Small bowel pseudomelanosis

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Small bowel pseudomelanosis is benign change of the small bowel that mimics melanin deposition.

Small bowel pseudomelanosis
Diagnosis in short
[[File:Small bowel pseudomelanosis. H&E stain.|frameless|Template:Px|alt=]]
Small bowel pseudomelanosis - alt -- intermed mag.jpg

Synonyms pseudomelanosis duodeni (for duodenum)

LM dark pigment in the lamina propria macrophages
Stains iron stain +ve
Site small bowel, stomach

Associated Dx iron deficiency anemia, end-stage renal disease, hypertension
Clinical history iron supplementation
Prevalence rare
Endoscopy +/-dark spots
Prognosis benign

In the duodenum it is known as pseudomelanosis duodeni.

Pseudomelanosis is described in the stomach, duodenum and jejunum.[1]

General

  • Rare and benign.[2]
  • Consists of iron and lipofuscin.[3]

Associations in a series of 17 individuals:[4]

Note:

Gross/endoscopic

  • Dark spots ~35% of cases.[4]

Microscopic

Features:

  • Dark pigment in the lamina propria macrophages.

Images

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Stains

  • Prussian blue +ve ~80% of cases.[4]

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Small bowel

A. Stomach, Partial Excision as Part of a Sleeve Gastrectomy:
- Stomach wall within normal limits.

B. Small Bowel Wall, Partial Excision as Part of a Sleeve Gastrectomy: 
- Small bowel wall with iron containing macrophages in the mucosa,
  known as "pseudomelanosis", see comment.
- NEGATIVE for active inflammation.
- NEGATIVE for dysplasia and NEGATIVE for malignancy.

Comment:
Pseudomelanosis may be seen in the context of iron supplementation, hypertension 
and chronic renal failure. 

The macrophages are positive with an iron stain. 

See also

References

  1. Rustagi, T.; Mansoor, MS.; Gibson, JA.; Kapadia, CR. (Feb 2015). "Pseudomelanosis of stomach, duodenum, and jejunum.". J Clin Gastroenterol 49 (2): 124-6. doi:10.1097/MCG.0000000000000081. PMID 24492404.
  2. de Magalhães Costa, MH.; Fernandes Pegado, Mda G.; Vargas, C.; Castro, ME.; Madi, K.; Nunes, T.; Zaltman, C. (Mar 2012). "Pseudomelanosis duodeni associated with chronic renal failure.". World J Gastroenterol 18 (12): 1414-6. doi:10.3748/wjg.v18.i12.1414. PMID 22493558.
  3. Lin, HJ.; Tsay, SH.; Chiang, H.; Tsai, YT.; Lee, SD.; Yeh, YS.; Lo, GH. (Apr 1988). "Pseudomelanosis duodeni. Case report and review of literature.". J Clin Gastroenterol 10 (2): 155-9. PMID 2458404.
  4. 4.0 4.1 4.2 Giusto, D.; Jakate, S. (Feb 2008). "Pseudomelanosis duodeni: associated with multiple clinical conditions and unpredictable iron stainability - a case series.". Endoscopy 40 (2): 165-7. doi:10.1055/s-2007-995472. PMID 18253910.