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WHO Classification of Tumours
Adenocarcinoma, NOS
Anus and anal canal


Definition

A common, malignant tumour characterized by the presence of malignant glandular cells. Morphologically, adenocarcinomas are classified according to the growth pattern (e.g., papillary, alveolar) or according to the secreted product (e.g., mucinous, serous). Representative examples of adenocarcinoma are ductal and lobular breast carcinoma, lung adenocarcinoma, renal cell adenocarcinoma, hepatocellular carcinoma, colon adenocarcinoma, and prostate adenocarcinoma.

Adenocarcinoma of the anal canal
This is an adenocarcinoma arising in the epithelium of the anal canal, including the mucosal surface, extramucosal (perianal], the anal glands and the lining of fistulous tracts.

Adenocarcinoma arising in anal mucosa
Most adenocarcinomas found in the anal canal represent downward spread from an adenocarcinoma in the rectum or arise in colorectal-type mucosa above the dentate line. Macroscopically and histologically, they are indistinguishable from ordinary colorectal-type adenocarcinoma, and do not seem to represent a special entity, except for their low location. Adenocarcinoma in the anal transitional zone may develop after restorative proctocolectomy for ulcerative colitis

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Sequens R (1997)
Cancer in the anal canal (transitional zone) after restorative proctocolectomy with stapled ileal pouch-anal anastomosis.
Int J Colorectal Dis 12: 254-5



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Extramucosal (perianal) adenocarcinoma
Approximately 200 cases of extramucosal adenocarcinoma have been reported, the largest series unfortunately with insufficient histological data [[5]]. A minimum criterion for diagnosis is an overlying nonneoplastic mucosa, which may be ulcerated. Recent reports indicate that about two thirds of these tumours manifest in men with a mean age of about 60 years. Reliable data for the prognosis for such patients have not been identified. Difficulties in establishing the correct diagnosis may delay proper treatment. Extramucosal adenocarcinomas seem to fall into two groups on the basis of their association with either fistulae or remnants of anal glands. At present, no laboratory methods can distinguish between these two groups. The epithelium of persistent anal fistulae is most often of the same type as that found in the anal glands and anal transitional zone

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Lunniss PJ, Sheffield JP, Talbot IC, Thomson JP, Phillips RK (1995)
Persistence of idiopathic anal fistula may be related to epithelialization.
Br J Surg 82: 32-3



, and the epithelia in these two locations show the same profile with regard to mucin composition
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Fenger C, Filipe MI (1981)
Mucin histochemistry of the anal canal epithelium. Studies of normal anal mucosa and mucosa adjacent to carcinoma.
Histochem J 13: 921-30



and keratin expression
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Hobbs CM, Lowry MA, Owen D, Sobin LH (2001)
Anal gland carcinoma.
Cancer 92: 2045-9




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Williams GR, Talbot IC, Leigh IM (1997)
Keratin expression in anal carcinoma: an immunohistochemical study.
Histopathology 30: 443-50



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Adenocarcinoma within anorectal fistulae
These tumours develop in pre-existing anal sinuses or in fistulae

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Anthony T, Simmang C, Lee EL, Turnage RH (1997)
Perianal mucinous adenocarcinoma.
J Surg Oncol 64: 218-21



. Some are associated with Crohn disease
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Devon KM, Brown CJ, Burnstein M, McLeod RS (2009)
Cancer of the anus complicating perianal Crohn's disease.
Dis Colon Rectum 52: 211-6




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Ky A, Sohn N, Weinstein MA, Korelitz BI (1998)
Carcinoma arising in anorectal fistulas of Crohn's disease.
Dis Colon Rectum 41: 992-6



. Others may contain epithelioid granulomas, often related to foci of inflammation or extravasated mucin, but without other signs of inflammatory bowel disease
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Jones EA, Morson BC (1984)
Mucinous adenocarcinoma in anorectal fistulae.
Histopathology 8: 279-92



. Rarely, the tumours may be related to fistulae lined by normal rectal mucosa, including muscularis mucosae, most likely representing adenocarcinomas arising in congenital duplications
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Jones EA, Morson BC (1984)
Mucinous adenocarcinoma in anorectal fistulae.
Histopathology 8: 279-92



