From the Greek word meaning “soft plaque”.
Rare chronic granulomatous inflammatory disease most commonly affecting bladder but can affect many other organ systems.
Females 4:1 affected in urinary tract malacoplakia – most patients older than 50 with co-morbidities.
Increasingly described after solid organ transplants, particularly renal transplants.
Pathogenesis
Probably results from abnormal macrophage function and subsequent immunological and inflammatory reaction in response to bacterial infection – most patients have history of repeated E.coli infections.
Strong association in patients with immunosuppression and recurrent coliform infection.
Pathology
Characterised by large histiocytes (von Hansemann cells), and small basophilic calcific Michaelis-Gutmann bodies
Macrophages in malacoplakia also contain high levels of α1-antitrypsin which may help distinguish from other inflammatory disorders.
Clinical features
Bladder malacoplakia presents with bladder irritability and haematuria.
Cystoscopy shows mucosal plaques (soft, yellow or brown) and nodules which may become firm, sessile masses.
Distal ureteric stricturing can occur.
Imaging may mimic tumours in bladder or kidney – generally not calcified, hypodense masses. On ultrasound may be generally abnormal kidney with enlargement.
Treatment
Control of underlying UTIs.
TURBT / biopsy for histological diagnosis.
Nephrectomy if causing problems