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Malacoplakia: Pathology, Diagnosis and Treatment

Definition of Malacoplakia

Malacoplakia is a chronic infection/inflammation of the urinary tract, the gastrointestinal tract, and other organ systems, forming whitish-gray deposits (Dasgupta et al., 1999) (Dalla-Palma and Pozzi-Mucelli, 2000).

Epidemiology of Malacoplakia

Malacoplakia is rare, the most common urological manifestation is the urinary bladder. Female:male ratio = 4:1

Malacoplakia of the bladder: cystoscopy shows multiple whitish-gray, plaque-like protrusions of the mucosa.

Etiology of Malacoplakia

Malacoplakia is caused by a defect in the bacterial decomposition within phagosomes; this leads to the formation of intracellular Michaelis-Gutmann bodies (see pathology). Chronic urinary tract infection is the main risk factor for malacoplakia. Further risk factors are immune deficiency, malignancy, or other consuming systemic disease.

Pathology of Malacoplakia

Macroscopy:

Typical malacoplakia lesions are whitish-gray, plaque-like protrusions of the mucosa; they may have a hemorrhagic rim. The lesion becomes indurated due to scarring. Most commonly, malacoplakia affects the urinary bladder in women, but in principle, all urogenital organs might be involved.

Histology:

Large histiocytes (Hansemann cells) with small basophilic intracytoplasmic inclusions (Michaelis-Gutmann bodies) of extracellular matrix are pathognomonic for malacoplakia.

Signs and Symptoms of Malacoplakia

Most patients are older than 50 years and suffer from a consuming disease and chronic urinary tract infections.

• Bladder manifestation: dysuria, pollakisuria, and possibly hematuria.
• Lesions of the ureter: hydronephrosis with flank pain or fever.
• Renal lesions: radiological signs of a tumor, nonspecific symptoms.
• Testicular lesions lead to pain and scrotal swelling.

Diagnostic Workup

• Urine culture, blood culture.
• The radiological tests depend on the affected organ and reveal masses or filling defects (Ultrasound, intravenous urography, abdominal CT scan).
• Cystoscopy [malacoplakia of the bladder] or ureteroscopy with biopsy of lesions.

Treatment of Malacoplakia

Antibiotic therapy:

Long-term antibiotic treatment with fluoroquinolones, co-trimoxazole, rifampin, sulfonamides, or doxycycline.

Surgical treatment:

Transurethral resection of bladder lesions, internal ureteral stenting in case of hydronephrosis, (partial) nephrectomy in case of renal malacoplakia, depending on symptoms and organ function.

Prognosis of Malacoplakia

Patients with malacoplakia of the bladder or unilateral renal manifestation have a good prognosis after adequate treatment. However, serious complications are possible in patients with bilateral renal manifestation or malacoplakia after kidney transplantation.

References

Dasgupta u.a. 1999 DASGUPTA, P. ; WOMACK, C. ; TURNER, A. G. ; BLACKFORD, H. N.: Malacoplakia: von Hansemann’s disease.
In: BJU Int
84 (1999), Nr. 4, S. 464–9

Dalla-Palma und Pozzi-Mucelli 2000 DALLA-PALMA, L. ; POZZI-MUCELLI, F.: [The imaging of chronic renal infections].
In: Radiologe
40 (2000), Nr. 6, S. 537–46

  Deutsche Version: Malakoplakie