Xanthogranulomatous pyelonephritis and malacoplakia of the bladder in a middle aged female.

We describe the case of a female with xanthogranulomatous pyelonephritis and malacoplakia of the bladder, presenting with recurrent urinary tract infection and renal mass. The genitourinary tract should be explored to evaluate the coexistence of these two diseases. Nephrectomy and bladder mass resection is warranted to maintain sterile urine. This case represents an unusual instance of the synchronic appearance of xanthogranulomatous pyelonephritis and malacoplakia of the bladder, implying a common pathogenesis for two related diseases from a different histological spectrum, in which the urinary obstruction serves as a promoting factor for the stepwise transformation of morphogenesis.