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Difference between revisions of "Colon"
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[[Image:Blausen_0603_LargeIntestine_Anatomy.png|thumb|right|Anatomy of the colon and rectum. (WC)]] | [[Image:Blausen_0603_LargeIntestine_Anatomy.png|thumb|right|Anatomy of the colon and rectum. (WC)]] | ||
The '''colon''' is section of the large bowel. This article also covers the '''rectum''' and '''cecum''' as both have a similar mucosa. | The '''colon''' is section of the large bowel. This article also covers the '''rectum''' and '''cecum''' as both have a similar mucosa. | ||
It commonly comes to pathologists because there is a suspicion of [[colorectal cancer]] or a known history of [[inflammatory bowel disease]] (IBD). | It commonly comes to pathologists because there is a suspicion of [[colorectal cancer]] or a known history of [[inflammatory bowel disease]] (IBD). | ||
An introduction to gastrointestinal pathology is found in the ''[[gastrointestinal pathology]]'' article. The ''[[anus]]'' and ''[[ileocecal valve]]'' are dealt with in separate articles. | An introduction to gastrointestinal pathology is found in the ''[[gastrointestinal pathology]]'' article. The ''[[anus]]'' and ''[[ileocecal valve]]'' are dealt with in separate articles. | ||
Technically, the rectum and cecum are ''not'' part of the colon. Thus, inflammation of the rectum should be ''proctitis'' and inflammation of the cecum should be ''cecitis''. | Technically, the rectum and cecum are ''not'' part of the colon. Thus, inflammation of the rectum should be ''proctitis'' and inflammation of the cecum should be ''cecitis''. | ||
=Anatomy= | |||
*The [[rectum]] has several definition. These are discussed in the ''[[rectum]]'' article. | |||
*The large bowel may be submitted with segment names or with the distance to the anal verge. | |||
A conversion between named segments and distance - as per NCI of the United States:<ref>URL: [https://training.seer.cancer.gov/colorectal/anatomy/figure/figure1.html]https://training.seer.cancer.gov/colorectal/anatomy/figure/figure1.html]. Accessed on: 8 February 2018.</ref> | |||
{| class="wikitable sortable" | |||
!Named segment | |||
!Distance to anal verge (cm) | |||
|- | |||
|Anus | |||
|0-4 | |||
|- | |||
|[[Rectum]] | |||
|4-16 | |||
|- | |||
|Rectosigmoid | |||
|15-17 | |||
|- | |||
|Sigmoid | |||
|17-57 | |||
|- | |||
|Descending | |||
|57-82 | |||
|- | |||
|Transverse | |||
|82-132 | |||
|- | |||
|Ascending | |||
|132-147 | |||
|- | |||
|Cecum | |||
|150 | |||
|} | |||
=Common clinical problems= | =Common clinical problems= | ||
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# Subtotal colectomy - part of colon removed --or-- some of the rectum remains. | # Subtotal colectomy - part of colon removed --or-- some of the rectum remains. | ||
# Right hemicolectomy - right colon + distal ileum. | # Right hemicolectomy - right colon + distal ileum. | ||
# Lower anterior resection (LAR) - proximal rectum +/- sigmoid (for proximal rectal malignancies). | # [[Lower anterior resection]] (LAR) - proximal rectum +/- sigmoid (for proximal rectal malignancies). | ||
#* Specimens have should have intact mesorectum - ''[[total mesorectal excision]]'' (TME) - reduces local recurrence.<ref name=pmid8665198>{{Cite journal | last1 = Arbman | first1 = G. | last2 = Nilsson | first2 = E. | last3 = Hallböök | first3 = O. | last4 = Sjödahl | first4 = R. | title = Local recurrence following total mesorectal excision for rectal cancer. | journal = Br J Surg | volume = 83 | issue = 3 | pages = 375-9 | month = Mar | year = 1996 | doi = | PMID = 8665198 }}</ref> | #* Specimens have should have intact mesorectum - ''[[total mesorectal excision]]'' (TME) - reduces local recurrence.<ref name=pmid8665198>{{Cite journal | last1 = Arbman | first1 = G. | last2 = Nilsson | first2 = E. | last3 = Hallböök | first3 = O. | last4 = Sjödahl | first4 = R. | title = Local recurrence following total mesorectal excision for rectal cancer. | journal = Br J Surg | volume = 83 | issue = 3 | pages = 375-9 | month = Mar | year = 1996 | doi = | PMID = 8665198 }}</ref> | ||
# Abdominoperineal resection (APR) - anus + rectum - results in a permanent [[stoma]] (for distal rectal malignancies). | # [[Abdominoperineal resection]] (APR) - anus + rectum - results in a permanent [[stoma]] (for distal rectal malignancies). | ||
# [[Stoma]] - these are often done emergently and then get cut-out after the patient's condition has settled. | # [[Stoma]] - these are often done emergently and then get cut-out after the patient's condition has settled. | ||
#[[Doughnuts]] (also ''donuts'') from an end-to-end anastomosis stapler. | #[[Doughnuts]] (also ''donuts'') from an end-to-end anastomosis stapler. | ||
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**Rectum starts/sigmoid ends @ place where serosa ends on the posterior aspect of the bowel. | **Rectum starts/sigmoid ends @ place where serosa ends on the posterior aspect of the bowel. | ||
***The proximal, anterior aspect of the rectum has serosa, i.e. it is not painted. | ***The proximal, anterior aspect of the rectum has serosa, i.e. it is not painted. | ||
Note: | |||
*There are several definitions for the rectum.<ref name=pmid24130630>{{Cite journal | last1 = Kenig | first1 = J. | last2 = Richter | first2 = P. | title = Definition of the rectum and level of the peritoneal reflection - still a matter of debate? | journal = Wideochir Inne Tech Maloinwazyjne | volume = 8 | issue = 3 | pages = 183-6 | month = Sep | year = 2013 | doi = 10.5114/wiitm.2011.34205 | PMID = 24130630 }}</ref> | |||
**In a survey of surgeons: | |||
**67% defined it by an anatomical landmark | |||
***35% of all respondants considered the peritoneal reflection the proximal boundary of the rectum. | |||
**30% defined the proximal boundary as a distance from the anal verge. | |||
=Common non-neoplastic disease= | =Common non-neoplastic disease= | ||