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The '''colon''' smell like poo... 'cause that's where poo comes from.  This article also covers the '''rectum''' and '''cecum''' as both have a similar mucosa.   
[[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.   


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]]'' is dealt with in a separate article.
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.
#*Often accompany lower anterior resections.


===Images===
===Images===
Line 69: Line 106:
===Images===
===Images===
<gallery>
<gallery>
Image: Rectum - lateral view.jpg | Aigmoid and rectum. APR specimen. (WC)
Image: Rectum - lateral view.jpg | Sigmoid and rectum. APR specimen. (WC)
</gallery>
</gallery>


Line 79: Line 116:


==Standard method==
==Standard method==
*Bowel is prep'ed by opening it along the antimesenteric side.
*Bowel is prep'ed by [[opening]] it along the antimesenteric side.
*Dimensions - length, circumference at both [[margins]].
*Dimensions - length, circumference at both [[margins]].
*Radial margin/circumferential margin - should be painted.
*Radial margin/circumferential margin - should be painted.
**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=
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*[[AKA]] ''colonic ischemia''.
*[[AKA]] ''colonic ischemia''.
*[[AKA]] ''ischemia of the colon''.
*[[AKA]] ''ischemia of the colon''.
===General===
{{Main|Ischemic colitis}}
*May occur together with ''[[ischemic enteritis]]'', in which case it is known as ''ischemic enterocolitis''.
 
Etiology - anything that leads to vascular occlusion:
*[[Atherosclerosis]].
*[[Vasculitis]].
*Embolization, e.g. thrombotic, foreign body.
 
Possible associated pathology:
*[[Necrotizing enteritis]] - necrosis of the small bowel only.
*[[Necrotizing enterocolitis]] - necrosis of the small and large bowel.
 
Closely related:
*[[Radiation colitis]].
*[[Infectious colitis]].
 
Note:
*Ischemia = compromised blood supply.
 
===Gross===
Features - location:<ref name=Ref_PBoD852>{{Ref PBoD|852}}</ref>
*Luminal part (mucosa & submucosa) affected - edema.
*Splenic flexture of colon commonly affected (vascular watershed).
 
Note:
*May have pseudomembranes (classically assoc. with ''C. difficile'' colitis), i.e. mimics an infectious process.
*DDx for pseudomembranes:<ref name=Ref_PBoD837-8>{{Ref PBoD|837-8}}</ref>
**[[C. difficile]] induced pseudomembranous colitis.
**Ischemic colitis.
**Volvulus.
**Necrotizing infections.
**... anything that causes severe mucosal injury.
*Radiologic correlate = bowel wall thickening.
 
===Microscopic===
Features:
*Withering crypts - '''important'''.
**Colonic epithelium has decreased cytoplasm - NC ratio increased.
**Usually with decreased goblet cells.
*Crypt loss/drop-out.
**Less intestinal crypts present.
*Lamina propria hyalinization.
**Dense pink material replaces loose connective tissue.
*Submucosa hyalinization.
*+/-Pseudomembranes (microscopic):<ref name=Ref_PBoD837-8>{{Ref PBoD|837-8}}</ref>
**Loss of surface epithelium.
**[[PMN]]s in lamina propria.
**+/-Capillary fibrin thrombi.
 
Note:
*Pseudomembranes arise from the crypts - considered ''acute''.
 
DDx:
*[[Inflammatory bowel disease]].
*[[Radiation colitis]].
*Toxins/drugs.
**Rosuvastatin.<ref name=pmid22744258>{{Cite journal  | last1 = Tan | first1 = J. | last2 = Pretorius | first2 = CF. | last3 = Flanagan | first3 = PV. | last4 = Pais | first4 = A. | title = Adverse drug reaction: rosuvastatin as a cause for ischaemic colitis in a 64-year-old woman. | journal = BMJ Case Rep | volume = 2012 | issue =  | pages =  | month =  | year = 2012 | doi = 10.1136/bcr.11.2011.5270 | PMID = 22744258 }}</ref>
**[[Cocaine]].<ref name=pmid21237534>{{Cite journal  | last1 = Fabra | first1 = I. | last2 = Roig | first2 = JV. | last3 = Sancho | first3 = C. | last4 = Mir-Labrador | first4 = J. | last5 = Sempere | first5 = J. | last6 = García-Ferrer | first6 = L. | title = [Cocaine-induced ischemic colitis in a high-risk patient treated conservatively]. | journal = Gastroenterol Hepatol | volume = 34 | issue = 1 | pages = 20-3 | month = Jan | year = 2011 | doi = 10.1016/j.gastrohep.2010.10.005 | PMID = 21237534 }}</ref>
**[[NSAID]] overdose.<ref name=pmid11736840>{{Cite journal  | last1 = Appu | first1 = S. | last2 = Thompson | first2 = G. | title = Gangrenous ischaemic colitis following non-steroidal anti-inflammatory drug overdose. | journal = ANZ J Surg | volume = 71 | issue = 11 | pages = 694-5 | month = Nov | year = 2001 | doi =  | PMID = 11736840 }}</ref>
*[[Infectious colitis]].
 
====Images====
<gallery>
Image:Ischemic_colitis_-_low_mag.jpg | Ischemic colitis - low mag. (WC/Nephron)
Image:Ischemic_colitis_-_high_mag.jpg | Ischemic colitis - high mag. (WC/Nephron)
Image:Ischemic_colitis_-_very_high_mag.jpg | Ischemic colitis - very high mag. (WC/Nephron)
Image:Colonic_pseudomembranes_low_mag.jpg | Colonic pseudomembranes - low mag. (WC/Nephron)
Image:Colonic_pseudomembranes_intermed_mag.jpg | Colonic pseudomembranes - intermed. mag. (WC/Nephron)
</gallery>
www:
*[http://www.flickr.com/photos/euthman/3385570758/ Ischemic colitis (flickr.com/euthman)].
*[http://radiology.uchc.edu/eAtlas/GI/1019.htm Ischemic colitis (uchc.edu)].
 
===Sign out===
====Biopsy====
<pre>
TRANSVERSE COLON, BIOPSY:
- SEVERE ACTIVE COLITIS WITH ATTENUATED EPITHELIAL CYTOPLASM AND ULCERATION.
- CELLULAR DEBRIS.
- NEGATIVE FOR DYSPLASIA AND NEGATIVE FOR MALIGNANCY.
 
COMMENT:
The attenuated cytoplasm is compatible with ischemia; however, it is not
accompanied with other suggestive findings (crypt drop out, lamina propria
fibrosis, pseudomembranes).  The crypt architecture is test tube-like.
 
The differential diagnosis includes: ischemia, drug reaction, infectious
etiologies and, less likely, inflammatory bowel disease. Clinical
correlation is required.
</pre>
 
<pre>
COLON, SPLENIC FLEXURE, BIOPSY:
- PATCHY MODERATE ACTIVE COLITIS WITH ATTENUATED EPITHELIAL CYTOPLASM,
  FOCALLY DECREASED GOBLET CELLS AND ULCERATION.
- NEGATIVE FOR DYSPLASIA AND NEGATIVE FOR MALIGNANCY.
 
COMMENT:
The findings are consistent with ischemia; however, they are not diagnostic.
 
