Difference between revisions of "Anus"

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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).
=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=
=Benign disease=
==Anal wart==
*See ''[[condyloma acuminatum]]''.
==Pilonidal cyst==
:Also ''pilonidal sinus'' and ''pilonidal disease''.
{{Main|Pilonidal cyst}}
==Perianal abscess==
==Perianal abscess==
===General===
===General===
*Common.
*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===
===Microscopic===
Features:
Features:
*Abscess - (extravascular) cluster of neutrophils - '''key feature'''.
*Abscess - (extravascular) cluster of neutrophils - '''key feature'''.
*Reactive epithelium.
*+/-Skin ulceration with reactive epithelium.
*Reactive stromal cells.
*+/-Reactive stromal cells.
 
DDx:
*[[Squamous cell carcinoma]].
*[[Metastatic]] [[adenocarcinoma]].


===Sign out===
===Sign out===
<pre>
<pre>
PERIANAL MASS, EXCISION:  
PERIANAL TISSUE ("ABSCESS"), EXCISION:
- PERIANAL ABSCESS.  
- PERIANAL ABSCESS.
- REACTIVE SQUAMOUS EPITHELIUM WITH PARAKERTOSIS AND ULCERATION.  
- REACTIVE SQUAMOUS EPITHELIUM WITH PARAKERTOSIS AND ULCERATION.
- ABUNDANT COCCI ORGANISMS IN CLUSTERS.  
- ABUNDANT COCCI ORGANISMS IN CLUSTERS.
- NEGATIVE FOR MALIGNANCY.
</pre>
 
<pre>
PERIANAL TISSUE ("ABSCESS"), EXCISION:
- ABSCESS.
- SKIN WITH ULCERATION AND REACTIVE CHANGES.
- NEGATIVE FOR MALIGNANCY.
- NEGATIVE FOR MALIGNANCY.
</pre>
</pre>


==Hidradenoma papilliferum==
====Micro====
:See ''[[Hidradenoma papilliferum]]''.
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.


==Hemorrhoids==
==Anal fistula==
===General===
===General===
*Benign.
*[[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>


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>
===Microscopic===
*Bright red blood per rectum (BRBPR).
Features:
*Pain.
*Squamous mucosa with acute and chronic inflammation.
*Itching.
*Prolapse.


===Gross===
DDx:
Features:<ref name=Ref_GLP401>{{Ref GLP|401}}</ref>
*[[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>
*Grey mucosa.
 
*Pale or purple stroma.
===Sign out===
<pre>
Submitted as "Perineal Fistula Tract", Excision:
    - Consistent with fistula tract (acutely and chronically inflamed
      squamous mucosa with subepithelial inflamed tract, skeletal muscle
      and fibrosed tissue).
    - NEGATIVE for dysplasia and NEGATIVE for malignancy.
</pre>


===Microscopic===
====Block letters====
Features:<ref name=Ref_GLP401>{{Ref GLP|401}}</ref>
<pre>
*Polypoid lesion - epithelium on three sides:
PERIANAL TISSUE ("OPENING OF FISTULA"), EXCISION:
**Large dilated veins and thick-walled vessels +/- fibrin thrombi - '''key feature'''.
- PERIANAL TISSUE CONSISTING OF SCANT SQUAMOUS EPITHELIUM AND MUSCLE
**Edema.
  WITH MILD INFLAMMATION.
**Squamous epithelium +/- keratinization ''or'' columnar epithelium.
- SMALL COLLECTION OF NEUTROPHILS.
- MILD FIBROSIS WITH FOCALLY PROMINENT DILATED BLOOD VESSELS.
- NEGATIVE FOR DYSPLASIA AND NEGATIVE FOR MALIGNANCY.
</pre>


DDx:
==Hidradenoma papilliferum==
*[[Fibroepithelial polyp]].
:See ''[[Hidradenoma papilliferum]]''.
*Vascular lesions.
*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>
**[[Kaposi sarcoma]].
**[[Angiosarcoma]].


