Difference between revisions of "Anus"
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The sections show rectal and anal mucosa, and a submucosa with prominent blood vessels in a fibrotic stroma. The rectal mucosa has focal reactive nuclear changes and evidence of prior erosions. | The sections show rectal and anal mucosa, and a submucosa with prominent blood vessels in a fibrotic stroma. The rectal mucosa has focal reactive nuclear changes and evidence of prior erosions. The anal mucosa is unremarkable. | ||
=Anal neoplasia= | =Anal neoplasia= | ||
Revision as of 07:44, 26 June 2013
The anus occasionally shows-up on the pathologists desk. It sometimes comes with the rectum and colon, as an abdominoperoneal resection (APR).
Benign disease
Anal wart
- See condyloma acuminatum.
Perianal abscess
General
- Common.
Microscopic
Features:
- Abscess - (extravascular) cluster of neutrophils - key feature.
- +/-Skin ulceration with reactive epithelium.
- +/-Reactive stromal cells.
DDx:
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PERIANAL MASS, EXCISION: - PERIANAL ABSCESS. - REACTIVE SQUAMOUS EPITHELIUM WITH PARAKERTOSIS AND ULCERATION. - ABUNDANT COCCI ORGANISMS IN CLUSTERS. - NEGATIVE FOR MALIGNANCY.
Hidradenoma papilliferum
- Can be perianal.[1]
Hemorrhoids
General
- Benign.
Clinical features:[2]
- Bright red blood per rectum (BRBPR).
- Pain.
- Itching.
- Prolapse.
Gross
Features:[3]
- Grey mucosa.
- Pale or purple stroma.
Microscopic
Features:[3]
- Polypoid lesion - epithelium on three sides:
- Large dilated veins and thick-walled vessels +/- fibrin thrombi - key feature.
- Edema.
- Squamous epithelium +/- keratinization or columnar epithelium.
DDx:
- Fibroepithelial polyp.
- Vascular lesions.
Image:
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HEMORRHOIDS, EXCISION: - HEMORRHOIDS.
Micro
The sections show rectal and anal mucosa, and a submucosa with prominent blood vessels in a fibrotic stroma. The rectal mucosa has focal reactive nuclear changes and evidence of prior erosions. The anal mucosa is unremarkable.
Anal neoplasia
Immunosuppressed individuals and homosexuals have a higher risk of anal intraepithelial neoplasia (AIN) and anal cancer.[4][5]
Anal intraepithelial neoplasia
- Abbreviated AIN.
General
- Precursor lesion of anal squamous cell carcinoma.
- Usually HPV associated.
- May be prevented by HPV vaccine.
Grading
AIN is graded much like cervical intraepithelial neoplasia:
- High-grade anal intraepithelial neoplasia (HGAIN).
- Low-grade anal intraepithelial neoplasia (LGAIN).
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SKIN LESION, PERIANAL, BIOPSY: - ANAL INTRAEPITHELIAL NEOPLASIA 3 (SEVERE DYSPLASIA), WARTY-TYPE. - MARGIN POSITIVE FOR ANAL INTRAEPITHELIAL NEOPLASIA 3.
Micro
There is dysplastic squamous epithelium with coarse chromatin, nuclear hyperchromasia, nuclear enlargement, irregular nuclear membranes, and an increase nuclear-to-cytoplasmic ratio. Mitotic activity is abundant. Several atypical mitoses are identified.
The dysplastic squamous epithelium shows minimal maturation toward the surface (AIN 3). A sizable portion of the lesion show some maturation to the surface (AIN 2).
Inflammation at the dermal-epidermal interface is minimal and the dermal-epidermal interface is well-demarcated. Focal ulceration is present.
The margin of the biopsy has severely dysplastic epithelium (AIN 3).
Anal cancer
- Squamous cell carcinoma - most common.
- Malignant melanoma.
- Adenocarcinoma from the rectum.
Anal gland adenocarcinoma
- Abbreviation AGA.
- AKA anal adenocarcinoma.
General
- Rare.
Risk factors:[6]
- Anal Crohn's disease.
- Chronic anal fistula.
- Anal sexual intercourse.
Microscopic
Features:[7]
- 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:
- Rectal adenocarcinoma - usu. CK7 -ve, CK20 +ve.
- Mucinous adenocarcinoma - usu. CK7 +ve, CK20 +ve.
Image:
IHC
Features:[7]
- CK7 +ve.
- CK20 -ve.
- CDX2 -ve.
- p63 -ve.
- PSA -ve.
See also
References
- ↑ 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.
- ↑ Cazemier, M.; Felt-Bersma, RJ.; Cuesta, MA.; Mulder, CJ. (Jan 2007). "Elastic band ligation of hemorrhoids: flexible gastroscope or rigid proctoscope?". World J Gastroenterol 13 (4): 585-7. PMID 17278225.
- ↑ 3.0 3.1 Iacobuzio-Donahue, Christine A.; Montgomery, Elizabeth A. (2005). Gastrointestinal and Liver Pathology: A Volume in the Foundations in Diagnostic Pathology Series (1st ed.). Churchill Livingstone. pp. 401. ISBN 978-0443066573.
- ↑ 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/.
- ↑ 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.
- ↑ Tarazi, R.; Nelson, RL.. "Anal adenocarcinoma: a comprehensive review.". Semin Surg Oncol 10 (3): 235-40. PMID 8085101.
- ↑ 7.0 7.1 7.2 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.