The differential diagnosis includes: ischemia, drug reaction, infectious
etiologies and, less likely, inflammatory bowel disease. Clinical
correlation is required.
</pre>
 
====Short version====
<pre>
LEFT COLON AND SIGMOID COLON, RESECTION:
- PSEUDOMEMBRANOUS COLITIS, SEE COMMENT.
- ONE LYMPH NODE NEGATIVE FOR MALIGNANCY ( 0 POSITIVE / 1 ).
- NEGATIVE FOR DYSPLASIA AND NEGATIVE FOR MALIGNANCY.
 
COMMENT:
Pseudomembrane formation is a non-specific finding.  It is consistent with ischemia;
however, it may be seen in other contexts, including infection. Clinical correlation is
required.
</pre>
 
====Long version====
<pre>
RECTOSIGMOID, RESECTION:
- BOWEL WALL ISCHEMIA WITH PERFORATION, SEROSITIS, MICROABSCESS FORMATION AND FOCAL
POORLY FORMED PSEUDOMEMBRANES.
- NEGATIVE FOR MALIGNANCY.
- PLEASE SEE COMMENT.
 
COMMENT:
There is no evidence of inflammatory bowel disease:
The unaffected mucosa does not have obvious architectural distortion. No granulomas are
identified. The inflammation is largely associated with necrosis/ischemic changes
and favoured to be reactive.
 
The poorly formed pseudomembranes are associated with mural ischemic changes; they do not
specifically suggest an infection in this context.
 
The blood vessels do not show a vasculitis, or significant atherosclerosis.  Thrombi are
seen on several sections and found predominantly in the (smaller) veins.
 
Considerations are thrombosis, thromboembolism, mechanical vascular compromise, and
infectious etiologies.  A vascular compromise is favoured as the underlying cause.
 
Clinical and radiologic correlation is suggested.
</pre>
 
====Another long version====
<pre>
SIGMOID COLON, RESECTION:
- BOWEL WALL ISCHEMIA WITH PERFORATION, SEROSITIS, AND FOCAL POORLY FORMED
PSEUDOMEMBRANES.
- MILD ATHEROSCLEROSIS.
- DIVERTICULAR DISEASE.
- TWO LYMPH NODES NEGATIVE FOR MALIGNANCY ( 0 POSITIVE / 2 ).
- PLEASE SEE COMMENT.
 
COMMENT:
The sections show the changes of acute and chronic ischemic colitis (submucosal fibrosis,
lamina propria hyalinization, focal crypt drop-out, decreased goblet cells, pigmented
macrophages in the lamina propria, intraepithelial neutrophils).
 
No granulomas are identified. The inflammation is largely associated with
the necrosis/ischemic changes and favoured to be reactive.
 
The poorly formed pseudomembranes are associated with mural ischemic changes; they do not
specifically suggest an infectious etiology in this context.
 
The blood vessels do not show a vasculitis. However, focal neutrophilic perivascular
inflammation is seen; this is probably a reactive process. No vascular thrombi are
identified.
 
The findings are compatible with perforation secondary to a foreign body in the setting of
chronic ischemia.
</pre>
 
====Micro====
=====Negative for ischemic colitis=====
The sections show colorectal mucosa with preservation of the crypt density and
epithelium with a normal nuclear-to-cytoplasm ratio. There is no apparent lamina propria
hyalinization.  The muscularis mucosa is prominent.  Focally, lymphoid aggregates are
present.
 
No cryptitis is present.  Neutrophils are not apparent in the lamina propria. No erosions
are identified.
 
The epithelium matures appropriately from the crypt base to the surface.


==Diverticular disease==
==Diverticular disease==
:''Diverticulitis'' redirect here.
{{Main|Diverticular disease}}
*[[AKA]] ''diverticulosis''.
===General===
*Very common.
 
Complications:
*Diverticulitis.
*Diverticular-associated colitis<ref>{{Cite journal  | last1 = Mulhall | first1 = AM. | last2 = Mahid | first2 = SS. | last3 = Petras | first3 = RE. | last4 = Galandiuk | first4 = S. | title = Diverticular disease associated with inflammatory bowel disease-like colitis: a systematic review. | journal = Dis Colon Rectum | volume = 52 | issue = 6 | pages = 1072-9 | month = Jun | year = 2009 | doi = 10.1007/DCR.0b013e31819ef79a | PMID = 19581849 }}</ref> - rare.
**Rectal biopsy to differentiate from [[ulcerative colitis]].
 
===Gross===
*Corrugated - like cardboard.
*Wall thickening (reactive).<ref name=pmid21359889>{{Cite journal  | last1 = Nicholson | first1 = BD. | last2 = Hyland | first2 = R. | last3 = Rembacken | first3 = BJ. | last4 = Denyer | first4 = M. | last5 = Hull | first5 = MA. | last6 = Tolan | first6 = DJ. | title = Colonoscopy for colonic wall thickening at computed tomography: a worthwhile pursuit? | journal = Surg Endosc | volume = 25 | issue = 8 | pages = 2586-91 | month = Aug | year = 2011 | doi = 10.1007/s00464-011-1591-7 | PMID = 21359889 }}</ref>
 
====Endoscopic image====
<gallery>Image:Diverticulosis_2.jpg | Diverticular disease. (WC/Samir)</gallery>
 
====Grossing notes====
*[[pp:Diverticular disease]].
 
===Microscopic===
Features:
*Mucosa/submucosa invagination into the musuclaris propria (MP).
**At the site the blood vessels supplying the mucosa and submucosa penetrate the MP.<ref name=pmid18936652>{{Cite journal  | last1 = West | first1 = AB. | title = The pathology of diverticulitis. | journal = J Clin Gastroenterol | volume = 42 | issue = 10 | pages = 1137-8 | month =  | year =  | doi = 10.1097/MCG.0b013e3181862a9f | PMID = 18936652 }}</ref>
 
Image:
*[http://histology-group28.wikispaces.com/file/view/divertic.jpg/60992930/divertic.jpg DD (wikispaces.com)].<ref>URL: [http://histology-group28.wikispaces.com/DigestiveSystemProject http://histology-group28.wikispaces.com/DigestiveSystemProject]. Accessed on: 23 August 2011.</ref>
 
===Sign out===
<pre>
RECTO-SIGMOID, LARGE BOWEL RESECTION:
- PERFORATED DIVERTICULITIS WITH SEROSITIS AND ABSCESS FORMATION.
- SUBMUCOSAL FIBROSIS.
- ONE LYMPH NODE NEGATIVE FOR MALIGNANCY ( 0 POSITIVE / 1 ).
- NEGATIVE FOR MALIGNANCY.
</pre>
 
<pre>
SIGMOID COLON, SIGMOIDECTOMY:
- DIVERTICULAR DISEASE WITHOUT DIVERTICULITIS.
- NEGATIVE FOR MALIGNANCY.
</pre>


==Pseudomembranous colitis==
==Pseudomembranous colitis==
===General===
{{Main|Pseudomembranous colitis}}
*''Pseudomembranous colitis'' is a histomorphologic description which has a [[DDx]]. In other words, it can be caused by a number of things.
 