. Histologically, carcinomas arising in fistulae usually are of the mucinous type, but tubular adenocarcinomas and squamous neoplasia can also be found
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Ky A, Sohn N, Weinstein MA, Korelitz BI (1998)
Carcinoma arising in anorectal fistulas of Crohn's disease.
Dis Colon Rectum 41: 992-6




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Yeong ML, Wood KP, Scott B, Yun K (1992)
Synchronous squamous and glandular neoplasia of the anal canal.
J Clin Pathol 45: 261-3



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Adenocarcinoma of anal glands
Only a few cases have been reported in which convincing evidence for origin in an anal gland has been demonstrated by continuity between anal-gland epithelium and tumour

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Basik M, Rodriguez-Bigas MA, Penetrante R, Petrelli NJ (1995)
Prognosis and recurrence patterns of anal adenocarcinoma.
Am J Surg 169: 233-7




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Hagihara P, Vazquez MD, Parker JC, Griffen WO (1976)
Carcinoma of anal-ductal origin: report of a case.
Dis Colon Rectum 19: 694-701




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Parks TG (1970)
Mucus-secreting adenocarcinoma of anal gland origin.
Br J Surg 57: 434-6




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WELLMAN KF (1962)
Adenocarcinoma of anal duct origin.
Can J Surg 5: 311-8




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Wong AY, Rahilly MA, Adams W, Lee CS (1998)
Mucinous anal gland carcinoma with perianal Pagetoid spread.
Pathology 30: 1-3



. With a single exception
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Hagihara P, Vazquez MD, Parker JC, Griffen WO (1976)
Carcinoma of anal-ductal origin: report of a case.
Dis Colon Rectum 19: 694-701



, these patients have had no history of previous or concomitant fistula. The tumours were all characterized by a ductular architecture with scant production of mucin. Pagetoid spread was present in at least one case
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Wong AY, Rahilly MA, Adams W, Lee CS (1998)
Mucinous anal gland carcinoma with perianal Pagetoid spread.
Pathology 30: 1-3



. Carcinomas of the anal gland express keratin 7 as well as keratin 5/6 and show a loss of p63 expression, which may be helpful in diagnosis
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Hobbs CM, Lowry MA, Owen D, Sobin LH (2001)
Anal gland carcinoma.
Cancer 92: 2045-9




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Lisovsky M, Patel K, Cymes K, Chase D, Bhuiya T, Morgenstern N (2007)
Immunophenotypic characterization of anal gland carcinoma: loss of p63 and cytokeratin 5/6.
Arch Pathol Lab Med 131: 1304-11



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Anal adenocarcinomas without predisposing conditions as described above are rare. They can arise from adenomas [[584A]], which can be graded as for the colorectum.

The prognosis for anal adenocarcinoma seems to be related only to stage at diagnosis and is poorer than that for SCC

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Basik M, Rodriguez-Bigas MA, Penetrante R, Petrelli NJ (1995)
Prognosis and recurrence patterns of anal adenocarcinoma.
Am J Surg 169: 233-7




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Chang GJ, Gonzalez RJ, Skibber JM, Eng C, Das P, Rodriguez-Bigas MA (2009)
A twenty-year experience with adenocarcinoma of the anal canal.
Dis Colon Rectum 52: 1375-80




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Chen YW, Yen SH, Chen SY, Huang PI, Shiau CY, Liu YM, Lin JK, Wang LW (2007)
Anus-preservation treatment for anal cancer: retrospective analysis at a single institution.
J Surg Oncol 96: 374-80




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Klas JV, Rothenberger DA, Wong WD, Madoff RD (1999)
Malignant tumors of the anal canal: the spectrum of disease, treatment, and outcomes.
Cancer 85: 1686-93




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Myerson RJ, Karnell LH, Menck HR (1997)
The National Cancer Data Base report on carcinoma of the anus.
Cancer 80: 805-15




Click for details
Bosman FT, Carneiro F, Hruban RH, Theise ND (Eds.)
WHO Classification of Tumours of the Digestive System.
4th Edition
International Agency for Research on Cancer: Lyon 2010



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Topographic definition of the anal canal, anal margin and perianal region