Difference between revisions of "Colorectal tumours"

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'''Colorectal tumours''', especially '''colorectal carcinomas''', are very common.  They are the bread and butter of GI pathology.  Non-tumour colon is dealt with in the ''[[colon]]'' article.
'''Colorectal tumours''', especially '''colorectal carcinomas''', are very common.  They are the bread and butter of GI pathology.  Non-tumour colon is dealt with in the ''[[colon]]'' article.
''Colonic tumours'' and ''rectal tumours'' redirect here.


An introduction to gastrointestinal pathology is in the ''[[gastrointestinal pathology]]'' article.  The precursor lesion of colorectal carcinoma (CRC) is, typically, an [[adenomatous polyps|adenomatous polyp]].  Polyps are discussed in the ''[[intestinal polyps]]'' article.  
An introduction to gastrointestinal pathology is in the ''[[gastrointestinal pathology]]'' article.  The precursor lesion of colorectal carcinoma (CRC) is, typically, an [[adenomatous polyps|adenomatous polyp]].  Polyps are discussed in the ''[[intestinal polyps]]'' article.  
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==Microsatellite instability cancers==
==Microsatellite instability cancers==
*Abbreviated ''MSI cancers''.
*Abbreviated ''MSI cancers''.
===General===
{{Main|Microsatellite instability in colorectal cancer}}
*National Comprehensive Cancer Network (NCCN) in the USA recommends testing all individual with colorectal cancer that are under the age of 70 years.<ref>URL: [http://www.medscape.com/viewarticle/821981 http://www.medscape.com/viewarticle/821981]. Accessed on: 12 January 2016.</ref> 
*A draft document (2015) from CAP, ASCO suggests testing all colorectal cancer cases for MSI.<ref>URL: [http://www.amp.org/committees/clinical_practice/documents/20150327CRCMMDraftRecommendationsforOCP-UPDATEDfinaldraft_001.pdf http://www.amp.org/committees/clinical_practice/documents/20150327CRCMMDraftRecommendationsforOCP-UPDATEDfinaldraft_001.pdf]. Accessed on: 12 January 2016.</ref>
*In Canada the guidelines vary by the province.<ref>URL: [http://www.ncbi.nlm.nih.gov/books/NBK321468/ http://www.ncbi.nlm.nih.gov/books/NBK321468/]. Accessed on: 12 January 2016.</ref>
*Can be sporadic, i.e. non-syndromic.<ref name=pmid24199172>{{Cite journal  | last1 = Heinimann | first1 = K. | title = Toward a Molecular Classification of Colorectal Cancer: The Role of Microsatellite Instability Status. | journal = Front Oncol | volume = 3 | issue =  | pages = 272 | month =  | year = 2013 | doi = 10.3389/fonc.2013.00272 | PMID = 24199172 }}</ref>
*Strong association with [[Lynch syndrome]].<ref>{{Cite journal  | last1 = Mensenkamp | first1 = AR. | last2 = Vogelaar | first2 = IP. | last3 = van Zelst-Stams | first3 = WA. | last4 = Goossens | first4 = M. | last5 = Ouchene | first5 = H. | last6 = Hendriks-Cornelissen | first6 = SJ. | last7 = Kwint | first7 = MP. | last8 = Hoogerbrugge | first8 = N. | last9 = Nagtegaal | first9 = ID. | title = Somatic mutations in MLH1 and MSH2 are a Frequent Cause of Mismatch-repair Deficiency in Lynch Syndrome-like Tumors. | journal = Gastroenterology | volume =  | issue =  | pages =  | month = Dec | year = 2013 | doi = 10.1053/j.gastro.2013.12.002 | PMID = 24333619 }}</ref><ref name=pmid24199172/>


Features:<ref name=pmid20420947>{{cite journal |author=Boland CR, Goel A |title=Microsatellite instability in colorectal cancer |journal=Gastroenterology |volume=138 |issue=6 |pages=2073–2087.e3 |year=2010 |month=June |pmid=20420947 |doi=10.1053/j.gastro.2009.12.064 |url=}}</ref>
=Specific entities=
*Prognosis: slightly better than other [[CRC]] without MSI.
==Colorectal adenocarcinoma==
*Treatment implication: different response to chemotherapy.
*[[AKA]] ''colorectal adenocarcinoma not otherwise specified''.
*[[AKA]] ''colorectal carcinoma'', abbreviated ''CRC''.
{{Main|Colorectal adenocarcinoma}}