DDx of pseudomembranous colitis:<ref name=Ref_PBoD837-8>{{Ref PBoD|837-8}}</ref>
*[[C. difficile]].
**Known as ''C. difficile colitis''.
*[[Ischemic colitis]].
**Volvulus.
*Other infections.
 
Etiology:
*Anything that causes a severe mucosal injury.
 
===Gross===
Features:<ref>URL: [http://radiology.uchc.edu/eAtlas/GI/1749.htm http://radiology.uchc.edu/eAtlas/GI/1749.htm]. Accessed on: 22 May 2012.</ref>
*Pseudomembranes:
**Pale yellow (or white) irregular, raised mucosal lesions.
**Early lesions: typical <10 mm.
*Interlesional mucosa often near normal grossly.
 
Images:
*[http://en.wikipedia.org/wiki/File:PMC_1.jpg Pseudomembranous colitis - endoscopic image (WP/Samir)].
<gallery>
Image:Pseudomembranous_colitis.JPG | Pseudomembranous colitis (WC/Nephron)
</gallery>
===Microscopic===
Features:<ref name=Ref_PBoD837-8>{{Ref PBoD|837-8}}</ref>
*Heaped necrotic surface epithelium.
**Described as "volanco lesions" - this is what is seen endoscopically.
*[[PMN]]s in lamina propria.
*+/-Capillary fibrin thrombi.
 
Notes:
*Pseudomembranes arise from the crypts.
*Rarely have (benign) [[signet ring cell]]-like cells.<ref name=pmid12684766>{{Cite journal  | last1 = Abdulkader | first1 = I. | last2 = Cameselle-Teijeiro | first2 = J. | last3 = Forteza | first3 = J. | title = Signet-ring cells associated with pseudomembranous colitis. | journal = Virchows Arch | volume = 442 | issue = 4 | pages = 412-4 | month = Apr | year = 2003 | doi = 10.1007/s00428-003-0779-1 | PMID = 12684766 }}</ref>
 
====Images====
<gallery>
Image:Colonic_pseudomembranes_low_mag.jpg | Pseudomembranes - low mag. (WC/Nephron)
Image:Colonic_pseudomembranes_intermed_mag.jpg | Pseudomembranes - intermed. mag. (WC/Nephron)
</gallery>
www:
*[http://path.upmc.edu/cases/case153.html Pseudomembranous colitis (upmc.edu)].


==Volvulus==
==Volvulus==
===General===
{{Main|Volvulus}}
*Uncommonly comes to pathology.
*It is essentially a radiologic diagnosis.
*In the context of [[autopsy]], it is a gross diagnosis.
 
===Gross===
*Intestine folded over itself - typically leads to ischemia.
 
Images:
*[http://library.med.utah.edu/WebPath/GIHTML/GI032.html Cecal volvulus (utah.edu)].
*[http://pathsrvr.rockford.uic.edu/inet/GI/Photo%202%20-%20Volvulus%20of%20small%20intestine_%20gross.gif Volvulus (uic.edu)].<ref>URL: [http://pathsrvr.rockford.uic.edu/inet/GI/GI%20Station%201.htm http://pathsrvr.rockford.uic.edu/inet/GI/GI%20Station%201.htm]. Accessed on: 9 April 2012.</ref>
 
===Microscopic===
Features:
*+/-Ischemic changes and/or [[necrosis]].
 
DDx - essentially anything that causes ischemia:
*Embolus.
*Thrombosis.
*[[Vasculitis]].
 
===Sign out===
<pre>
RECTOSIGMOID, RESECTION:
- MURAL ISCHEMIA WITH PERFORATION, SEROSITIS, MICROABSCESS FORMATION AND POORLY FORMED PSEUDOMEMBRANES.
- SUBMUCOSAL FIBROSIS.
- NEGATIVE FOR MALIGNANCY.
 
COMMENT:
The findings are consistent with volvulus and the submucosal fibrosis suggests this may have been recurrent.
</pre>


=Inflammatory diseases=
=Inflammatory diseases=
Line 421: Line 169:
*Basal, i.e. crypt base, plasmacytosis with severe chronic inflammation,
*Basal, i.e. crypt base, plasmacytosis with severe chronic inflammation,
*Crypt architectural abnormalities, and
*Crypt architectural abnormalities, and
*Distal Paneth cell metaplasia.
*Distal [[Paneth cell]] metaplasia.
**Paneth cells should ''not'' be in the left colon<ref name=pmid11851832>{{cite journal |author=Tanaka M, Saito H, Kusumi T, ''et al'' |title=Spatial distribution and histogenesis of colorectal Paneth cell metaplasia in idiopathic inflammatory bowel disease |journal=J. Gastroenterol. Hepatol. |volume=16 |issue=12 |pages=1353–9 |year=2001 |month=December |pmid=11851832 |doi= |url=http://www3.interscience.wiley.com/resolve/openurl?genre=article&sid=nlm:pubmed&issn=0815-9319&date=2001&volume=16&issue=12&spage=1353}}</ref> - if you see 'em think of IBD and other long-standing injurious processes.
**Paneth cells should ''not'' be in the left colon<ref name=pmid11851832>{{cite journal |author=Tanaka M, Saito H, Kusumi T, ''et al'' |title=Spatial distribution and histogenesis of colorectal Paneth cell metaplasia in idiopathic inflammatory bowel disease |journal=J. Gastroenterol. Hepatol. |volume=16 |issue=12 |pages=1353–9 |year=2001 |month=December |pmid=11851832 |doi= |url=http://www3.interscience.wiley.com/resolve/openurl?genre=article&sid=nlm:pubmed&issn=0815-9319&date=2001&volume=16&issue=12&spage=1353}}</ref> - if you see 'em think of IBD and other long-standing injurious processes.
**Some claim that (friendly right colonic) paneth cells and paneth cell metaplasia look quite different and can be distinguished.<ref name=pmid12655793>{{cite journal |author=Rubio CA, Nesi G |title=A simple method to demonstrate normal and metaplastic Paneth cells in tissue sections |journal=In Vivo |volume=17 |issue=1 |pages=67–71 |year=2003 |pmid=12655793 |doi= |url=}}</ref>
**Some claim that (friendly right colonic) paneth cells and paneth cell metaplasia look quite different and can be distinguished.<ref name=pmid12655793>{{cite journal |author=Rubio CA, Nesi G |title=A simple method to demonstrate normal and metaplastic Paneth cells in tissue sections |journal=In Vivo |volume=17 |issue=1 |pages=67–71 |year=2003 |pmid=12655793 |doi= |url=}}</ref>


==Microscopic colitis==
==Microscopic colitis==
:''Microscopic colitis'' may refer to a microscopic manifestation of an unspecified disease process that can be apparent macroscopically. This section deals with a pair of diseases (''lymphocytic colitis'' and ''collagenous colitis'') that are considered to only have microscopic manifestations and characteristic clinical presentation.
:''Microscopic colitis'' may refer to a microscopic manifestation of an unspecified disease process that can be apparent macroscopically. This section links to a pair of diseases (''lymphocytic colitis'' and ''collagenous colitis'') that are considered to only have microscopic manifestations and characteristic clinical presentation.
===General===
{{Main|Lymphocytic colitis}}
Presentation:
{{Main|Collagenous colitis}}
*Chronic diarrhea, non-bloody.<ref name=medscape180664>URL: [http://emedicine.medscape.com/article/180664-overview http://emedicine.medscape.com/article/180664-overview]. Accessed on: 31 May 2010.</ref>
 
Notes:
*Clinical DDx includes [[irritable bowel syndrome]] - which has no or subtle histopathologic changes.
 
