Squamous metaplasia of the rectum/anus - Revision history

Michael: /* General */

2016-06-16T02:42:53Z

General

← Older revision		Revision as of 02:42, 16 June 2016
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	*Present in the transformation zone between the columnar epithelium of the [[rectum]] and squamous epithelium of the [[anus]] - similar to the transformation zone of the [[uterine cervix]].<ref name=pmid20436833>{{Cite journal \| last1 = Pineda \| first1 = CE. \| last2 = Welton \| first2 = ML. \| title = Management of anal squamous intraepithelial lesions. \| journal = Clin Colon Rectal Surg \| volume = 22 \| issue = 2 \| pages = 94-101 \| month = May \| year = 2009 \| doi = 10.1055/s-0029-1223840 \| PMID = 20436833 }}</ref>		*Present in the transformation zone between the columnar epithelium of the [[rectum]] and squamous epithelium of the [[anus]] - similar to the transformation zone of the [[uterine cervix]].<ref name=pmid20436833>{{Cite journal \| last1 = Pineda \| first1 = CE. \| last2 = Welton \| first2 = ML. \| title = Management of anal squamous intraepithelial lesions. \| journal = Clin Colon Rectal Surg \| volume = 22 \| issue = 2 \| pages = 94-101 \| month = May \| year = 2009 \| doi = 10.1055/s-0029-1223840 \| PMID = 20436833 }}</ref>

	~~Anatomy & histology~~:		Note:
	*~~Typically,~~ the ~~squamocolumnar junction is just above~~ the ~~dentate line (also~~ ''~~pectinate line~~'').		*The anatomy & histology of the anus covered in the ''[[anus]]'' article.
	*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>
	*The dentate line divides the anal canal into upper two thirds and lower third.

	==Microscopic==		==Microscopic==

Michael: /* General */

2016-06-16T02:41:46Z

General

← Older revision		Revision as of 02:41, 16 June 2016
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	==General==		==General==
	*Present in the transformation zone between the columnar epithelium of the [[rectum]] and squamous epithelium of the [[anus]] - similar to the transformation zone of the [[uterine cervix]].<ref name=pmid20436833>{{Cite journal \| last1 = Pineda \| first1 = CE. \| last2 = Welton \| first2 = ML. \| title = Management of anal squamous intraepithelial lesions. \| journal = Clin Colon Rectal Surg \| volume = 22 \| issue = 2 \| pages = 94-101 \| month = May \| year = 2009 \| doi = 10.1055/s-0029-1223840 \| PMID = 20436833 }}</ref>		*Present in the transformation zone between the columnar epithelium of the [[rectum]] and squamous epithelium of the [[anus]] - similar to the transformation zone of the [[uterine cervix]].<ref name=pmid20436833>{{Cite journal \| last1 = Pineda \| first1 = CE. \| last2 = Welton \| first2 = ML. \| title = Management of anal squamous intraepithelial lesions. \| journal = Clin Colon Rectal Surg \| volume = 22 \| issue = 2 \| pages = 94-101 \| month = May \| year = 2009 \| doi = 10.1055/s-0029-1223840 \| PMID = 20436833 }}</ref>

			Anatomy & histology:
			*Typically, the squamocolumnar junction is just above the dentate line (also ''pectinate line'').
			*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>
			*The dentate line divides the anal canal into upper two thirds and lower third.

	==Microscopic==		==Microscopic==

Michael at 02:34, 16 June 2016

2016-06-16T02:34:48Z

← Older revision		Revision as of 02:34, 16 June 2016
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	'''Squamous metaplasia of the rectum''' is a metaplastic change of the columnar epithelium of the rectum.		'''Squamous metaplasia of the rectum/anus''' is a metaplastic change of the columnar epithelium of the rectum.

	It can histologically mimic [[anal intraepithelial neoplasia]] (AIN), especially. [[high-grade squamous intraepithelial lesion]] (HSIL).		It can histologically mimic [[anal intraepithelial neoplasia]] (AIN), especially. [[high-grade squamous intraepithelial lesion]] (HSIL).

Michael: Michael moved page Squamous metaplasia of the rectum to Squamous metaplasia of the rectum/anus

2016-06-16T02:34:32Z

Michael moved page Squamous metaplasia of the rectum to Squamous metaplasia of the rectum/anus

← Older revision	Revision as of 02:34, 16 June 2016
(No difference)

Michael: /* See also */

2016-06-16T02:22:03Z

Michael at 02:21, 16 June 2016

2016-06-16T02:21:34Z

← Older revision		Revision as of 02:21, 16 June 2016
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	'''Squamous metaplasia of the ~~anus~~''' is a metaplastic change of the columnar epithelium. It can histologically mimic [[anal intraepithelial neoplasia]] (AIN), especially. [[high-grade squamous intraepithelial lesion]] (HSIL).		'''Squamous metaplasia of the rectum''' is a metaplastic change of the columnar epithelium of the rectum.