====MSI classification====
==Secondary colorectal cancer==
MSI associated cancers can be classified into:<ref name=pmid16106253>{{cite journal |author=Lawes DA, Pearson T, Sengupta S, Boulos PB |title=The role of MLH1, MSH2 and MSH6 in the development of multiple colorectal cancers |journal=Br. J. Cancer |volume=93 |issue=4 |pages=472–7 |year=2005 |month=August |pmid=16106253 |pmc=2361590 |doi=10.1038/sj.bjc.6602708 |url=}}</ref><ref name=pmid11438476>{{cite journal |author=Guidoboni M, Gafà R, Viel A, ''et al.'' |title=Microsatellite instability and high content of activated cytotoxic lymphocytes identify colon cancer patients with a favorable prognosis |journal=Am. J. Pathol. |volume=159 |issue=1 |pages=297–304 |year=2001 |month=July |pmid=11438476 |pmc=1850401 |doi= |url=}}</ref>
===General===
*MSI-H >= 30% of loci have abnormality.
*Uncommon.
*MSI-L <30% of loci have abnormality.
*May be suspected.
 
Note:
*In the context of '''''no''''' chemotherapy, individuals with MSI-H tumours have a superior outcome to those with MSI-L tumours.<ref name=pmid12867608>{{Cite journal  | last1 = Ribic | first1 = CM. | last2 = Sargent | first2 = DJ. | last3 = Moore | first3 = MJ. | last4 = Thibodeau | first4 = SN. | last5 = French | first5 = AJ. | last6 = Goldberg | first6 = RM. | last7 = Hamilton | first7 = SR. | last8 = Laurent-Puig | first8 = P. | last9 = Gryfe | first9 = R. | title = Tumor microsatellite-instability status as a predictor of benefit from fluorouracil-based adjuvant chemotherapy for colon cancer. | journal = N Engl J Med | volume = 349 | issue = 3 | pages = 247-57 | month = Jul | year = 2003 | doi = 10.1056/NEJMoa022289 | PMID = 12867608 }}</ref>
**With chemotherapy the outcomes are similar.
 
===Gross===
Features:<ref name=pmid20420947>{{cite journal |author=Boland CR, Goel A |title=Microsatellite instability in colorectal cancer |journal=Gastroenterology |volume=138 |issue=6 |pages=2073–2087.e3 |year=2010 |month=June |pmid=20420947 |doi=10.1053/j.gastro.2009.12.064 |url=}}</ref>
*Location: proximal colon, i.e. right-sided, predominance.


===Microscopic===
===Microscopic===
Features:<ref name=pmid20420947>{{cite journal |author=Boland CR, Goel A |title=Microsatellite instability in colorectal cancer |journal=Gastroenterology |volume=138 |issue=6 |pages=2073–2087.e3 |year=2010 |month=June |pmid=20420947 |doi=10.1053/j.gastro.2009.12.064 |url=}}</ref>
Features:
*Lymphocytic infiltrate - see ''[[intratumoural lymphocytic response]]''.
*Normal colorectal mucosa.
*Large peritumoural collections of lymphocytes - see ''[[peritumoural lymphocytic response]]''.
*Atypical cells in the lamina propria or submucosa.
*Pushing border.<ref>Pollet, A. 18 October 2010.</ref>
*Histomorphology:
**Poorly differentiated.
**Mucinous.
**[[Signet ring cell carcinoma|Signet ring]].
**Medullary.<ref name=pmid18283560>{{cite journal |author=Truta B, Chen YY, Blanco AM, ''et al.'' |title=Tumor histology helps to identify Lynch syndrome among colorectal cancer patients |journal=Fam. Cancer |volume=7 |issue=3 |pages=267–74 |year=2008 |pmid=18283560 |doi=10.1007/s10689-008-9186-8 |url=}}</ref>


===Molecular===
DDx:
Commonly associated abnormalities in the genes:
*Colorectal neuroendocrine tumour.
#MLH1.
#PMS2.
#MSH2.
#MSH6.
Less common abnormalities:
#PMS1.
#MLH3.
#MSH3.