====Classification====
*Lymphocytic colitis (LC).
*Collagenous colitis (CC).
 
Note:
*Some believe that LC and CC are different time points in the same process-- but this is unproven.<ref name=medscape180664/>
 
====Epidemiology====
*Age: a disease of adults - usually 50s.
*Sex:
**LC males ~= females,<ref name=medscape180664/>
**CC females:males = 20:1.<ref name=medscape180664/>
*Drugs are associated with LC and CC.
**NSAIDs - posulated association/weak association,
**SSRIs (used primarily for depression) - moderate association, dependent on specific drug.
*Associated with autoimmune disorders - [[celiac disease]], [[diabetes mellitus]], [[thyroid]] disorders and [[arthritis]].<ref name=pmid19109861>{{cite journal |author=Tysk C, Bohr J, Nyhlin N, Wickbom A, Eriksson S |title=Diagnosis and management of microscopic colitis |journal=World J. Gastroenterol. |volume=14 |issue=48 |pages=7280-8 |year=2008 |month=December |pmid=19109861 |doi= |url=http://www.wjgnet.com/1007-9327/14/7280.asp}}</ref>
*No increased risk of colorectal carcinoma.<ref name=pmid19109861/>
 
====Treatment====
*Sometimes just follow-up.
*Steroids - budesonide -- short-term treatment.<ref name=pmid19109861/>
 
===Gross===
*As the name suggests, they are microscopic, i.e. endoscopic examination is normal.
 
===Microscopic===
====Lymphocytic colitis====
Features:
*Lots of intraepithelial lymphocytes (>=20/100 lymphocytes/surface epithelial cells<ref name=pmid19109861>{{cite journal |author=Tysk C, Bohr J, Nyhlin N, Wickbom A, Eriksson S |title=Diagnosis and management of microscopic colitis |journal=World J. Gastroenterol. |volume=14 |issue=48 |pages=7280-8 |year=2008 |month=December |pmid=19109861 | PMC = 2778111 |doi= |url=http://www.wjgnet.com/1007-9327/14/7280.asp}}</ref>) and
*Lymphocytes in the lamina propria.
 
Significant negatives:<ref name=hopkins_cc_lc>[http://hopkins-gi.nts.jhu.edu/pages/latin/templates/index.cfm?pg=disease1&disease=29&organ=6&lang_id=1 http://hopkins-gi.nts.jhu.edu/pages/latin/templates/index.cfm?pg=disease1&disease=29&organ=6&lang_id=1]</ref>
*No neutrophils.
*No crypt distortion.
 
DDx:
*[[Infectious colitis]] - neutrophils present... not lymphocytes.
*[[Collagenous colitis]] - has a band of collagen below the epithelium.
 
Image:
*[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2778111/figure/F2/ LC (nih.gov)].<ref name=pmid19109861/>
 
====Collagenous colitis====
Features:
*Intraepithelial lymphocytes, and
*lymphocytes in the lamina propria.
*Collagenous material in the lamina propria (pink on H&E) -- '''key feature'''.
**Can be demonstrated with a trichrome stain -- collagen = green on trichrome.
**Subepithelial collagen needs to be >= 10 micrometres thick for diagnosis.<ref name=pmid19109861/>
***8 micrometres is the diameter of a RBC.
***The normal thickness of the subepithelial collagen is 3 micrometres.<ref name=pmid19109861/>
***Transverse colon usually thickest - in one series ~47 micrometres on average.<ref name=pmid10208468>{{Cite journal  | last1 = Offner | first1 = FA. | last2 = Jao | first2 = RV. | last3 = Lewin | first3 = KJ. | last4 = Havelec | first4 = L. | last5 = Weinstein | first5 = WM. | title = Collagenous colitis: a study of the distribution of morphological abnormalities and their histological detection. | journal = Hum Pathol | volume = 30 | issue = 4 | pages = 451-7 | month = Apr | year = 1999 | doi =  | PMID = 10208468 }}</ref>
****Thickening is usually patchy.<ref name=pmid1740280/>
**Thickening "follows the crypts from the surface" - useful for differentiating from tangential sections of the basement membrane.<ref name=bell>Bell, D. 4 Mar 2009.</ref>
**Collagen may envelope capillaries - useful to discern from basement membrane.<ref name=bell>Bell, D. 4 Mar 2009.</ref>
 
Notes:
*CC is typically more prominent in the proximal colon - may reflect concentration gradient of offending causitive agents.<ref name=pmid19109861/>
*Significant negative findings:<ref name=hopkins_cc_lc/>
**No [[PMN]]s.
**No crypt distortion.
*Thickened collagen band uncommon in rectum.<ref name=pmid1740280>{{Cite journal  | last1 = Tanaka | first1 = M. | last2 = Mazzoleni | first2 = G. | last3 = Riddell | first3 = RH. | title = Distribution of collagenous colitis: utility of flexible sigmoidoscopy. | journal = Gut | volume = 33 | issue = 1 | pages = 65-70 | month = Jan | year = 1992 | doi =  | PMID = 1740280 }}</ref>
 
====Images====
<gallery>
Image:Collagenous_colitis_-_intermed_mag.jpg | CC - intermed mag. (WC/Nephron)
Image:Collagenous_colitis_-_high_mag.jpg | CC - high mag. (WC/Nephron)
</gallery>
 
===Sign out===
<pre>
TRANSVERSE COLON, BIOPSY:
- COLLAGENOUS COLITIS.
</pre>
 
<pre>
ASCENDING COLON, BIOPSY:
- LYMPHOCYTIC COLITIS.
</pre>
 
====Micro====
=====Lymphocytic colitis=====
The sections show colonic mucosa with abundant intraepithelial lymphocytes (>20 lymphocytes/100 surface epithelial cells). The glandular architecture is within normal limits. No thickened collagen band is apparent below the epithelium.
 
There are no granulomas. No neutrophilic cryptitis is apparent. The epithelium matures
appropriately to the surface.
 
=====Collagenous colitis=====
The sections show colonic mucosa with abundant intraepithelial lymphocytes (>20 lymphocytes/100 surface epithelial cells). A prominent collagen band is apparent below the epithelium (>10 micrometres thick). The glandular architecture is within normal limits.
 
There are no granulomas. No neutrophilic cryptitis is apparent. The epithelium matures
appropriately to the surface.


==Diversion colitis==
==Diversion colitis==
:''Diversion proctitis'' redirect here.
{{Main|Diversion colitis}}
===General===
*Segment of de-functioned bowel due to surgical diversion, i.e. stoma (ileostomy or [[colostomy]]).
*[[Diagnosis]] dependent on history - '''key point'''.
 
===Gross===
Features:<ref name=pmid9934577/>
*Ulceration - classic.
*Surgical changes, e.g. fibrotic-appearing thickened wall.
**May not be apparent.
 
