2012 Volume 34 Issue 3 Pages 265-270
This is a case report of a 65-year-old female with malakoplakia in the urinary bladder. An ultrasound scan showed many tumor-like polyp lesions, where a transurethral resection was performed. Since the lesions revealed gross papillary neoplasms, malignancy was suspected. However, histpathological examination showed an aggregation of many infiltrating histiocytes containing characteristic Michaelis-Gutmann bodies positively reactive with von Kossa staining, indicating a typical case of malakoplakia of the urinary bladder. Immunohistochemical study demonstrated that the cytoplasms of the histiocytes were focally positive for an anti-Escherichia coli antibody. One of the etiologies of malakoplakia is infection by Escherichia coli, which is supported by our data.