Prostate
Prostatitis
Malakoplakia

Author: Kenneth Iczkowski, M.D. (see Authors page)

Revised: 25 July 2016, last major update July 2016

Copyright: (c) 2002-2016, PathologyOutlines.com, Inc.

PubMed Search: Malakoplakia [title]

Definition / General
  • A peculiar form of tissue reaction to bacterial infection, usually gram negative
Etiology
  • Originates with an E. coli or Klebisella pneumoniae urinary tract infection
  • The host cells have a defect in lysosomal degradation of bacteria
  • Iron and calcium accumulate around undigested bacteria in macrophages, forming Michaelis-Gutmann bodies
Sites
  • Although it is mostly associated with bladder disease, the transition zone of the prostate may be involved (Int J Surg Pathol 2007;15:86)
  • Ages 47 +
Clinical Features
  • Prostate enlarged on clinical examination, suggestive of carcinoma; may resemble carcinoma on MRI (Radiographics 2016;36:162) or ultrasound
  • 8 cases have been reported in which prostatic adenocarcinoma was associated with the malakoplakia (Ann Diagn Pathol 2016;22:33)
Diagnosis
  • Von Kossa stain may be helpful in staining the calcium
Micro Description
  • Michaelis-Gutmann bodies are iron and calcium around a nidus of undigested bacteria
Micro Images

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Michaelis-Gutmann bodies (arrows)
Courtesy of Kenneth Iczkowski, M.D.



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Classic features of malakoplakia

Differential Diagnosis