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Difference between revisions of "Pseudomelanosis coli"
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| Width = | | Width = | ||
| Caption = Pseudomelanosis coli. [[H&E stain]]. | | Caption = Pseudomelanosis coli. [[H&E stain]]. | ||
| Synonyms = melanosis coli | |||
| Micro = brown granular pigment in the lamina propria, abundant | | Micro = brown granular pigment in the lamina propria, abundant | ||
| Subtypes = | | Subtypes = | ||
| LMDDx = hemorrhage, [[melanocytic lesion]] (rarely) | | LMDDx = hemorrhage, [[melanocytic lesion]] (rarely) | ||
| Stains = | | Stains = [[PAS stain|PAS]] +ve, [[Prussian blue stain|Prussian blue]] -ve, [[Fontana-Masson stain|Fontana-Masson]] +ve | ||
| IHC = | | IHC = | ||
| EM = | | EM = | ||
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| Gross = | | Gross = | ||
| Grossing = | | Grossing = | ||
| Site = [[colon]], [[cecum]] | | Site = [[colon]], [[cecum]], occasionally [[small intestine]] | ||
| Assdx = | | Assdx = | ||
| Syndromes = | | Syndromes = | ||
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==General== | ==General== | ||
*''Not melanin'' as the name ''melanosis coli'' suggests; it is actually lipofuscin (in macrophages).<ref name=pmid18666316>{{cite journal |author=Freeman HJ |title="Melanosis" in the small and large intestine |journal=World J. Gastroenterol. |volume=14 |issue=27 |pages=4296-9 |year=2008 |month=July |pmid=18666316 |doi= |url=http://www.wjgnet.com/1007-9327/14/4296.asp}}</ref> | *''Not melanin'' as the name ''melanosis coli'' suggests; it is actually [[lipofuscin]] (in macrophages).<ref name=pmid18666316>{{cite journal |author=Freeman HJ |title="Melanosis" in the small and large intestine |journal=World J. Gastroenterol. |volume=14 |issue=27 |pages=4296-9 |year=2008 |month=July |pmid=18666316 |doi= |url=http://www.wjgnet.com/1007-9327/14/4296.asp}}</ref> | ||
*Endoscopist may see brown pigmentation of mucosa and suspect the diagnosis. | *Endoscopist may see brown pigmentation of mucosa and suspect the diagnosis. | ||
*Presence may lead to endoscopic misinterpretation of colitis severity.<ref name=pmid21375218>{{Cite journal | last1 = Zapatier | first1 = JA. | last2 = Schneider | first2 = A. | last3 = Parra | first3 = JL. | title = Overestimation of ulcerative colitis due to melanosis coli. | journal = Acta Gastroenterol Latinoam | volume = 40 | issue = 4 | pages = 351-3 | month = Dec | year = 2010 | doi = | PMID = 21375218 }}</ref> | *Presence may lead to endoscopic misinterpretation of colitis severity.<ref name=pmid21375218>{{Cite journal | last1 = Zapatier | first1 = JA. | last2 = Schneider | first2 = A. | last3 = Parra | first3 = JL. | title = Overestimation of ulcerative colitis due to melanosis coli. | journal = Acta Gastroenterol Latinoam | volume = 40 | issue = 4 | pages = 351-3 | month = Dec | year = 2010 | doi = | PMID = 21375218 }}</ref> | ||
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==Gross== | ==Gross== | ||
*Brown pigmentation of the mucosa, | *Brown pigmentation of the mucosa, especially cecum and proximal colon.<ref name=pmid18666316/> | ||
**Less pigmentation distal. | |||
Note: | |||
*May also been seen in the [[small intestine]].<ref name=pmid18666316>{{cite journal |author=Freeman HJ |title="Melanosis" in the small and large intestine |journal=World J. Gastroenterol. |volume=14 |issue=27 |pages=4296-9 |year=2008 |month=July |pmid=18666316 |doi= |url=http://www.wjgnet.com/1007-9327/14/4296.asp}}</ref> | |||
===Endoscopic image=== | ===Endoscopic image=== | ||
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***Melanosis coli. | ***Melanosis coli. | ||
