Bladder malakoplakia mimicking a bladder tumor: A case report and brief review of the literature.

Malakoplakia is a rare granulomatous inflammatory disease that primarily affects the genitourinary tract and is often associated with coliform infections. In rare cases, it can mimic tumors; however, to date, to the best of our knowledge, no case of malakoplakia due to Morganella morganii mimicking as a tumor has been reported. The present study describes the case of a patient with bladder malakoplakia caused by Morganella morganii, mimicking a bladder tumor. A 78-year-old male patient presented with complaints of dysuria, urinary frequency, urgency and incontinence. Upon a urinalysis, a marked number of pus cells were observed, and an abdominal ultrasound revealed bladder wall thickening. Flexible cystoscopy revealed a tight urethra and multiple sessile masses in the bladder. A urine culture revealed infection with Morganella morganii, and the patient was treated with antibiotics. Following transurethral resection of the masses, histopathological analysis revealed von Hansemann cells and Michaelis-Gutmann bodies, confirming the diagnosis of malakoplakia. Immunohistochemistry was negative for AE1/AE3 and S100, but positive for CD68. In addition, 10 cases in the literature were reviewed; all patients in these cases were elderly or adults, apart from one case. Of note, 6 cases had Escherichia coli infection, and 1 case also had Pseudomonas aeruginosa infection. A total of 6 cases underwent mass resection, while 4 cases were managed conservatively; one of these experienced recurrence. On the whole, the present study demonstrates that bladder malakoplakia can also arise from infection with Morganella morganii and mimic a tumor; thus, it should be considered in the differential diagnosis of bladder inflammation or masses.