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'''Colorectal tumours''' 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. | |||
Other tumours - many (incomplete list):<ref>{{Ref WMSP|198}}</ref> | =Classification= | ||
*Mucinous carcinoma. | ===Most common=== | ||
*Adenosquamous carcinoma. | *Colon & rectum - most common = [[colorectal adenocarcinoma|adenocarinoma]].<ref name=Ref_PBoD864>{{Ref PBoD|864}}</ref> | ||
===Others=== | |||
Other tumours - many (incomplete list):<ref name=Ref_WMSP198>{{Ref WMSP|198}}</ref> | |||
*[[Mucinous carcinoma]]. | |||
**Need > 50% mucinous component.<ref name=pmid17679024 >{{cite journal |author=Tozawa E, Ajioka Y, Watanabe H, ''et al.'' |title=Mucin expression, p53 overexpression, and peritumoral lymphocytic infiltration of advanced colorectal carcinoma with mucus component: is mucinous carcinoma a distinct histological entity? |journal=Pathol. Res. Pract. |volume=203 |issue=8 |pages=567–74 |year=2007 |pmid=17679024 |doi=10.1016/j.prp.2007.04.013 |url=}}</ref> | |||
*[[Adenosquamous carcinoma]]. | |||
*Signet-ring carcinoma. | *Signet-ring carcinoma. | ||
*Squamous carcinoma. | *Squamous carcinoma. | ||
*Neuroendocrine | *[[Neuroendocrine neoplasm]]s (carcinoid tumours). | ||
*Lipoma. | *[[Lipoma]]. | ||
*Leiomyoma. | *[[Leiomyoma]]. | ||
*[[Gastrointestinal stromal tumour]] (GIST) - dealt with in a separate article. | *[[Gastrointestinal stromal tumour]] (GIST) - dealt with in a separate article. | ||
*Angiosarcoma. | *[[Angiosarcoma]]. | ||
*Lymphoma (Non-Hodgkin's lymphoma). | *Lymphoma (Non-Hodgkin's lymphoma). | ||
Notes: | |||
* | *[[Mucinous carcinoma]] - percentage required to call varies by site: | ||
====Squamous carcinoma==== | |||
{{Main|Squamous carcinoma}} | |||
* | *Rare. | ||
** | **In the context of a rectal tumour, retrograde growth from the [[anus]] should be considered. | ||
==Staging of colorectal cancer== | ==Staging of colorectal cancer== | ||
{{Main|Colorectal cancer staging}} | |||
==Pathogenesis of colorectal carcinoma== | |||
==Pathogenesis== | |||
===Overview=== | ===Overview=== | ||
Colorectal carcinoma is thought to arise from one of two pathways:<ref name=pmid16483003>{{cite journal |author=Goldstein NS |title=Serrated pathway and APC (conventional)-type colorectal polyps: molecular-morphologic correlations, genetic pathways, and implications for classification |journal=Am. J. Clin. Pathol. |volume=125 |issue=1 |pages=146–53 |year=2006 |month=January |pmid=16483003 |doi= |url=}}</ref><ref name=pmid18314605>{{cite journal |author=Rüschoff J, Aust D, Hartmann A |title=[Colorectal serrated adenoma: diagnostic criteria and clinical implications] |language=German |journal=Verh Dtsch Ges Pathol |volume=91 |issue= |pages=119–25 |year=2007 |pmid=18314605 |doi= |url=}}</ref> | Colorectal carcinoma is thought to arise from one of two pathways:<ref name=pmid16483003>{{cite journal |author=Goldstein NS |title=Serrated pathway and APC (conventional)-type colorectal polyps: molecular-morphologic correlations, genetic pathways, and implications for classification |journal=Am. J. Clin. Pathol. |volume=125 |issue=1 |pages=146–53 |year=2006 |month=January |pmid=16483003 |doi= |url=}}</ref><ref name=pmid18314605>{{cite journal |author=Rüschoff J, Aust D, Hartmann A |title=[Colorectal serrated adenoma: diagnostic criteria and clinical implications] |language=German |journal=Verh Dtsch Ges Pathol |volume=91 |issue= |pages=119–25 |year=2007 |pmid=18314605 |doi= |url=}}</ref> | ||
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#Serrated pathway, AKA mutator pathway, mismatch repair pathway. | #Serrated pathway, AKA mutator pathway, mismatch repair pathway. | ||
=== | ====Syndromes==== | ||
Both of the above described pathways are associated with syndromes: | |||
#''[[Familial adenomatous polyposis]]'' (FAP) or ''familial polyposis coli'' (FPC). | |||
# | #''Lynch syndrome'' ([[AKA]] ''[[hereditary non-polyposis colorectal cancer syndrome]]'' (HNPCC)). | ||
# | |||
===Pathways=== | |||
====APC gene mutation pathway==== | |||
Microscopic: | |||
*[[Adenomatous polyps]]. | |||
====Mismatch repair pathway==== | |||
* | *Associated with [[microsatellite instability]] (MSI). | ||
===Other ancillary studies=== | ===Other ancillary studies=== | ||
*BRAF ''V600E'' missense mutation found in ~10% CRC.<ref name=pmid20635392>{{cite journal |author=Tie J, Gibbs P, Lipton L, ''et al.'' |title=Optimizing targeted therapeutic development: Analysis of a colorectal cancer patient population with the BRAF(V600E) mutation |journal=Int J Cancer |volume= |issue= |pages= |year=2010 |month=July |pmid=20635392 |doi=10.1002/ijc.25555 |url=}}</ref> | *BRAF ''V600E'' missense mutation found in ~10% CRC.<ref name=pmid20635392>{{cite journal |author=Tie J, Gibbs P, Lipton L, ''et al.'' |title=Optimizing targeted therapeutic development: Analysis of a colorectal cancer patient population with the BRAF(V600E) mutation |journal=Int J Cancer |volume= |issue= |pages= |year=2010 |month=July |pmid=20635392 |doi=10.1002/ijc.25555 |url=}}</ref> | ||
