adenocarcinomas...

s (e.g. tubular adenoma, villous adenoma

Villous adenoma

Villous adenoma is a type of polyp that grows in the colon and other places in the gastrointestinal tract and sometimes in other parts of the body. These adenomas may become malignant . Villous adenomas have been demonstrated to contain malignant portions in about one third of affected persons,...

), they do not (typically) have nuclear changes (nuclear hyperchromatism, nuclear crowding, elliptical/cigar-shaped nuclei).

See also

• Polyp table
• Colonic polyps
• Colorectal polyps
• Colorectal carcinoma
• Microsatellite instability
  Microsatellite instability
  Microsatellites are repeated sequences of DNA. Although the length of these microsatellites is highly variable from person to person, each individual has microsatellites of a set length. These repeated sequences are common, and normal...
  
  

External links

• Intestinal adenomas - halflytely.com.