===Microscopic===
Features:<ref name=pmid9934577>{{Cite journal  | last1 = Edwards | first1 = CM. | last2 = George | first2 = B. | last3 = Warren | first3 = B. | title = Diversion colitis--new light through old windows. | journal = Histopathology | volume = 34 | issue = 1 | pages = 1-5 | month = Jan | year = 1999 | doi =  | PMID = 9934577 }}</ref>
*Follicular lymphoid hyperplasia - '''key feature'''.<ref name=pmid1916687>{{Cite journal  | last1 = Yeong | first1 = ML. | last2 = Bethwaite | first2 = PB. | last3 = Prasad | first3 = J. | last4 = Isbister | first4 = WH. | title = Lymphoid follicular hyperplasia--a distinctive feature of diversion colitis. | journal = Histopathology | volume = 19 | issue = 1 | pages = 55-61 | month = Jul | year = 1991 | doi =  | PMID = 1916687 }}</ref>
**Abundant lymphoid nodules.
*[[Plasma cell]]s and lymphocytes.
*+/-Changes of an active colitis - uncommon:<ref name=pmid2318485>{{Cite journal  | last1 = Ma | first1 = CK. | last2 = Gottlieb | first2 = C. | last3 = Haas | first3 = PA. | title = Diversion colitis: a clinicopathologic study of 21 cases. | journal = Hum Pathol | volume = 21 | issue = 4 | pages = 429-36 | month = Apr | year = 1990 | doi =  | PMID = 2318485 }}</ref>
**Cryptitis.
**Crypt abscesses.
 
Notes:
*May show IBD-like changes.<ref name=pmid16405661>{{Cite journal  | last1 = Yantiss | first1 = RK. | last2 = Odze | first2 = RD. | title = Diagnostic difficulties in inflammatory bowel disease pathology. | journal = Histopathology | volume = 48 | issue = 2 | pages = 116-32 | month = Jan | year = 2006 | doi = 10.1111/j.1365-2559.2005.02248.x | PMID = 16405661 }}</ref>
**IBD should '''not''' be diagnosed on a diverted segment of bowel.
 
DDx:<ref name=pmid20011361>{{Cite journal  | last1 = Thorsen | first1 = AJ. | title = Noninfectious colitides: collagenous colitis, lymphocytic colitis, diversion colitis, and chemically induced colitis. | journal = Clin Colon Rectal Surg | volume = 20 | issue = 1 | pages = 47-57 | month = Feb | year = 2007 | doi = 10.1055/s-2007-970200 | PMID = 20011361 | PMC = 2780148| url=http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2780148/ }}</ref>
*[[Inflammatory bowel disease]] - no stoma.
*[[Ischemic colitis]].
*[[Infectious colitis]].
**[[Pseudomembranous colitis]].
 
====Images====
<gallery>
Image:Diversion_proctitis_-_low_mag.jpg | Diversion proctitis - low mag. (WC/Nephron)
Image:Diversion_proctitis_-_high_mag.jpg | Diversion proctitis - high mag. (WC/Nephron)
</gallery>
===Sign out===
<pre>
SIGMOID COLON, BIOPSIES:
- MILD ACTIVE COLITIS WITH LAMINA PROPRIA FIBROSIS, SEE COMMENT.
- NEGATIVE FOR DYSPLASIA.
 
COMMENT:
No granulomas are identified.  Follicular lymphoid hyperplasia is not identified;
however, there is no definite submucosa present.
 
Diverted segments of bowel can have inflammatory bowel disease-like changes.
 
In the context of a diverted segment of bowel, the findings are compatible with
a diversion colitis.
</pre>


==Eosinophilic colitis==
==Eosinophilic colitis==
===General===
*Abbreviated ''EC''.
*Rare.
{{Main|Eosinophilic colitis}}
*May be a component of ''[[eosinophilic gastroenteritis]]''.<ref name=pmid22012125/>
 
Clinical features:<ref name=pmid22012125/>
*Abdominal pain
*Diarrhea +/-blood.
*+/-Weight loss.
 
===Gross===
Features - endoscopic:<ref name=pmid22012125>{{Cite journal  | last1 = Alfadda | first1 = AA. | last2 = Storr | first2 = MA. | last3 = Shaffer | first3 = EA. | title = Eosinophilic colitis: an update on pathophysiology and treatment. | journal = Br Med Bull | volume = 100 | issue =  | pages = 59-72 | month =  | year = 2011 | doi = 10.1093/bmb/ldr045 | PMID = 22012125 | PMC = 3165205 }}</ref>
*Edema.
*Granular appearance.
 
===Microscopic===
Features:<ref name=pmid22012125/>
*Abundant eosinophils - no agreed upon number.
**"Most use 20/[[HPF]]" <ref name=pmid19554649>{{Cite journal  | last1 = Okpara | first1 = N. | last2 = Aswad | first2 = B. | last3 = Baffy | first3 = G. | title = Eosinophilic colitis. | journal = World J Gastroenterol | volume = 15 | issue = 24 | pages = 2975-9 |  month = Jun | year = 2009 | doi =  | PMID = 19554649 | PMC = 2702104 }}</ref> - a definition that suffers from [[HPFitis]].
***There is variation along the large bowel - normal in rectum <10/HPF, normal in cecum <30/HPF (???).<ref name=pmid19554649/>
 
DDx:<ref name=pmid22012125/>
*[[Inflammatory bowel disease]]:
**[[Crohn's disease]].
**[[Ulcerative colitis]].
*Infection:
**[[Pinworm]].
**[[Strongyloidiasis]].
*Autoimmune disease:
**[[Scleroderma]].
**[[Churg-Strauss syndrome]].
**[[Celiac disease]].
*[[Drug reaction]]s.
 
Image:
*[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2702104/figure/F1/ EC (nih.gov)].<ref name=pmid19554649>{{Cite journal  | last1 = Okpara | first1 = N. | last2 = Aswad | first2 = B. | last3 = Baffy | first3 = G. | title = Eosinophilic colitis. | journal = World J Gastroenterol | volume = 15 | issue = 24 | pages = 2975-9 | month = Jun | year = 2009 | doi =  | PMID = 19554649 | PMC = 2702104 }}</ref>
 
===Sign out===
<pre>
DESCENDING COLON, BIOPSY:
- COLONIC MUCOSA WITH MILD EOSINOPHILIA, SEE COMMENT.
- NEGATIVE FOR DYSPLASIA.
 
COMMENT:
Focally, there are up to 40 eosinophils / 0.2376 mm*mm (approx. field area at 400X). This
is a non-specific finding. No eosinophilic crypt abscesses are seen. No (neutrophilic)
cryptitis is present. Clinical correlation is suggested.
</pre>
 
<pre>
DESCENDING COLON, BIOPSY:
- COLONIC MUCOSA WITH MILD EOSINOPHILIA, SEE COMMENT.
- NEGATIVE FOR ACTIVE COLITIS.
- NEGATIVE FOR DYSPLASIA.
 
