CASE OF THE WEEK
2020-33 / August 17
(Contributor: Cheng Wang)
A woman in her early 50s presented with multiple broad-based bladder mucosal lesions seen on cystoscopic examination.
Quiz
1. What is the correct diagnosis?
a. Metastatic carcinoma
b. Malakoplakia
c. Invasive high-grade urothelial carcinoma
d. Bladder endometriosis
e. Lymphoma
2. What is the name of the targetoid bodies, which are pathognomonic for this condition?
a. Michaelis-Gutman bodies
b. Aschoff bodies
c. Asbestos bodies
d. Howell-Jolly bodies
e. Psammoma bodies
3. A Von Kossa stain highlights the targetoid bodies by detecting chemicals containing which of the following minerals?
a. Magnesium
b. Iron
c. Calcium
d. Copper
e. Sodium
1. b
2. a
3. c
1. Malakoplakia
2. Michaelis-Gutman bodies
3. Calcium
Malakoplakia is caused by defects in phagocytic or degradative functions of histiocytes in response to bacterial infections (usually by gram-negative coliforms). It is a relatively uncommon lesion seen in patients with hematuria or signs of urinary tract infections. It occurs more common in women (4:1), older patients, and immunosuppressed patients (HIV-positive and renal transplant recipients). It can also occur, though less commonly, in the prostate, kidney, testis, lymph nodes, lungs, and bone. The typical mucosal lesion of malakoplakia is characterized by multiple yellow-brown, soft (malakos) plaques (plakos). Sometimes malakoplakia can form nodules or polypoid mass lesions, mimicking neoplasms.
Microscopically, malakoplakia is composed of sheets of von Hansemann histiocytes (macrophages with abundant granular cytoplasm) in the lamina propria. Careful search of Michaelis-Gutman bodies at high power view is key to make the correct diagnosis. The intracellular and extracellular target-like structures (Michaelis-Gutman bodies) are formed by deposition of calcium and iron phosphate on undigested bacterial components. The treatment includes using antibiotics that concentrate in macrophages and discontinuation of immunosuppressive drug therapy.
Current F. T. Malakoplakia of the Bladder. British Journal of Urology. 1987 vol:59 iss:6 pgs:559-563
Cheng Wang
Department of Pathology and Laboratory Medicine; Department of Urology
Dalhousie University and Nova Scotia Health Authority
Halifax, NS, Canada
Urinary bladder
bladder, malakoplakia, Michaelis-Gutman bodies