Kidney nontumor
Tubular and interstitial diseases
Malakoplakia

Author: Nikhil Sangle, M.D. (see Authors page)

Revised: 6 February 2018, last major update March 2015

Copyright: (c) 2002-2018, PathologyOutlines.com, Inc.

PubMed Search: Malakoplakia [title] kidney

Cite this page: Sangle, N. Malakoplakia. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/kidneymalakoplakia.html. Accessed February 19th, 2018.
Definition / general
  • Also spelled malacoplakia
  • Foamy macrophages with PAS+ granular cytoplasm and Michaelis-Gutmann bodies (may be due to deposition of amorphous salts, Am J Surg Pathol 1984;8:151)
  • Associated with transplants
  • May be due to defective macrophage function that blocks lysosomal degradation of engulfed bacteria, filling up cytoplasm with undigested debris
Case reports
Gross description
  • Soft, yellow mucosal plaques
Gross images

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Yellowish rubbery solid mass

Microscopic (histologic) description
  • Foamy macrophages with PAS+ granular cytoplasm due to phagosomes stuffed with bacterial debris and Michaelis-Gutmann bodies (laminated mineralized concretions)
  • May have rare Michaelis-Gutmann bodies, late fibrous stage (Am J Surg Pathol 1989;13:225)
Microscopic (histologic) images

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Michaelis-Gutmann bodies, high mag

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Expansion of the interstitium

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von Kossa stain

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Infiltration of sheets

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Histiocytes

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CD68+

Virtual slides

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Kidney

Positive stains
Electron microscopy description
  • Intracellular calcific inclusions
Electron microscopy images

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Tongue mass

Differential diagnosis