Difference between revisions of "Anus"

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Anus (view source)

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The '''anus''' occasionally shows-up on the pathologists desk.  It sometimes comes with the rectum and [[colon]], as an abdominoperoneal resection (APR).
The '''anus''' occasionally shows-up on the pathologists desk.  It sometimes comes with the rectum and [[colon]], as an abdominoperoneal resection (APR).


==Anal neoplasia==
=Normal=
*The dentate line (also known as the ''pectinate line'') divides the anal canal into upper two thirds and lower one third.
*Typically, the squamocolumnar junction is just above the dentate line.
 
Note:
*Squamous epithelium 1 cm proximal to the dentate line is considered abnormal.<ref name=pmid11174313>{{Cite journal  | last1 = Bujanda | first1 = L. | last2 = Iriondo | first2 = C. | last3 = Muñoz | first3 = C. | last4 = Etxezarraga | first4 = C. | last5 = Ramírez | first5 = MM. | last6 = Ramos | first6 = F. | last7 = Sánchez | first7 = A. | title = Squamous metaplasia of the rectum and sigmoid colon. | journal = Gastrointest Endosc | volume = 53 | issue = 2 | pages = 255-6 | month = Feb | year = 2001 | doi =  | PMID = 11174313 }}</ref>
 
==Squamous metaplasia of the anus==
{{Main|Squamous metaplasia of the anus}}
 
=Benign disease=
==Anal wart==
*See ''[[condyloma acuminatum]]''.
 
==Pilonidal cyst==
:Also ''pilonidal sinus'' and ''pilonidal disease''.
{{Main|Pilonidal cyst}}
 
==Perianal abscess==
===General===
*Common [[ditzel]] - often young men.<ref name=pmid22362468>{{Cite journal  | last1 = Ommer | first1 = A. | last2 = Herold | first2 = A. | last3 = Berg | first3 = E. | last4 = Fürst | first4 = A. | last5 = Sailer | first5 = M. | last6 = Schiedeck | first6 = T. | title = German S3 guideline: anal abscess. | journal = Int J Colorectal Dis | volume = 27 | issue = 6 | pages = 831-7 | month = Jun | year = 2012 | doi = 10.1007/s00384-012-1430-x | PMID = 22362468 }}</ref>
*May be due to [[Crohn's disease]].<ref name=pmid21088749>{{Cite journal  | last1 = Lewis | first1 = RT. | last2 = Maron | first2 = DJ. | title = Efficacy and complications of surgery for Crohn's disease. | journal = Gastroenterol Hepatol (N Y) | volume = 6 | issue = 9 | pages = 587-96 | month = Sep | year = 2010 | doi =  | PMID = 21088749 }}</ref>
 
===Microscopic===
Features:
*Abscess - (extravascular) cluster of neutrophils - '''key feature'''.
*+/-Skin ulceration with reactive epithelium.
*+/-Reactive stromal cells.
 
DDx:
*[[Squamous cell carcinoma]].
*[[Metastatic]] [[adenocarcinoma]].
 
===Sign out===
<pre>
PERIANAL TISSUE ("ABSCESS"), EXCISION:
- PERIANAL ABSCESS.
- REACTIVE SQUAMOUS EPITHELIUM WITH PARAKERTOSIS AND ULCERATION.
- ABUNDANT COCCI ORGANISMS IN CLUSTERS.
- NEGATIVE FOR MALIGNANCY.
</pre>
 
<pre>
PERIANAL TISSUE ("ABSCESS"), EXCISION:
- ABSCESS.
- SKIN WITH ULCERATION AND REACTIVE CHANGES.
- NEGATIVE FOR MALIGNANCY.
</pre>
 
====Micro====
The sections show skin with acanthosis, hypergranulosis, compact hyperkeratosis and focal full thickness loss of the epidermis, associated with a mixed inflammatory infiltrate. The dermis has reactive fibroblasts with moderate grey cytoplasm, nuclear enlargement and round small nucleoli. The fibroblast nuclei have regular nuclear membranes and a bland chromatin pattern. Clusters of neutrophils are present. There is no epidermal nuclear atypia. Mitotic activity is seen focally. No atypical mitotic figures are apparent. The inflammation extends to the deep aspect of the specimen.
 
==Anal fistula==
===General===
*[[Clinical diagnosis]].
*May be seen in association with an [[perianal abscess|abscess]].
*Common in Crohn's disease.<ref name=pmid23798025>{{Cite journal  | last1 = Burri | first1 = E. | last2 = Vavricka | first2 = SR. | title = [Perianal Crohn's disease]. | journal = Ther Umsch | volume = 70 | issue = 7 | pages = 417-28 | month = Jul | year = 2013 | doi = 10.1024/0040-5930/a000427 | PMID = 23798025 }}</ref>
 
===Microscopic===
Features:
*Squamous mucosa with acute and chronic inflammation.
 
