Bladder
Cystitis
Malakoplakia

Author: Monika Roychowdhury, M.D.see Authors page)

Revised: 31 May 2016, last major update March 2015

Copyright: (c) 2003-2016, PathologyOutlines.com, Inc.

PubMed Search: Malakoplakia [title] bladder
Cite this page: Malakoplakia. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/bladdermalakoplakia.html. Accessed December 10th, 2016.
Definition / General
  • Rare histiocytic disease that occurs in all organs
  • Common in GU tract, particularly bladder
  • Also gastrointestinal tract (most commonly colon, followed by stomach and duodenum), central nervous system, female genital tract (Radiographics 2006;26:1847)
  • Single or multiple tumors
  • Often misdiagnosed clinically as a malignant condition
Terminology
  • First described by Michaelis and Gutmann in 1902 and later named by Von Hansseman
  • "Malakoplakia" comes from Greek words malakos (soft) and plakos (plaque)
Epidemiology
  • More common in immunocompromised (HIV, renal transplant recipients) and women
  • Mean age at diagnosis is fifth decade
  • Rare in children
Etiology
  • Caused by defects in phagocytic or degradative functions of histiocytes in response to gram negative coliforms (E. coli or Proteus) that results in chronic inflammatory state, followed by intracellular deposition of iron and calcium (known as Michaelis-Gutmann bodies)
Clinical Features
Case Reports
Treatment
  • Antibiotics that concentrate in macrophages (quinolones or trimethoprim-sulfamethoxazole), antibiotics directed against E. coli plus surgery
  • Possibly bethanechol (may correct decreased cGMP levels that may interfere with complete bacterial killing, eMedicine)
  • Discontinuation of immunosuppressive drug therapy
Micro Description
  • Can be divided in 3 stages:
    • Initial inflammatory stage
    • Classic stage with abundant Michaelis-Gutmann bodies
    • Third stage with progressive fibrous tissue and scarring
  • Foamy epithelioid histiocytes with PAS+ granular eosinophilic cytoplasm in lamina propria, some lymphocytes and occasional giant cells
  • Histiocytes have increased number of phagosomes containing non-digested bacteria (usually E. coli or Proteus), contain Michaelis-Gutmann bodies (iron containing, cytoplasmic laminated mineralized concretions)
Micro Images

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Case of the Week #131


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COW #131, von Kossa stain

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COW #131, iron stain



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Malakoplakia (arrows at Michaelis-Gutmann bodies)


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von Kossa calcium stain

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CD68

Virtual Slides

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Bladder malakoplakia

Electron Microscopy Description
  • Macrophages have phagosomes that are packed with undigested bacterial products