**Old haemorrhage, i.e. hemosiderin-laden macrophages (may be demonstrated with ''[[Prussian blue stain]]''<ref>URL: [http://education.vetmed.vt.edu/curriculum/VM8054/labs/Lab2/Examples/exprussb.htm http://education.vetmed.vt.edu/curriculum/VM8054/labs/Lab2/Examples/exprussb.htm]. Accessed on: 5 May 2010.</ref>). | **Old haemorrhage, i.e. hemosiderin-laden macrophages (may be demonstrated with ''[[Prussian blue stain]]''<ref>URL: [http://education.vetmed.vt.edu/curriculum/VM8054/labs/Lab2/Examples/exprussb.htm http://education.vetmed.vt.edu/curriculum/VM8054/labs/Lab2/Examples/exprussb.htm]. Accessed on: 5 May 2010.</ref>). | ||
**Melanin (from melanocytes) - rare in colon (may be demonstrated with a ''[[Fontana-Masson stain]]''<ref>URL: [http://education.vetmed.vt.edu/curriculum/VM8054/labs/Lab2/Examples/exfontana.htm http://education.vetmed.vt.edu/curriculum/VM8054/labs/Lab2/Examples/exfontana.htm]. Accessed on: 5 May 2010.</ref> - | **Melanin (from melanocytes) - rare in colon (may be demonstrated with a ''[[Fontana-Masson stain]]''<ref>URL: [http://education.vetmed.vt.edu/curriculum/VM8054/labs/Lab2/Examples/exfontana.htm http://education.vetmed.vt.edu/curriculum/VM8054/labs/Lab2/Examples/exfontana.htm]. Accessed on: 5 May 2010.</ref>). | ||
***Fontana-Masson ''not'' useful for differentiating from pseudomelanosis, as pseudomelanosis is Fontana-Masson positive.<ref name=pmid2346038>{{Cite journal | last1 = Park | first1 = C. | last2 = Cho | first2 = NH. | last3 = Jeong | first3 = HJ. | title = Melanosis coli--histochemical and immunohistochemical comparison of the pigments of melanosis coli and Dubin-Johnson syndrome. | journal = Yonsei Med J | volume = 31 | issue = 1 | pages = 27-32 | month = Mar | year = 1990 | doi = | PMID = 2346038 }}</ref> | |||
**Foreign material (e.g. tattoo pigment) - not seen in GI tract. | **Foreign material (e.g. tattoo pigment) - not seen in GI tract. | ||
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Image:Melanosis_coli_high_mag.jpg | Melanosis coli - high mag. (WC/Nephron) | Image:Melanosis_coli_high_mag.jpg | Melanosis coli - high mag. (WC/Nephron) | ||
</gallery> | </gallery> | ||
Another case: | |||
<gallery> | |||
Image:Pseudomelanosis coli - intermed mag.jpg | Melanosis coli - intermed. mag. (WC/Nephron) | |||
Image:Pseudomelanosis coli - high mag.jpg | Melanosis coli - high mag. (WC/Nephron) | |||
Image:Pseudomelanosis coli - very high mag.jpg | Melanosis coli - very high mag. (WC/Nephron) | |||
</gallery> | |||
==Stains== | ==Stains== | ||
*Can be demonstrated with a [[PAS stain]].<ref name=pmid9283862>{{cite journal |author=Benavides SH, Morgante PE, Monserrat AJ, Zárate J, Porta EA |title=The pigment of melanosis coli: a lectin histochemical study |journal=Gastrointest. Endosc. |volume=46 |issue=2 |pages=131–8 |year=1997 |month=August |pmid=9283862 |doi= |url=}}</ref> | *Can be demonstrated with a [[PAS stain]].<ref name=pmid9283862>{{cite journal |author=Benavides SH, Morgante PE, Monserrat AJ, Zárate J, Porta EA |title=The pigment of melanosis coli: a lectin histochemical study |journal=Gastrointest. Endosc. |volume=46 |issue=2 |pages=131–8 |year=1997 |month=August |pmid=9283862 |doi= |url=}}</ref> | ||
Note: | |||
*[[Fontana-Masson stain]] is ''not'' useful for differentiating pseudomelanosis from true melanin pigment, as pseudomelanosis is Fontana-Masson positive.<ref name=pmid2346038>{{Cite journal | last1 = Park | first1 = C. | last2 = Cho | first2 = NH. | last3 = Jeong | first3 = HJ. | title = Melanosis coli--histochemical and immunohistochemical comparison of the pigments of melanosis coli and Dubin-Johnson syndrome. | journal = Yonsei Med J | volume = 31 | issue = 1 | pages = 27-32 | month = Mar | year = 1990 | doi = | PMID = 2346038 }}</ref> | |||
==Sign out== | ==Sign out== | ||
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*[[Gastrointestinal pathology]]. | *[[Gastrointestinal pathology]]. | ||
*[[Colon]]. | *[[Colon]]. | ||
*[[Small bowel pseudomelanosis]]. | |||
==References== | ==References== | ||