Image:
==Hemorrhoids==
*[http://www.profimedia.si/picture/longitudinal-section-of-human-rectum-hemorrhoid-tissue/0039860546/ Hemorrhoids (profimedia.si)].
{{Main|Hemorrhoid}}


=Anal neoplasia=
=Anal neoplasia=
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==Anal intraepithelial neoplasia==
==Anal intraepithelial neoplasia==
*Abbreviated ''AIN''.
*Abbreviated ''AIN''.
===General===
{{Main|Anal intraepithelial lesions}}
*Precursor lesion of anal [[squamous cell carcinoma]].
*Usually [[HPV]] associated.
**May be prevented by HPV vaccine.


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


==Anal gland adenocarcinoma==
==Anal gland adenocarcinoma==
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DDx:
DDx:
*[[Rectal adenocarcinoma]] - usu. CK7 -ve, CK20 +ve.
*[[Rectal adenocarcinoma]] - usu. CK7 -ve, CK20 +ve.
*Mucinous adenocarcinoma - usu. CK7 +ve, CK20 +ve.
*[[Mucinous adenocarcinoma]] - usu. CK7 +ve, CK20 +ve.


Image:
Image:
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===IHC===
===IHC===
Features:<ref name=pmid22690260/>
Features:<ref name=pmid22690260/>
*CK7 +ve.  
*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.  
*CK20 -ve.  
*CDX2 -ve.  
*CDX2 -ve.  

Latest revision as of 16:29, 6 April 2022

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

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.[1]

Squamous metaplasia of the anus

Main article: Squamous metaplasia of the anus

Benign disease

Anal wart

Pilonidal cyst

Also pilonidal sinus and pilonidal disease.
Main article: Pilonidal cyst

Perianal abscess

General

Microscopic

Features:

  • Abscess - (extravascular) cluster of neutrophils - key feature.
  • +/-Skin ulceration with reactive epithelium.
  • +/-Reactive stromal cells.

DDx:

Sign out

PERIANAL TISSUE ("ABSCESS"), EXCISION:
- PERIANAL ABSCESS.
- REACTIVE SQUAMOUS EPITHELIUM WITH PARAKERTOSIS AND ULCERATION.
- ABUNDANT COCCI ORGANISMS IN CLUSTERS.
- NEGATIVE FOR MALIGNANCY.

PERIANAL TISSUE ("ABSCESS"), EXCISION:
- ABSCESS.
- SKIN WITH ULCERATION AND REACTIVE CHANGES.
- NEGATIVE FOR MALIGNANCY.

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

Microscopic

Features:

  • Squamous mucosa with acute and chronic inflammation.

DDx:

Sign out

Submitted as "Perineal Fistula Tract", Excision:
     - Consistent with fistula tract (acutely and chronically inflamed 
       squamous mucosa with subepithelial inflamed tract, skeletal muscle 
       and fibrosed tissue).
     - NEGATIVE for dysplasia and NEGATIVE for malignancy.

Block letters

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.

Hidradenoma papilliferum

See Hidradenoma papilliferum.
  • Can be perianal.[6]

Hemorrhoids

Main article: Hemorrhoid

Anal neoplasia

Immunosuppressed individuals and homosexuals have a higher risk of anal intraepithelial neoplasia (AIN) and anal cancer.[7][8]

Anal intraepithelial neoplasia

  • Abbreviated AIN.
Main article: Anal intraepithelial lesions

Note:

  • The terminology changing to match the one now widely used for the uterine cervix.

Anal cancer

Anal squamous cell carcinoma

  • AKA anal squamous carcinoma.
  • AKA squamous cell carcinoma of the anus.
Main article: Anal squamous cell carcinoma

Anal gland adenocarcinoma

  • Abbreviation AGA.
  • AKA anal adenocarcinoma.

