Malacoplakia presenting as a large bladder mass

Abstract

A woman with a medical history significant for recurrent urinary tract infections and systemic histoplasmosis presented with persistent urinary urgency, frequency, dysuria, a weak urinary stream, and gross hematuria. Renal and bladder ultrasound scanning revealed normal kidneys and a mass within the bladder (Fig. 1). A urine culture grew more than 100,000 Escherichia coli. After the patient’s urinary tract infection was treated, she underwent cystoscopy, which revealed a lobulated, fungating tumor present circumferentially at the bladder neck and at the left lateral bladder wall. It was resected endoscopically, with subsequent resolution of all of her voiding complaints. Histologic examination of the specimen revealed malacoplakia (Fig. 2). She was subsequently treated with an extended course of oral antibiotics. Malacoplakia is characterized histologically by the presence of Michaelis-Gutmann bodies contained within von Hansemann macrophages. This likely represents phagolysosomes that contain partially digested bacterial debris. Malacoplakia occurs typically in immunocompromised patients who experience recurrent E. coli urinary tract infections. It predominates in females and occurs in both the upper and lower urinary tracts. Treatment ranges from antibiotic therapy to endoscopic resection and, in some cases, surgical removal of the organ. Malacoplakia is often mistaken for malignancy on imaging studies and on gross inspection and should be considered as a diagnosis in the type of patient described here.1,2