===IHC===
===Images===
Immunostains are commonly done for:
<gallery>
*MLH1.
Image:Prostate carcinoma in rectum -- very low mag.jpg | Pca in rectum - very low mag. (WC)
*PMS2.
Image:Prostate carcinoma in rectum -- low mag.jpg | Pca in rectum - low mag. (WC)
*MSH2.
Image:Prostate carcinoma in rectum -- intermed mag.jpg | Pca in rectum - intermed. mag. (WC)
*MSH6.
Image:Prostate carcinoma in rectum -- high mag.jpg | Pca in rectum - high mag. (WC)
 
</gallery>
IHC interpretation:
<gallery>
*'''Loss of nuclear staining''' in nuclei of the tumour ''implies'' a mutation.
Image:Prostate carcinoma in rectum - PSAP -- intermed mag.jpg | Pca in rectum - PSAP - intermed. mag. (WC)
**Nuclear staining = normal.
Image:Prostate carcinoma in rectum - PSA -- intermed mag.jpg | Pca in rectum - PSA - intermed. mag. (WC)
* Patchy MSH6 is considered normal.{{fact}}<!-- possibly PMID 21297438 -->
Image:Prostate carcinoma in rectum - CK20 -- intermed mag.jpg | Pca in rectum - CK20 - intermed. mag. (WC)
 
</gallery>
MSI staining loss patterns:<ref name=pmid20632815/>
*MLH1 and PMS2 are often lost together, as MLH1 loss results in PMS2 loss.
*MSH2 and MSH6 are often lost together, as MSH2 loss results in MSH6 loss.
 
Implication of MSI staining loss patterns:  
*PMS2 & MSH6 can be used as a screen.<ref name=pmid20632815>{{Cite journal  | last1 = Hall | first1 = G. | last2 = Clarkson | first2 = A. | last3 = Shi | first3 = A. | last4 = Langford | first4 = E. | last5 = Leung | first5 = H. | last6 = Eckstein | first6 = RP. | last7 = Gill | first7 = AJ. | title = Immunohistochemistry for PMS2 and MSH6 alone can replace a four antibody panel for mismatch repair deficiency screening in colorectal adenocarcinoma. | journal = Pathology | volume = 42 | issue = 5 | pages = 409-13 | month =  | year = 2010 | doi = 10.3109/00313025.2010.493871 | PMID = 20632815 }}</ref>
 
====Etiology/significance loss of staining====
*MSH2 mutations (IHC stain -ve) - often associated with a germline mutation,<ref name=pmid16216036>{{cite journal |author=Mangold E, Pagenstecher C, Friedl W, ''et al.'' |title=Tumours from MSH2 mutation carriers show loss of MSH2 expression but many tumours from MLH1 mutation carriers exhibit weak positive MLH1 staining |journal=J. Pathol. |volume=207 |issue=4 |pages=385–95 |year=2005 |month=December |pmid=16216036 |doi=10.1002/path.1858 |url=}}</ref> while mutations in MLH1 are usually sporatic.<ref>A. Pollett. 2010.</ref>
*PMS2 mutations (IHC stain -ve) - often associated with a germline mutation.<ref name=pmid20205264>{{cite journal |author=Vaughn CP, Robles J, Swensen JJ, ''et al.'' |title=Clinical analysis of PMS2: mutation detection and avoidance of pseudogenes |journal=Hum. Mutat. |volume=31 |issue=5 |pages=588–93 |year=2010 |month=May |pmid=20205264 |doi=10.1002/humu.21230 |url=}}</ref>
 
How to remember the more important MSI stuff:
*The ''MSHs'' are paired together.
**''MSH'' (Mount Sinai Hospital) is where they started it in the city.
**''PMS'' sucks... it's with the other one (MLH).
*The higher numbers in the pairings ('''P'''MS2, '''M'''SH6) are the screening tests ('''''H'''igh Screen '''P'''ass'').
*The ''2''s (MSH2, PMS2) are associated with germline mutations (''Four legs good two legs bad!'').
 
=Specific entities=
==Colorectal adenocarcinoma==
*[[AKA]] ''colorectal adenocarcinoma not otherwise specified''.
*[[AKA]] ''colorectal carcinoma'', abbreviated ''CRC''.
{{Main|Colorectal adenocarcinoma}}


=See also=
=See also=
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*[[Gastrointestinal pathology]].
*[[Gastrointestinal pathology]].
*[[Tumour budding]].
*[[Tumour budding]].
*[[Tumour perforation in colorectal cancer]].
*[[Transanal minimally invasive surgery]].


=References=
=References=

Latest revision as of 16:50, 29 August 2018

Colorectal tumours, especially colorectal carcinomas, are very common. They are the bread and butter of GI pathology. Non-tumour colon is dealt with in the colon article.

Colonic tumours and rectal tumours redirect here.

An introduction to gastrointestinal pathology is in the gastrointestinal pathology article. The precursor lesion of colorectal carcinoma (CRC) is, typically, an adenomatous polyp. Polyps are discussed in the intestinal polyps article.

Classification

Most common

Others

Other tumours - many (incomplete list):[2]

Notes:

Squamous carcinoma

Main article: Squamous carcinoma
  • Rare.
    • In the context of a rectal tumour, retrograde growth from the anus should be considered.

