Soo Jin Jung, et al: Malakoplakia of the Kidney in a Patient with Secondary Adrenal Insufficiency Figure 2. Renal biopsy (photomicrograph). (A) shows histiocytes with acellular basophilic precipitations (arrow) (H&E, ×400). (B) shows concentric, acellular basophilic precipitation (a.k.a Michaelis-Gutmann bodies) demonstrating calcium deposition (von Kossa stain, ×400). urine culture. Considering the laboratory and radiologic findings, intravenous antibiotic treatment was started (ubacillin 1,500 mg a day) for suspected actinomycosis. No specific lesion was found at the colonoscopy performed to confirm the diagnosis of actinomycosis. On the 12th day after admission, we conducted an ultra- sonography-guided renal biopsy. The histology of the lesion showed a collection of foamy histiocytes also known as von Hansemann cells with von-kossa stain positive spheres (Michelis- Gutmann body) (Figure 2). These findings are consistent with Malakoplakia. The patient presented dysuria and urgency, and antibiotic treatment was changed to oral ciprofloxacin (500 mg a day). On the 15th day after admission, she was discharged, as her presenting symptoms and laboratory findings were improved. About 4 months after discharge, the patient was readmitted presenting with general weakness for one month. The findings of the abdomen-pelvic CT conducted upon readmission (Figure 1B) showed that the extent of the malakoplakia in the perirenal space had decreased since 9 week prior, as she had been taking the oral antibiotics. She has had follow-up in our outpatient clinic ever since, taking oral trimethoprim-sulfamethoxazole. DISCUSSION Malakoplakia is an uncommon but distinctive type of chronic granulomatous inflammation. Upon microscopic examination, 370 | Vol. 32, No. 6 Sep 2011 malakoplakia is characterized by the presence of sheets of histiocytes with granular cytoplasm (von Hansemann cells) and the formation of intracellular bacterial inclusions called Michaelis- Gutmann bodies.3-7) The pathogenesis is poorly understood, but it is thought to result from acquired bactericidal defects in macrophages occurring mostly in patients with chronic debility or immunosuppression, a kidney transplant requiring steroids, or azathioprine.8,9) These observations suggest that an altered immune response may play a role in the pathogenesis of the disease. Individuals with diabetes mellitus have a greater frequency and severity of infection. From the earliest reports on studies of adrenocortical function, there has been impressive evidence that adrenocortical hormone, and more specifically cortisol, is essential for normal immunity. Otherwise, prednisone, triamcinolone, dexamethasone and similar commercially popular steroids have the dangerous side- effect of lowering resistance to infection, which is common to all known glucocorticoids.10) According to previous studies, gram-negative bacteria, particularlyEscherichia coli , have been isolated from involved sites of genitourinary malakoplakia in more than two-thirds of patients.11) Bacteria other than yeast were not isolated in the urine culture in the present case with cystitis because the patient was on antibiotic therapy before admission to our hospital. Although we did not carry out a detailed investigation of the patient’s immunity, we believe that unilateral renal malakoplakia extending to the perirenal space and the descending colon, as observed in the present case, may result Korean J Fam Med