Malacoplakia of the urinary tract is an uncommon chronic granulomatous inflammatory disease of the bladder wall. Malakoplakia (meaning "soft plaque") can affect any organ, but the urinary bladder is the commonest location.
Malacoplakia has a peak incidence in middle age and has a reported female-to-male ratio of 4:1 1. The disease is common in patients who are immunocompromised or in those with chronic diseases such as AIDS or diabetes mellitus.
Presenting symptoms include gross haematuria and signs of urinary tract infection, with Escherichia coli infection being very commonly found to coexist.
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.
Michaelis-Gutmann bodies are a histologic hallmark which corresponds to intracellular inclusions in the large histiocytes containing calcium 2. Identifying these may require special stains.
Within the urinary tract, the bladder is the most frequently affected organ (40% of patients with malacoplakia).
Imaging characteristics of malacoplakia are varied, and most commonly observed within the bladder, although plaques may also occur in the ureters.
Malacoplakia 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 millimetres to several centimetres. Occasionally, malacoplakia can be locally aggressive and invades surrounding structures even causing bone erosions 1.
Treatment and prognosis
Although malacoplakia may be extremely aggressive, invading the perivesical space, and it can even cause bone destruction, non-surgical medical management is the mainstay of treatment, and as such, biopsy for accurate diagnosis is essential.
Treatment regimens include antibiotics, ascorbic acid, and a cholinergic agonist 1.
History and etymology
The term derives from "μαλακία" (malakia: "soft") and "μαλακία" (plakia: "slab/plaque").
The terms "malaco"plakia and "malako"plakia are used interchangeably as latinisations of "μαλακία".
The term was first used by Von Hansseman, but the condition was first described by Michaelis and Gutmann in 1902 1.
- multifocal or long-segment strictures
- calcification is commonly seen
- squamous metaplasia of the urothelium
- more common in bladder
- reactive proliferative changes of the urothelium causing multiple small subepithelial cysts
- 1. Michaelis L & Gutmann D. Ueber Einschlüsse in Blasentumoren. Zeitschrift für klinische Medizin 1902;47:208
- 2.Wong-you-cheong JJ, Woodward PJ, Manning MA et-al. From the archives of the AFIP: Inflammatory and nonneoplastic bladder masses: radiologic-pathologic correlation. Radiographics. 26 (6): 1847-68. doi:10.1148/rg.266065126 - Pubmed citation
- 3. Haaga JR, Boll D. CT and MRI of the whole body. Mosby. (2009) ISBN:0323053750. Read it at Google Books - Find it at Amazon
- 4. Dasgupta P, Womack C, Turner AG et-al. Malacoplakia: von Hansemann's disease. BJU Int. 1999;84 (4): 464-9. Pubmed citation