Staging of colorectal cancer

Main article: Colorectal cancer staging

Pathogenesis of colorectal carcinoma

Overview

Colorectal carcinoma is thought to arise from one of two pathways:[4][5]

  1. APC (adenomatous polyposis coli) gene mutation pathway, AKA classic adenoma-carcinoma pathway.
  2. Serrated pathway, AKA mutator pathway, mismatch repair pathway.

Syndromes

Both of the above described pathways are associated with syndromes:

  1. Familial adenomatous polyposis (FAP) or familial polyposis coli (FPC).
  2. Lynch syndrome (AKA hereditary non-polyposis colorectal cancer syndrome (HNPCC)).

Pathways

APC gene mutation pathway

Microscopic:

Mismatch repair pathway

Other ancillary studies

BRAF V600E mutation

Main article: BRAF V600E mutation

Features:[6]

  • Independently associated with BRAF V600E:
    • Usually older (>70 years old).
    • Female gender.
    • Right-sided tumour location.
  • Worse prognosis - in the context of metastatic disease.

KRAS mutation

Main article: KRAS mutation

Features:[7][8]

  • Patient must have wild type KRAS to get drugs; KRAS mutation predicts resistance to cetuximab (Erbitux) and panitumumab (Vectibix).

Microsatellite instability cancers

  • Abbreviated MSI cancers.
Main article: Microsatellite instability in colorectal cancer

Specific entities

Colorectal adenocarcinoma

  • AKA colorectal adenocarcinoma not otherwise specified.
  • AKA colorectal carcinoma, abbreviated CRC.
Main article: Colorectal adenocarcinoma

Secondary colorectal cancer

General

  • Uncommon.
  • May be suspected.

Microscopic

Features:

  • Normal colorectal mucosa.
  • Atypical cells in the lamina propria or submucosa.

DDx:

  • Colorectal neuroendocrine tumour.

Images

  • Pca in rectum - very low mag. (WC)

  • Pca in rectum - low mag. (WC)

  • Pca in rectum - intermed. mag. (WC)

  • Pca in rectum - high mag. (WC)

  • Pca in rectum - PSAP - intermed. mag. (WC)

  • Pca in rectum - PSA - intermed. mag. (WC)

  • Pca in rectum - CK20 - intermed. mag. (WC)

See also

References

  1. ↑ Cotran, Ramzi S.; Kumar, Vinay; Fausto, Nelson; Nelso Fausto; Robbins, Stanley L.; Abbas, Abul K. (2005). Robbins and Cotran pathologic basis of disease (7th ed.). St. Louis, Mo: Elsevier Saunders. pp. 864. ISBN 0-7216-0187-1.
  2. ↑ Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 198. ISBN 978-0781765275.
  3. ↑ Tozawa E, Ajioka Y, Watanabe H, et al. (2007). "Mucin expression, p53 overexpression, and peritumoral lymphocytic infiltration of advanced colorectal carcinoma with mucus component: is mucinous carcinoma a distinct histological entity?". Pathol. Res. Pract. 203 (8): 567–74. doi:10.1016/j.prp.2007.04.013. PMID 17679024.
  4. ↑ Goldstein NS (January 2006). "Serrated pathway and APC (conventional)-type colorectal polyps: molecular-morphologic correlations, genetic pathways, and implications for classification". Am. J. Clin. Pathol. 125 (1): 146–53. PMID 16483003.
  5. ↑ Rüschoff J, Aust D, Hartmann A (2007). "[Colorectal serrated adenoma: diagnostic criteria and clinical implications]" (in German). Verh Dtsch Ges Pathol 91: 119–25. PMID 18314605.
  6. ↑ 6.0 6.1 Tie J, Gibbs P, Lipton L, et al. (July 2010). "Optimizing targeted therapeutic development: Analysis of a colorectal cancer patient population with the BRAF(V600E) mutation". Int J Cancer. doi:10.1002/ijc.25555. PMID 20635392.
  7. ↑ Dunn EF, Iida M, Myers RA, et al. (October 2010). "Dasatinib sensitizes KRAS mutant colorectal tumors to cetuximab". Oncogene. doi:10.1038/onc.2010.430. PMID 20956938.
  8. ↑ Di Nicolantonio F, Martini M, Molinari F, et al. (December 2008). "Wild-type BRAF is required for response to panitumumab or cetuximab in metastatic colorectal cancer". J. Clin. Oncol. 26 (35): 5705–12. doi:10.1200/JCO.2008.18.0786. PMID 19001320.
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