			It can histologically mimic [[anal intraepithelial neoplasia]] (AIN), especially. [[high-grade squamous intraepithelial lesion]] (HSIL).

	==General==		==General==

Michael: Michael moved page Squamous metaplasia of the anus to Squamous metaplasia of the rectum

2016-06-16T02:20:48Z

Michael moved page Squamous metaplasia of the anus to Squamous metaplasia of the rectum

← Older revision	Revision as of 02:20, 16 June 2016
(No difference)

Michael at 02:18, 16 June 2016

2016-06-16T02:18:11Z

← Older revision		Revision as of 02:18, 16 June 2016
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	'''Squamous metaplasia of the anus''' is a metaplastic change of the columnar epithelium. It can histologically mimic [[anal intraepithelial neoplasia]] (AIN), especially. [[high-grade squamous intraepithelial lesion]] (HSIL).		'''Squamous metaplasia of the anus''' is a metaplastic change of the columnar epithelium. It can histologically mimic [[anal intraepithelial neoplasia]] (AIN), especially. [[high-grade squamous intraepithelial lesion]] (HSIL).

			==General==
			*Present in the transformation zone between the columnar epithelium of the [[rectum]] and squamous epithelium of the [[anus]] - similar to the transformation zone of the [[uterine cervix]].<ref name=pmid20436833>{{Cite journal \| last1 = Pineda \| first1 = CE. \| last2 = Welton \| first2 = ML. \| title = Management of anal squamous intraepithelial lesions. \| journal = Clin Colon Rectal Surg \| volume = 22 \| issue = 2 \| pages = 94-101 \| month = May \| year = 2009 \| doi = 10.1055/s-0029-1223840 \| PMID = 20436833 }}</ref>

	==Microscopic==		==Microscopic==

Michael at 02:09, 16 June 2016

2016-06-16T02:09:27Z

← Older revision		Revision as of 02:09, 16 June 2016
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	'''Squamous metaplasia of the anus''' is a metaplastic change of the columnar epithelium. It can histologically mimic [[anal intraepithelial neoplasia]] (AIN), especially. [[high-grade squamous intraepithelial lesion]] (HSIL).		'''Squamous metaplasia of the anus''' is a metaplastic change of the columnar epithelium. It can histologically mimic [[anal intraepithelial neoplasia]] (AIN), especially. [[high-grade squamous intraepithelial lesion]] (HSIL).

			==Microscopic==
			Features:
			* Uniform cell spacing - no crowding - '''key feature'''.
			* Nuclei are uniform size and round.
			** +/-[[Nucleoli]] present.
			*Distinct cell borders
			* +/-Intercellular bridges (due to edema) - common.

			Negatives:
			* No mitoses/rare basal mitoses - think cancer/AIN if you see 'em.
			* Usually no hyperchromatism (think cancer/CIN if you see it).

			DDx:
			*[[Anal intraepithelial lesion]].

	===Images===		===Images===

Michael: create

2016-06-16T02:05:25Z

create

New page

'''Squamous metaplasia of the anus''' is a metaplastic change of the columnar epithelium. It can histologically mimic [[anal intraepithelial neoplasia]] (AIN), especially. [[high-grade squamous intraepithelial lesion]] (HSIL).

===Images===
<gallery>
Image: Immature squamous metaplasia - anus -- very low mag.jpg | ISM - very low mag.
Image: Immature squamous metaplasia - anus -- low mag.jpg | ISM - low mag.
Image: Immature squamous metaplasia - anus -- intermed mag.jpg | ISM - intermed. mag.
Image: Immature squamous metaplasia - anus -- high mag.jpg | ISM - high mag.
</gallery>

==IHC==
*p16 -ve
**Usually weak-to-moderate patchy, not full thickness.
*Ki-67 - scattered cells positive.

==See also==
*[[Squamous metaplasia]].

[[Category:Gastrointestinal pathology]]
[[Category:Dermatopathology]]

← Older revision		Revision as of 02:22, 16 June 2016
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	==See also==		==See also==
	*[[Squamous metaplasia]].		*[[Squamous metaplasia]].

			==References==
			{{Reflist\|1}}

	[[Category:Gastrointestinal pathology]]		[[Category:Gastrointestinal pathology]]
	[[Category:Dermatopathology]]		[[Category:Dermatopathology]]