General

  • Rare.

Risk factors:[9]

Microscopic

Features:[10]

  • Adenocarcinoma within the anal wall but not within the mucosa, i.e. extramucosal and intramural - key feature.
    • The tumour lies beneath the squamous mucosa/rectal mucosa.

DDx:

Image:

IHC

Features:[10]

  • CK7 +ve (5 of 5[11]).
  • p16 -ve (5 of 5[11]).
  • CK20 -ve.
  • CDX2 -ve.
  • p63 -ve.
  • PSA -ve.

See also

References

  1. ↑ Bujanda, L.; Iriondo, C.; Muñoz, C.; Etxezarraga, C.; Ramírez, MM.; Ramos, F.; Sánchez, A. (Feb 2001). "Squamous metaplasia of the rectum and sigmoid colon.". Gastrointest Endosc 53 (2): 255-6. PMID 11174313.
  2. ↑ Ommer, A.; Herold, A.; Berg, E.; Fürst, A.; Sailer, M.; Schiedeck, T. (Jun 2012). "German S3 guideline: anal abscess.". Int J Colorectal Dis 27 (6): 831-7. doi:10.1007/s00384-012-1430-x. PMID 22362468.
  3. ↑ Lewis, RT.; Maron, DJ. (Sep 2010). "Efficacy and complications of surgery for Crohn's disease.". Gastroenterol Hepatol (N Y) 6 (9): 587-96. PMID 21088749.
  4. ↑ Burri, E.; Vavricka, SR. (Jul 2013). "[Perianal Crohn's disease].". Ther Umsch 70 (7): 417-28. doi:10.1024/0040-5930/a000427. PMID 23798025.
  5. ↑ Benjelloun, el B.; Abkari, M.; Ousadden, A.; Ait Taleb, K. (Jul 2013). "Squamous cell carcinoma associated anal fistulas in Crohn's disease unique case report with literature review.". J Crohns Colitis 7 (6): e232-5. doi:10.1016/j.crohns.2012.09.015. PMID 23069004.
  6. ↑ Daniel, F.; Mahmoudi, A.; de Parades, V.; Fléjou, JF.; Atienza, P. (Feb 2007). "An uncommon perianal nodule: hidradenoma papilliferum.". Gastroenterol Clin Biol 31 (2): 166-8. PMID 17347625.
  7. ↑ Park IU, Palefsky JM (March 2010). "Evaluation and Management of Anal Intraepithelial Neoplasia in HIV-Negative and HIV-Positive Men Who Have Sex with Men". Curr Infect Dis Rep 12 (2): 126–133. doi:10.1007/s11908-010-0090-7. PMC 2860554. PMID 20461117. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2860554/.
  8. ↑ Czoski-Murray C, Karnon J, Jones R, Smith K, Kinghorn G (November 2010). "Cost-effectiveness of screening high-risk HIV-positive men who have sex with men (MSM) and HIV-positive women for anal cancer". Health Technol Assess 14 (53): 1–131. doi:10.3310/hta14530. PMID 21083999.
  9. ↑ Tarazi, R.; Nelson, RL.. "Anal adenocarcinoma: a comprehensive review.". Semin Surg Oncol 10 (3): 235-40. PMID 8085101.
  10. ↑ 10.0 10.1 10.2 Warsch, S.; Bayraktar, UD.; Wen, BC.; Zeitouni, J.; Marchetti, F.; Rocha-Lima, CM.; Montero, AJ. (Mar 2012). "Successful treatment of anal gland adenocarcinoma with combined modality therapy.". Gastrointest Cancer Res 5 (2): 64-6. PMID 22690260.
  11. ↑ 11.0 11.1 Meriden, Z.; Montgomery, EA. (Feb 2012). "Anal duct carcinoma: a report of 5 cases.". Hum Pathol 43 (2): 216-20. doi:10.1016/j.humpath.2011.04.019. PMID 21820151.
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