Difference between revisions of "Pseudomelanosis coli"

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#redirect [[Colon#Pseudomelanosis_coli]]
{{ Infobox diagnosis
| Name      = {{PAGENAME}}
| Image      = Melanosis_coli_intermed_mag.jpg
| Width      =
| Caption    = Pseudomelanosis coli. [[H&E stain]].
| Synonyms  = melanosis coli
| Micro      = brown granular pigment in the lamina propria, abundant
| Subtypes  =
| LMDDx      = hemorrhage, [[melanocytic lesion]] (rarely)
| Stains    = [[PAS stain|PAS]] +ve, [[Prussian blue stain|Prussian blue]] -ve, [[Fontana-Masson stain|Fontana-Masson]] +ve
| IHC        =
| EM        =
| Molecular  =
| IF        =
| Gross      =
| Grossing  =
| Site      = [[colon]], [[cecum]], occasionally [[small intestine]]
| Assdx      =
| Syndromes  =
| Clinicalhx = use of laxatives and herbals
| Signs      =
| Symptoms  =
| Prevalence =
| Bloodwork  =
| Rads      =
| Endoscopy  = brown discolouration of the mucosa, esp. proximal colon and cecum
| Prognosis  = benign
| Other      =
| ClinDDx    = [[colitis]]
}}
{{ Infobox external links
| Name          = {{PAGENAME}}
| EHVSC          =
| EHVSC_mult    =
| pathprotocols  =
| wikipedia      = melanosis coli
| pathoutlines  =
}}
'''Pseudomelanosis coli''', also known as '''melanosis coli''',<ref>URL: [http://www.medicinenet.com/melanosis_coli/article.htm http://www.medicinenet.com/melanosis_coli/article.htm]. Accessed on: 4 March 2011.</ref> is a relatively common benign change seen in the [[colon]].
 
==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>
*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>
 
===Epidemiology===
*Classically associated with anthracene containing laxative (e.g. Senokot) use and herbal remedies.<ref name=pmid18666316/>
**May be seen in individuals not using laxatives.<ref name=pmid9600362/>
*Seen in (long-standing) [[inflammatory bowel disease]], especially [[ulcerative colitis]].<ref name=pmid9600362>{{Cite journal  | last1 = Pardi | first1 = DS. | last2 = Tremaine | first2 = WJ. | last3 = Rothenberg | first3 = HJ. | last4 = Batts | first4 = KP. | title = Melanosis coli in inflammatory bowel disease. | journal = J Clin Gastroenterol | volume = 26 | issue = 3 | pages = 167-70 | month = Apr | year = 1998 | doi =  | PMID = 9600362 }}</ref>
 
==Gross==
*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===
<gallery>
Image:Melanosis_coli.jpg | Melanosis coli - endoscopic image. (WC)
</gallery>
 
==Microscopic==
Features:
*Brown granular pigment - in the lamina propria.
**Typically more prominent in the cecum and proximal colon.<ref name=pmid18666316/>
 
Notes:
*DDx of brown pigment:
**Lipofuscin - comes with age (can be demonstrated with a ''[[PAS stain]]''<ref name=pmid5463681 >{{cite journal |author=Kovi J, Leifer C |title=Lipofuscin pigment accumulation in spontaneous mammary carcinoma of A/Jax mouse |journal=J Natl Med Assoc |volume=62 |issue=4 |pages=287–90 |year=1970 |month=July |pmid=5463681 |pmc=2611776 |doi= |url=http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2611776/pdf/jnma00512-0077.pdf}}</ref> or ''[[Kluver-Barrera stain]]''<ref>URL: [http://education.vetmed.vt.edu/curriculum/VM8054/labs/Lab2/Examples/exkluvbarr.htm http://education.vetmed.vt.edu/curriculum/VM8054/labs/Lab2/Examples/exkluvbarr.htm]. Accessed on: 5 May 2010.</ref>).
***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>).
**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.
 
===Images===
<gallery>
Image:Melanosis_coli_low_mag.jpg | Melanosis coli - low mag. (WC/Nephron)
Image:Melanosis_coli_intermed_mag.jpg | Melanosis coli - intermed. mag. (WC/Nephron)
Image:Melanosis_coli_high_mag.jpg | Melanosis coli - high mag. (WC/Nephron)
</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==
*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==
<pre>
ASCENDING COLON, BIOPSY:
- PSEUDOMELANOSIS COLI.
- NEGATIVE FOR ACTIVE COLITIS.
- NEGATIVE FOR DYSPLASIA.
</pre>
 
==See also==
*[[Gastrointestinal pathology]].
*[[Colon]].
*[[Small bowel pseudomelanosis]].
 