COMMENT:
There are up to 40 eosinophils / 0.2376 mm*mm (field area at 400X). This is a
non-specific finding.  The differential diagnosis includes inflammatory bowel
disease, infection (especially helminths), a drug reaction, and autoimmune
disorders (e.g. Churg-Strauss syndrome, celiac disease, scleroderma). Clinical
correlation is required.
</pre>


=Infectious=
=Infectious=
Line 696: Line 239:
{{Main|CMV}}
{{Main|CMV}}
*Abbreviated ''CMV colitis''.
*Abbreviated ''CMV colitis''.
===General===
{{Main|Cytomegalovirus colitis}}
*Uncommon.
*Immunosuppressed population at risk, e.g. transplant recipients, individuals with [[HIV]].
 
===Microscopic===
Features:
*Enlarged nucleus - classically in endothelial cells.
 
DDx:
*[[Infectious colitis]] without a distinctive morphology.
*CMV colitis superimposed on [[inflammatory bowel disease]].
 
====Images====
<gallery>
Image:CMV_colitis_-_intermed_mag.jpg | CMV colitis - intermed. mag. (WC/Nephron)
Image:CMV_colitis_-_high_mag_-_cropped.jpg | CMV colitis - high mag. (WC/Nephron)
</gallery>
 
===IHC===
*CMV +ve.
 
Others:
*HSV-1.
*HSV-2.
*VZV.
*[[EBV]].


==Intestinal spirochetosis==
==Intestinal spirochetosis==
*[[AKA]] ''intestinal spirochetes''; more specifically ''colonic spirochetes'', ''colonic spirochetosis''.
*[[AKA]] ''intestinal spirochetes''; more specifically ''colonic spirochetes'', ''colonic spirochetosis''.
 
{{Main|Intestinal spirochetosis}}
===General===
*Caused by spirochetes<ref name=pmid14718105>{{cite journal |author=Amat Villegas I, Borobio Aguilar E, Beloqui Perez R, de Llano Varela P, Oquiñena Legaz S, Martínez-Peñuela Virseda JM |title=[Colonic spirochetes: an infrequent cause of adult diarrhea] |language=Spanish; Castilian |journal=Gastroenterol Hepatol |volume=27 |issue=1 |pages=21–3 |year=2004 |month=January |pmid=14718105 |doi= |url=}}</ref><ref name=jhasim>URL: [http://www.jhasim.com/files/articlefiles/pdf/XASIM_Master_6_5_May_Vignette.pdf http://www.jhasim.com/files/articlefiles/pdf/XASIM_Master_6_5_May_Vignette.pdf]. Accessed on: 25 April 2011.</ref> - specifically ''Brachyspira piloicoli''<ref name=pmid19141744>{{Cite journal  | last1 = Margawani | first1 = KR. | last2 = Robertson | first2 = ID. | last3 = Hampson | first3 = DJ. | title = Isolation of the anaerobic intestinal spirochaete Brachyspira pilosicoli from long-term residents and Indonesian visitors to Perth, Western Australia. | journal = J Med Microbiol | volume = 58 | issue = Pt 2 | pages = 248-52 | month = Feb | year = 2009 | doi = 10.1099/jmm.0.004770-0 | PMID = 19141744 | url = http://ukpmc.ac.uk/abstract/MED/19141744/abstract/MED/19141744?ukpmc_extredirect=http://dx.doi.org/10.1099/jmm.0.004770-0 }}</ref> (previously ''Serpulina pilosicoli''<ref>URL: [http://www.cdc.gov/ncidod/eid/vol12no05/05-1180.htm http://www.cdc.gov/ncidod/eid/vol12no05/05-1180.htm]. Accessed on: 28 June 2011.</ref>) and ''Brachyspira aalborgi''.
*Very rare cause of diarrhea, associated with male homosexual behaviour.
 
Symptoms:<ref name=jhasim>URL: [http://www.jhasim.com/files/articlefiles/pdf/XASIM_Master_6_5_May_Vignette.pdf http://www.jhasim.com/files/articlefiles/pdf/XASIM_Master_6_5_May_Vignette.pdf]. Accessed on: 25 April 2011.</ref>
*Watery diarrhea, abdominal pain, +/-blood per rectum.
 
Treatment:<ref name=pmid17914949>{{cite journal |author=Calderaro A, Bommezzadri S, Gorrini C, ''et al.'' |title=Infective colitis associated with human intestinal spirochetosis |journal=J. Gastroenterol. Hepatol. |volume=22 |issue=11 |pages=1772–9 |year=2007 |month=November |pmid=17914949 |doi=10.1111/j.1440-1746.2006.04606.x |url=}}</ref>
*Metronidazole.
 
===Microscopic===
Features:
*Hyperchromatic fuzz on luminal aspect of epithelial cells; at brush border.
 
DDx:
*Normal colon.
*[[Infectious colitis]] without a distinctive morphology.
 
====Images====
<gallery>
Image:Intestinal_spirochetosis_-_cropped_-_very_high_mag.jpg | Intestinal spirochetes - cropped - very high mag. (WC/Nephron)
Image:Intestinal_spirochetosis_-_very_high_mag.jpg | Intestinal spirochetes - very high mag. (WC/Nephron)
Image:Intestinal_spirochetosis_-_intermed_mag.jpg | Intestinal spirochetes - intermed. mag. (WC/Nephron)
</gallery>
www:
*[http://path.upmc.edu/cases/case391.html Intestinal spirochetosis & CMV colitis - several images (upmc.edu)].
===Special stains===
*Silver stains highlight 'em (e.g. Warthin-Starry stain).


==Amebiasis==
==Amebiasis==
*May also be spelling ''amoebiasis''.
*May also be spelled ''amoebiasis''.
===General===
{{Main|Amebiasis}}
*Infection with ''Entamoeba histolytica''.<ref>URL: [http://www.health.state.ny.us/diseases/communicable/amebiasis/fact_sheet.htm http://www.health.state.ny.us/diseases/communicable/amebiasis/fact_sheet.htm]. Accessed on: 17 June 2010.</ref>
*May mimic [[colon cancer]].<ref name=pmid19332922>{{Cite journal  | last1 = Fernandes | first1 = H. | last2 = D'Souza | first2 = CR. | last3 = Swethadri | first3 = GK. | last4 = Naik | first4 = CN. | title = Ameboma of the colon with amebic liver abscess mimicking metastatic colon cancer. | journal = Indian J Pathol Microbiol | volume = 52 | issue = 2 | pages = 228-30 | month =  | year =  | doi =  | PMID = 19332922 | url=http://www.ijpmonline.org/article.asp?issn=0377-4929;year=2009;volume=52;issue=2;spage=228;epage=230;aulast=Fernandes }}</ref>
 
May cause:<ref name=pmid20303955>{{Cite journal  | last1 = Mortimer | first1 = L. | last2 = Chadee | first2 = K. | title = The immunopathogenesis of Entamoeba histolytica. | journal = Exp Parasitol | volume =  | issue =  | pages =  | month = Mar | year = 2010 | doi = 10.1016/j.exppara.2010.03.005 | PMID = 20303955 }}</ref>
*Dysentery (diarrhea containing mucus and/or blood in the feces).
*Colitis.
*Liver abscess.
 
===Microscopic===
Features:
*Entamoeba histolytica are round/ovoid eosinophilic bodies ~ 40-60 micrometers in maximal dimension.
**Found in bowel lumen.
**Ingest [[RBC]]s.
 