*KRAS mutation status. | *[[KRAS mutation]] status. | ||
====BRAF V600E mutation==== | ====BRAF V600E mutation==== | ||
{{Main|BRAF V600E mutation}} | |||
Features:<ref name=pmid20635392/> | Features:<ref name=pmid20635392/> | ||
*Independently | *Independently associated with BRAF V600E: | ||
**Usually older (>70 years old). | **Usually older (>70 years old). | ||
**Female gender | **Female gender. | ||
**Right-sided tumour location. | **Right-sided tumour location. | ||
*Worse prognosis - in the context of metastatic disease. | *Worse prognosis - in the context of metastatic disease. | ||
====KRAS mutation==== | ====KRAS mutation==== | ||
{{Main|KRAS mutation}} | |||
Features:<ref name=pmid20956938>{{cite journal |author=Dunn EF, Iida M, Myers RA, ''et al.'' |title=Dasatinib sensitizes KRAS mutant colorectal tumors to cetuximab |journal=Oncogene |volume= |issue= |pages= |year=2010 |month=October |pmid=20956938 |doi=10.1038/onc.2010.430 |url=}}</ref><ref name=pmid19001320>{{cite journal |author=Di Nicolantonio F, Martini M, Molinari F, ''et al.'' |title=Wild-type BRAF is required for response to panitumumab or cetuximab in metastatic colorectal cancer |journal=J. Clin. Oncol. |volume=26 |issue=35 |pages=5705–12 |year=2008 |month=December |pmid=19001320 |doi=10.1200/JCO.2008.18.0786 |url=}}</ref> | Features:<ref name=pmid20956938>{{cite journal |author=Dunn EF, Iida M, Myers RA, ''et al.'' |title=Dasatinib sensitizes KRAS mutant colorectal tumors to cetuximab |journal=Oncogene |volume= |issue= |pages= |year=2010 |month=October |pmid=20956938 |doi=10.1038/onc.2010.430 |url=}}</ref><ref name=pmid19001320>{{cite journal |author=Di Nicolantonio F, Martini M, Molinari F, ''et al.'' |title=Wild-type BRAF is required for response to panitumumab or cetuximab in metastatic colorectal cancer |journal=J. Clin. Oncol. |volume=26 |issue=35 |pages=5705–12 |year=2008 |month=December |pmid=19001320 |doi=10.1200/JCO.2008.18.0786 |url=}}</ref> | ||
*Patient must have ''wild type'' KRAS to get drugs; KRAS mutation predicts resistance to cetuximab (Erbitux) and panitumumab (Vectibix). | *Patient must have ''wild type'' KRAS to get drugs; KRAS mutation predicts resistance to [[cetuximab]] (Erbitux) and [[panitumumab]] (Vectibix). | ||
**Cetuximab and panitumumab are EGFR inhibitors. | **Cetuximab and panitumumab are [[EGFR inhibitors]]. | ||
== | ==Microsatellite instability cancers== | ||
*Abbreviated ''MSI cancers''. | |||
{{Main|Microsatellite instability in colorectal cancer}} | |||
==== | =Specific entities= | ||
==Colorectal adenocarcinoma== | |||
*[[AKA]] ''colorectal adenocarcinoma not otherwise specified''. | |||
*[[AKA]] ''colorectal carcinoma'', abbreviated ''CRC''. | |||
{{Main|Colorectal adenocarcinoma}} | |||
== | ==Secondary colorectal cancer== | ||
===General=== | |||
* | *Uncommon. | ||
*May be suspected. | |||
===Microscopic=== | ===Microscopic=== | ||
Features: | Features: | ||
* | *Normal colorectal mucosa. | ||
*Atypical cells in the lamina propria or submucosa. | |||
* | DDx: | ||
*Colorectal neuroendocrine tumour. | |||
=== | ===Images=== | ||
<gallery> | |||
Image:Prostate carcinoma in rectum -- very low mag.jpg | Pca in rectum - very low mag. (WC) | |||
Image:Prostate carcinoma in rectum -- low mag.jpg | Pca in rectum - low mag. (WC) | |||
Image:Prostate carcinoma in rectum -- intermed mag.jpg | Pca in rectum - intermed. mag. (WC) | |||
Image:Prostate carcinoma in rectum -- high mag.jpg | Pca in rectum - high mag. (WC) | |||
</gallery> | |||
<gallery> | |||
Image:Prostate carcinoma in rectum - PSAP -- intermed mag.jpg | Pca in rectum - PSAP - intermed. mag. (WC) | |||
Image:Prostate carcinoma in rectum - PSA -- intermed mag.jpg | Pca in rectum - PSA - intermed. mag. (WC) | |||
Image:Prostate carcinoma in rectum - CK20 -- intermed mag.jpg | Pca in rectum - CK20 - intermed. mag. (WC) | |||
</gallery> | |||
=See also= | |||
*[[Anus]] - covers anal cancer and anal intraepithelial neoplasia. | |||
*[[Colon]]. | *[[Colon]]. | ||
*[[Gastrointestinal pathology]]. | *[[Gastrointestinal pathology]]. | ||
*[[Tumour budding]]. | |||
*[[Tumour perforation in colorectal cancer]]. | |||
*[[Transanal minimally invasive surgery]]. | |||
=References= | |||
{{reflist|2}} | {{reflist|2}} | ||
[[Category:Gastrointestinal pathology]] | [[Category:Gastrointestinal pathology]] |
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