DDx:
*[[Squamous cell carcinoma]].<ref name=pmid23069004>{{Cite journal  | last1 = Benjelloun | first1 = el B. | last2 = Abkari | first2 = M. | last3 = Ousadden | first3 = A. | last4 = Ait Taleb | first4 = K. | title = Squamous cell carcinoma associated anal fistulas in Crohn's disease unique case report with literature review. | journal = J Crohns Colitis | volume = 7 | issue = 6 | pages = e232-5 | month = Jul | year = 2013 | doi = 10.1016/j.crohns.2012.09.015 | PMID = 23069004 }}</ref>
 
===Sign out===
<pre>
PERIANAL TISSUE ("OPENING OF FISTULA"), EXCISION:
- PERIANAL TISSUE CONSISTING OF SCANT SQUAMOUS EPITHELIUM AND MUSCLE
  WITH MILD INFLAMMATION.
- SMALL COLLECTION OF NEUTROPHILS.
- MILD FIBROSIS WITH FOCALLY PROMINENT DILATED BLOOD VESSELS.
- NEGATIVE FOR DYSPLASIA AND NEGATIVE FOR MALIGNANCY.
</pre>
 
==Hidradenoma papilliferum==
:See ''[[Hidradenoma papilliferum]]''.
*Can be perianal.<ref name=pmid17347625>{{Cite journal  | last1 = Daniel | first1 = F. | last2 = Mahmoudi | first2 = A. | last3 = de Parades | first3 = V. | last4 = Fléjou | first4 = JF. | last5 = Atienza | first5 = P. | title = An uncommon perianal nodule: hidradenoma papilliferum. | journal = Gastroenterol Clin Biol | volume = 31 | issue = 2 | pages = 166-8 | month = Feb | year = 2007 | doi =  | PMID = 17347625 }}</ref>
 
==Hemorrhoids==
{{Main|Hemorrhoid}}
 
=Anal neoplasia=
Immunosuppressed individuals and homosexuals have a higher risk of anal intraepithelial neoplasia (AIN) and anal cancer.<ref name=pmid20461117>{{cite journal |author=Park IU, Palefsky JM |title=Evaluation and Management of Anal Intraepithelial Neoplasia in HIV-Negative and HIV-Positive Men Who Have Sex with Men |journal=Curr Infect Dis Rep |volume=12 |issue=2 |pages=126–133 |year=2010 |month=March |pmid=20461117 |pmc=2860554 |doi=10.1007/s11908-010-0090-7 |url=}}</ref><ref name=pmid21083999>{{cite journal |author=Czoski-Murray C, Karnon J, Jones R, Smith K, Kinghorn G |title=Cost-effectiveness of screening high-risk HIV-positive men who have sex with men (MSM) and HIV-positive women for anal cancer |journal=Health Technol Assess |volume=14 |issue=53 |pages=1–131 |year=2010 |month=November |pmid=21083999 |doi=10.3310/hta14530 |url=}}</ref>  
Immunosuppressed individuals and homosexuals have a higher risk of anal intraepithelial neoplasia (AIN) and anal cancer.<ref name=pmid20461117>{{cite journal |author=Park IU, Palefsky JM |title=Evaluation and Management of Anal Intraepithelial Neoplasia in HIV-Negative and HIV-Positive Men Who Have Sex with Men |journal=Curr Infect Dis Rep |volume=12 |issue=2 |pages=126–133 |year=2010 |month=March |pmid=20461117 |pmc=2860554 |doi=10.1007/s11908-010-0090-7 |url=}}</ref><ref name=pmid21083999>{{cite journal |author=Czoski-Murray C, Karnon J, Jones R, Smith K, Kinghorn G |title=Cost-effectiveness of screening high-risk HIV-positive men who have sex with men (MSM) and HIV-positive women for anal cancer |journal=Health Technol Assess |volume=14 |issue=53 |pages=1–131 |year=2010 |month=November |pmid=21083999 |doi=10.3310/hta14530 |url=}}</ref>  


==Anal intraepithelial neoplasia==
==Anal intraepithelial neoplasia==
*Abbreviated ''AIN''.
*Abbreviated ''AIN''.
===General===
{{Main|Anal intraepithelial lesions}}
*Precursor lesion of anal cancer.
*Usually [[HPV]] associated.