====Image====
<gallery>
Image:Amebiasis_-_very_high_mag.jpg | Amebiasis - very high mag. (WC/Nephron)
Image:Amoebic_dysentery_in_colon_biopsy_%281%29.jpg | Amebiasis (WC)
</gallery>


==Cryptosporidiosis==
==Cryptosporidiosis==
Line 793: Line 264:
*[[AKA]] ''solitary rectal ulcer syndrome''.
*[[AKA]] ''solitary rectal ulcer syndrome''.
*''[[Mucosal prolapse syndrome]]'' may be used as a synonym; however, it encompasses other entities.<ref name=pmid22697798>{{Cite journal  | last1 = Abid | first1 = S. | last2 = Khawaja | first2 = A. | last3 = Bhimani | first3 = SA. | last4 = Ahmad | first4 = Z. | last5 = Hamid | first5 = S. | last6 = Jafri | first6 = W. | title = The clinical, endoscopic and histological spectrum of the solitary rectal ulcer syndrome: a single-center experience of 116 cases. | journal = BMC Gastroenterol | volume = 12 | issue =  | pages = 72 | month =  | year = 2012 | doi = 10.1186/1471-230X-12-72 | PMID = 22697798 }}</ref>
*''[[Mucosal prolapse syndrome]]'' may be used as a synonym; however, it encompasses other entities.<ref name=pmid22697798>{{Cite journal  | last1 = Abid | first1 = S. | last2 = Khawaja | first2 = A. | last3 = Bhimani | first3 = SA. | last4 = Ahmad | first4 = Z. | last5 = Hamid | first5 = S. | last6 = Jafri | first6 = W. | title = The clinical, endoscopic and histological spectrum of the solitary rectal ulcer syndrome: a single-center experience of 116 cases. | journal = BMC Gastroenterol | volume = 12 | issue =  | pages = 72 | month =  | year = 2012 | doi = 10.1186/1471-230X-12-72 | PMID = 22697798 }}</ref>
===General===
{{Main|Solitary rectal ulcer}}
*Clinically may be suspected to a malignancy - biopsied routinely.
*Mucosal ulceration.
*"Three-lies disease":<ref name=pmid18271667>{{cite journal |author=Crespo Pérez L, Moreira Vicente V, Redondo Verge C, López San Román A, Milicua Salamero JM |title=["The three-lies disease": solitary rectal ulcer syndrome] |language=Spanish; Castilian |journal=Rev Esp Enferm Dig |volume=99 |issue=11 |pages=663–6 |year=2007 |month=November |pmid=18271667 |doi= |url=http://www.grupoaran.com/mrmUpdate/lecturaPDFfromXML.asp?IdArt=459864&TO=RVN&Eng=1}}</ref>
# May not be solitary.
# May not be rectal -- can be in left colon.
# May not be ulcerating -- non-ulcerated lesions: polypoid and/or erythematous.
 
Note: Each of the words in ''solitary rectal ulcer'' is a lie.
 
====Epidemiology====
*Typically younger patients - average age of presentation ~30 years in one study.<ref name=pmid17139403>{{cite journal |author=Chong VH, Jalihal A |title=Solitary rectal ulcer syndrome: characteristics, outcomes and predictive profiles for persistent bleeding per rectum |journal=Singapore Med J |volume=47 |issue=12 |pages=1063–8 |year=2006 |month=December |pmid=17139403 |doi= |url=http://www.sma.org.sg/smj/4712/4712a7.pdf}}</ref>
*Rare.
 
====Clinical presentation====
*Usually presents as BRBPR ~ 85% of cases.<ref name=pmid17139403/>
*Abdominal pain present in approx. 1/3.<ref name=pmid17139403/>
**May be very painful.
 
Treatment:
*Usually conservative, i.e. non-surgical.
*Resection - may be done for fear of malignancy.
 
===Gross===
*Classically, anterior or anterolateral wall of the rectum.<ref name=pmid18271667/>
 
===Microscopic===
Features:<ref name=pmid18271667/><ref name=pmid2091997>{{Cite journal  | last1 = Malik | first1 = AK. | last2 = Bhaskar | first2 = KV. | last3 = Kochhar | first3 = R. | last4 = Bhasin | first4 = DK. | last5 = Singh | first5 = K. | last6 = Mehta | first6 = SK. | last7 = Datta | first7 = BN. | title = Solitary ulcer syndrome of the rectum--a histopathologic characterisation of 33 biopsies. | journal = Indian J Pathol Microbiol | volume = 33 | issue = 3 | pages = 216-20 | month = Jul | year = 1990 | doi =  | PMID = 2091997 }}</ref>
*Fibrosis of the lamina propria.
*Thickened muscularis mucosa with abnormal extension to the lumen.
*+/-Mucosa ulceration.
*+/-Submucosal fibrosis.
 
DDx:
*[[Inflammatory pseudopolyp]] (inflammatory polyp).
**Associated with [[inflammatory bowel disease]].
*[[Rectal prolapse]].
*Well-differentiated [[colonic adenocarcinoma|adenocarcinoma]].
 
===IHC===
*p53 -ve.
**May be used to help exclude adenocarcinoma.


==Rectal prolapse==
==Rectal prolapse==
===General===
{{Main|Rectal prolapse}}
*Usually close to the anal verge.
*Rare forms can occasionally be confused with [[colorectal carcinoma|cancer]].<ref name=pmid19861563>{{cite journal |author=Brosens LA, Montgomery EA, Bhagavan BS, Offerhaus GJ, Giardiello FM |title=Mucosal prolapse syndrome presenting as rectal polyposis |journal=J. Clin. Pathol. |volume=62 |issue=11 |pages=1034–6 |year=2009 |month=November |pmid=19861563 |pmc=2853932 |doi=10.1136/jcp.2009.067801 |url=}}</ref>
 
===Microscopic===
Features:<ref name=pmid3234303>{{cite journal |author=Schneider A, Fritze C, Bosseckert H, Machnik G |title=[Primary clinical, endoscopic and histologic findings in solitary rectal ulcer] |language=German |journal=Dtsch Z Verdau Stoffwechselkr |volume=48 |issue=3-4 |pages=183–9 |year=1988 |pmid=3234303 |doi= |url=}}</ref>
*"Fibromuscular hyperplasia" - '''key feature''':
**Fibrosis (submucosa, lamina propria).
**Muscularis mucosae is "too superficial" (muscle in the lamina propria).
*Surface ulceration + inflammation ([[neutrophil]]s).
*+/-Serration of epithelium at the surface.
 
Notes:
*'''Important negative''': no nuclear atypia.
 
