Malacoplakia

Last revised by Dr Rania Adel Anan on 27 Sep 2022

Malacoplakia is an uncommon chronic granulomatous inflammatory disease that can affect essentially any part of the body but most frequently involves the bladder wall. 

Malacoplakia has a peak incidence in middle age and has a reported female-to-male ratio of 4:1 1. Other risk factors include immunosuppression, AIDS and diabetes mellitus

Presenting symptoms depend on the region involved.

In the most common setting, when the bladder is the site of diseases, patients present with gross hematuria, lower urinary tract symptoms and recurrent urinary tract infection (most commonly with Escherichia coli ). Papules, plaques and ulceration on direct visualization during flexible cystoscopy have been described 5

In the urinary system, although infection with E. coli is very often observed, impaired host bactericidal defenses and defective phagocytosis are considered an important part of the pathogenesis 1

Von Hansemann cells (ovoid histiocytes) which contain calcific Michaelis-Gutmann bodies are a histologic hallmark which is pathognomonic for this diagnosis 2,5. Identification may require special stains.

The urinary bladder is the most frequently affected organ (40% of patients with malacoplakia).

Imaging characteristics of malacoplakia are varied and depend on the region involved.

Malacoplakia is most commonly observed within the bladder, although plaques may also occur in the ureters.

It may present as multiple, polypoid, vascular, solid masses or as circumferential wall thickening, associated with vesicoureteral reflux and dilatation of the upper urinary tract. These masses vary in size from a few millimeters to several centimeters. Occasionally, malacoplakia can be locally aggressive and invade surrounding structures even causing bone erosions 1.  

Although malacoplakia may be extremely aggressive, invading the adjacent spaces and even causing bone destruction, non-surgical medical management is the mainstay of treatment. As such, biopsy for accurate diagnosis is essential. 

Treatment of urinary involvement usually includes antibiotics, ascorbic acid, and a cholinergic agonist 1.

The term derives from "μαλακία" (malakia: "soft") and "πλακία" (plakia"slab/plaque").

The terms "malaco"plakia and "malako"plakia are used interchangeably as latinisations of "μαλακία".

The term was first used by the German pathologist David Paul von Hansemann (1858-1920) 6, but the condition was first described by L Michaelis and D Gutmann in 1902 1.

The differential will vary greatly depending on the location of involvement. 

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Cases and figures

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