===Grading===
Note:
AIN is graded much like [[cervix|cervical intraepithelial neoplasia]]:
*The terminology changing to match the one now widely used for the [[uterine cervix]].
*High-grade anal intraepithelial neoplasia (HGAIN).
*Low-grade anal intraepithelial neoplasia (LGAIN).


==Anal cancer==
=Anal cancer=
*[[Squamous cell carcinoma]] - most common.
*[[Anal squamous cell carcinoma]] - may be referred to as ''anal carcinoma'' - most common.
*[[Malignant melanoma]].
*[[Malignant melanoma]].
*[[Adenocarcinoma]] from the [[rectum]].
*[[Adenocarcinoma]] from the [[rectum]].


==Hidradenoma papilliferum==
==Anal squamous cell carcinoma==
:See ''[[Hidradenoma papilliferum]]''.
*[[AKA]] ''anal squamous carcinoma''.
*[[AKA]] ''squamous cell carcinoma of the anus''.
{{Main|Anal squamous cell carcinoma}}


==Hemorrhoids==
==Anal gland adenocarcinoma==
*Abbreviation ''AGA''.
*[[AKA]] ''anal adenocarcinoma''.
===General===
===General===
*Benign.
*Rare.


Clinical features:<ref>{{Cite journal  | last1 = Cazemier | first1 = M. | last2 = Felt-Bersma | first2 = RJ. | last3 = Cuesta | first3 = MA. | last4 = Mulder | first4 = CJ. | title = Elastic band ligation of hemorrhoids: flexible gastroscope or rigid proctoscope? | journal = World J Gastroenterol | volume = 13 | issue = 4 | pages = 585-7 | month = Jan | year = 2007 | doi =  | PMID = 17278225 }}</ref>
Risk factors:<ref name=pmid8085101>{{Cite journal  | last1 = Tarazi | first1 = R. | last2 = Nelson | first2 = RL. | title = Anal adenocarcinoma: a comprehensive review. | journal = Semin Surg Oncol | volume = 10 | issue = 3 | pages = 235-40 | month = | year = | doi =  | PMID = 8085101 }}</ref>
*Bright red blood per rectum (BRBPR).
*Anal [[Crohn's disease]].
*Pain.
*Chronic anal fistula.
*Itching.
*Anal sexual intercourse.
*Prolapse.


===Microscopic===
===Microscopic===
Features:
Features:<ref name=pmid22690260/>
*Polypoid lesion:
*Adenocarcinoma within the anal wall but not within the mucosa, i.e. extramucosal and intramural - '''key feature'''.
**Large dilated veins +/- fibrin thrombi.
**The tumour lies beneath the squamous mucosa/rectal mucosa.
**Fibrotic stroma.
 
**Squamous epithelium +/- keratinization.
DDx:
*[[Rectal adenocarcinoma]] - usu. CK7 -ve, CK20 +ve.
*[[Mucinous adenocarcinoma]] - usu. CK7 +ve, CK20 +ve.
 
Image:
*[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3369602/figure/F1/ Anal adenocarcinoma (nih.gov)].<ref name=pmid22690260>{{Cite journal  | last1 = Warsch | first1 = S. | last2 = Bayraktar | first2 = UD. | last3 = Wen | first3 = BC. | last4 = Zeitouni | first4 = J. | last5 = Marchetti | first5 = F. | last6 = Rocha-Lima | first6 = CM. | last7 = Montero | first7 = AJ. | title = Successful treatment of anal gland adenocarcinoma with combined modality therapy. | journal = Gastrointest Cancer Res | volume = 5 | issue = 2 | pages = 64-6 | month = Mar | year = 2012 | doi =  | PMID = 22690260 }}</ref>
 
===IHC===
Features:<ref name=pmid22690260/>
*CK7 +ve (5 of 5<ref name=pmid21820151/>).
*p16 -ve (5 of 5<ref name=pmid21820151>{{Cite journal  | last1 = Meriden | first1 = Z. | last2 = Montgomery | first2 = EA. | title = Anal duct carcinoma: a report of 5 cases. | journal = Hum Pathol | volume = 43 | issue = 2 | pages = 216-20 | month = Feb | year = 2012 | doi = 10.1016/j.humpath.2011.04.019 | PMID = 21820151 }}</ref>).
*CK20 -ve.
*CDX2 -ve.  
*p63 -ve.
*PSA -ve.


==See also==
=See also=
*[[Colon]].
*[[Colon]].
*[[Dermatopathology]].
*[[Dermatopathology]].


==References==
=References=
{{Reflist|1}}
{{Reflist|2}}


[[Category:Gastrointestinal pathology]]
[[Category:Gastrointestinal pathology]]
Michael
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