====Images====
<gallery>
Image:Rectal_prolapse_-_low_mag.jpg | Rectal prolapse - low mag. (WC/Nephon)
Image:Rectal_prolapse_-_intermed_mag.jpg | Rectal prolapse - intermed. mag. (WC/Nephron)
</gallery>


=Neoplastic disease=
=Neoplastic disease=
Line 873: Line 284:


=Other=
=Other=
==Colonic pseudo-obstruction==
{{Main|Colonic pseudo-obstruction}}
==Pseudomelanosis coli==
==Pseudomelanosis coli==
*AKA ''melanosis coli''.<ref>URL: [http://www.medicinenet.com/melanosis_coli/article.htm http://www.medicinenet.com/melanosis_coli/article.htm]. Accessed on: 4 March 2011.</ref>
*[[AKA]] ''melanosis coli''.
===General===
{{Main|Pseudomelanosis coli}}
*''Not melanin'' as the name ''melanosis coli'' suggests; it is actually lipofuscin (in macrophages).<ref name=pmid18666316>{{cite journal |author=Freeman HJ |title="Melanosis" in the small and large intestine |journal=World J. Gastroenterol. |volume=14 |issue=27 |pages=4296-9 |year=2008 |month=July |pmid=18666316 |doi= |url=http://www.wjgnet.com/1007-9327/14/4296.asp}}</ref>
*Endoscopist may see brown pigmentation of mucosa and suspect the diagnosis.
*Presence may lead to endoscopic misinterpretation of colitis severity.<ref name=pmid21375218>{{Cite journal  | last1 = Zapatier | first1 = JA. | last2 = Schneider | first2 = A. | last3 = Parra | first3 = JL. | title = Overestimation of ulcerative colitis due to melanosis coli. | journal = Acta Gastroenterol Latinoam | volume = 40 | issue = 4 | pages = 351-3 | month = Dec | year = 2010 | doi =  | PMID = 21375218 }}</ref>
 
====Epidemiology====
*Classically associated with anthracene containing laxative (e.g. Senokot) use and herbal remedies.<ref name=pmid18666316/>
**May be seen in individuals not using laxatives.<ref name=pmid9600362/>
*Seen in (long-standing) [[inflammatory bowel disease]], especially [[ulcerative colitis]].<ref name=pmid9600362>{{Cite journal  | last1 = Pardi | first1 = DS. | last2 = Tremaine | first2 = WJ. | last3 = Rothenberg | first3 = HJ. | last4 = Batts | first4 = KP. | title = Melanosis coli in inflammatory bowel disease. | journal = J Clin Gastroenterol | volume = 26 | issue = 3 | pages = 167-70 | month = Apr | year = 1998 | doi =  | PMID = 9600362 }}</ref>
 
===Gross===
*Brown pigmentation of the mucosa, esp. cecum and proximal colon.
 
====Image====
<gallery>
Image:Melanosis_coli.jpg | Melanosis coli - endoscopic image (WC)
</gallery>
===Microscopic===
Features:
*Brown granular pigment - in the lamina propria.
**Typically more prominent in the cecum and proximal colon.<ref name=pmid18666316/>
 
Notes:
*DDx of brown pigment:
**Lipofuscin - comes with age (can be demonstrated with a ''[[PAS stain]]''<ref name=pmid5463681 >{{cite journal |author=Kovi J, Leifer C |title=Lipofuscin pigment accumulation in spontaneous mammary carcinoma of A/Jax mouse |journal=J Natl Med Assoc |volume=62 |issue=4 |pages=287–90 |year=1970 |month=July |pmid=5463681 |pmc=2611776 |doi= |url=http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2611776/pdf/jnma00512-0077.pdf}}</ref> or ''[[Kluver-Barrera stain]]''<ref>URL: [http://education.vetmed.vt.edu/curriculum/VM8054/labs/Lab2/Examples/exkluvbarr.htm http://education.vetmed.vt.edu/curriculum/VM8054/labs/Lab2/Examples/exkluvbarr.htm]. Accessed on: 5 May 2010.</ref>).
***Melanosis coli.
**Old haemorrhage, i.e. hemosiderin-laden macrophages (may be demonstrated with ''[[Prussian blue stain]]''<ref>URL: [http://education.vetmed.vt.edu/curriculum/VM8054/labs/Lab2/Examples/exprussb.htm http://education.vetmed.vt.edu/curriculum/VM8054/labs/Lab2/Examples/exprussb.htm]. Accessed on: 5 May 2010.</ref>).
**Melanin (from melanocytes) - rare in colon (may be demonstrated with a ''[[Fontana-Masson stain]]''<ref>URL: [http://education.vetmed.vt.edu/curriculum/VM8054/labs/Lab2/Examples/exfontana.htm http://education.vetmed.vt.edu/curriculum/VM8054/labs/Lab2/Examples/exfontana.htm]. Accessed on: 5 May 2010.</ref> -- though not so useful in the GI tract).
**Foreign material (e.g. tattoo pigment) - not seen in GI tract.
 
====Images====
<gallery>
Image:Melanosis_coli_high_mag.jpg | Melanosis coli - high mag. (WC/Nephron)
Image:Melanosis_coli_low_mag.jpg | Melanosis coli - low mag. (WC/Nephron)
</gallery>
===Stains===
*Can be demonstrated with a [[PAS stain]].<ref name=pmid9283862>{{cite journal |author=Benavides SH, Morgante PE, Monserrat AJ, Zárate J, Porta EA |title=The pigment of melanosis coli: a lectin histochemical study |journal=Gastrointest. Endosc. |volume=46 |issue=2 |pages=131–8 |year=1997 |month=August |pmid=9283862 |doi= |url=}}</ref>
 
===Sign out===
<pre>
ASCENDING COLON, BIOPSY:
- PSEUDOMELANOSIS COLI.
- NEGATIVE FOR ACTIVE COLITIS.
- NEGATIVE FOR DYSPLASIA.
</pre>


==Angiodysplasia==
==Angiodysplasia==
===General===
{{Main|Angiodysplasia}}
*Causes (lower) GI haemorrhage.
*Generally, not a problem pathologists see.
*May be associated with [[aortic stenosis]]; known as ''Heyde syndrome''.<ref name=pmid19652242>{{cite journal |author=Hui YT, Lam WM, Fong NM, Yuen PK, Lam JT |title=Heyde's syndrome: diagnosis and management by the novel single-balloon enteroscopy |journal=Hong Kong Med J |volume=15 |issue=4 |pages=301–3 |year=2009 |month=August |pmid=19652242 |doi= |url=http://www.hkmj.org/abstracts/v15n4/301.htm}}</ref>
 
Epidemiology:
*Older people.
 
Etiology:
*Thought to be caused by the higher wall tension of cecum (due to larger diameter) and result from (intermittent) venous occlusion/focal dilation of vessels.<ref name=Ref_PBoD854>{{Ref PBoD|854}}</ref>
 
===Gross===
*Cecum - classic location.
 
Note:
*[[Crohn's disease]] - may mimic angiodysplasia radiographically.<ref name=pmid3054852/>
 
===Microscopic===
Features:<ref name=pmid3054852>{{Cite journal  | last1 = Hemingway | first1 = AP. | title = Angiodysplasia: current concepts. | journal = Postgrad Med J | volume = 64 | issue = 750 | pages = 259-63 | month = Apr | year = 1988 | doi =  | PMID = 3054852 }}</ref>
*Dilated vessels in mucosa and submucosa.


==Drugs==
==Drugs==
Line 1,030: Line 381:
*[[Intestinal polyps]].
*[[Intestinal polyps]].
*[[Small bowel]].
*[[Small bowel]].
*[[Doughnuts]].


=References=
=References=
Line 1,035: Line 387:


[[Category:Gastrointestinal pathology]]
[[Category:Gastrointestinal pathology]]
[[Category:Colon|Colon]]
Michael
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