==References==
{{Reflist|2}}


[[Category:Diagnosis]]
[[Category:Diagnosis]]
[[Category:Colon]]

Latest revision as of 18:08, 24 May 2020

Pseudomelanosis coli
Diagnosis in short

Pseudomelanosis coli. H&E stain.
Synonyms melanosis coli
LM brown granular pigment in the lamina propria, abundant
LM DDx hemorrhage, melanocytic lesion (rarely)
Stains PAS +ve, Prussian blue -ve, Fontana-Masson +ve
Site colon, cecum, occasionally small intestine
Clinical history use of laxatives and herbals
Endoscopy brown discolouration of the mucosa, esp. proximal colon and cecum
Prognosis benign
Clin. DDx colitis
Pseudomelanosis coli
External resources
Wikipedia melanosis coli

Pseudomelanosis coli, also known as melanosis coli,[1] is a relatively common benign change seen in the colon.

General

  • Not melanin as the name melanosis coli suggests; it is actually lipofuscin (in macrophages).[2]
  • Endoscopist may see brown pigmentation of mucosa and suspect the diagnosis.
  • Presence may lead to endoscopic misinterpretation of colitis severity.[3]

Epidemiology

Gross

  • Brown pigmentation of the mucosa, especially cecum and proximal colon.[2]
    • Less pigmentation distal.

Note:

Endoscopic image

  • Melanosis coli - endoscopic image. (WC)

Microscopic

Features:

  • Brown granular pigment - in the lamina propria.
    • Typically more prominent in the cecum and proximal colon.[2]

Notes:

  • DDx of brown pigment:
    • Lipofuscin - comes with age (can be demonstrated with a PAS stain[5] or Kluver-Barrera stain[6]).
      • Melanosis coli.
    • Old haemorrhage, i.e. hemosiderin-laden macrophages (may be demonstrated with Prussian blue stain[7]).
    • Melanin (from melanocytes) - rare in colon (may be demonstrated with a Fontana-Masson stain[8]).
      • Fontana-Masson not useful for differentiating from pseudomelanosis, as pseudomelanosis is Fontana-Masson positive.[9]
    • Foreign material (e.g. tattoo pigment) - not seen in GI tract.

Images

  • Melanosis coli - low mag. (WC/Nephron)

  • Melanosis coli - intermed. mag. (WC/Nephron)

  • Melanosis coli - high mag. (WC/Nephron)

Another case:

  • Melanosis coli - intermed. mag. (WC/Nephron)

  • Melanosis coli - high mag. (WC/Nephron)

  • Melanosis coli - very high mag. (WC/Nephron)

Stains

Note:

  • Fontana-Masson stain is not useful for differentiating pseudomelanosis from true melanin pigment, as pseudomelanosis is Fontana-Masson positive.[9]

Sign out

ASCENDING COLON, BIOPSY:
- PSEUDOMELANOSIS COLI.
- NEGATIVE FOR ACTIVE COLITIS.
- NEGATIVE FOR DYSPLASIA.

See also

References

  1. ↑ URL: http://www.medicinenet.com/melanosis_coli/article.htm. Accessed on: 4 March 2011.
  2. ↑ 2.0 2.1 2.2 2.3 2.4 Freeman HJ (July 2008). ""Melanosis" in the small and large intestine". World J. Gastroenterol. 14 (27): 4296-9. PMID 18666316. http://www.wjgnet.com/1007-9327/14/4296.asp.
  3. ↑ Zapatier, JA.; Schneider, A.; Parra, JL. (Dec 2010). "Overestimation of ulcerative colitis due to melanosis coli.". Acta Gastroenterol Latinoam 40 (4): 351-3. PMID 21375218.
  4. ↑ 4.0 4.1 Pardi, DS.; Tremaine, WJ.; Rothenberg, HJ.; Batts, KP. (Apr 1998). "Melanosis coli in inflammatory bowel disease.". J Clin Gastroenterol 26 (3): 167-70. PMID 9600362.
  5. ↑ Kovi J, Leifer C (July 1970). "Lipofuscin pigment accumulation in spontaneous mammary carcinoma of A/Jax mouse". J Natl Med Assoc 62 (4): 287–90. PMC 2611776. PMID 5463681. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2611776/pdf/jnma00512-0077.pdf.
  6. ↑ URL: http://education.vetmed.vt.edu/curriculum/VM8054/labs/Lab2/Examples/exkluvbarr.htm. Accessed on: 5 May 2010.
  7. ↑ URL: http://education.vetmed.vt.edu/curriculum/VM8054/labs/Lab2/Examples/exprussb.htm. Accessed on: 5 May 2010.
  8. ↑ URL: http://education.vetmed.vt.edu/curriculum/VM8054/labs/Lab2/Examples/exfontana.htm. Accessed on: 5 May 2010.
  9. ↑ 9.0 9.1 Park, C.; Cho, NH.; Jeong, HJ. (Mar 1990). "Melanosis coli--histochemical and immunohistochemical comparison of the pigments of melanosis coli and Dubin-Johnson syndrome.". Yonsei Med J 31 (1): 27-32. PMID 2346038.
  10. ↑ Benavides SH, Morgante PE, Monserrat AJ, Zárate J, Porta EA (August 1997). "The pigment of melanosis coli: a lectin histochemical study". Gastrointest. Endosc. 46 (2): 131–8. PMID 9283862.
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