Urology Journal UNRC/IUA 218 Renal Malakoplakia Simulating Neoplasm in a Child: Successful Medical Management KAJBAFZADEH AM*, BAHARNOORI M Department of Pediatric Urology and Renal Transplantation, Children Medical Center, Tehran University of Medical Sciences, Tehran, Iran KEY WORDS: renal malakoplakia, Wilm's, bethanechol chloride, macrophage, diagnosis Vol. 1, No. 3, 218-220 Summer 2004 Printed in IRAN Introduction Renal malakoplakia (RM) is a rare granuloma- tous disorder of adults, with less than 8 cases reported in pediatric age group in the literature. Published cases of RM were collected form the archival literature by searching the MEDLINE database and by reviewing bibliographic refer- ences contained in articles on renal malakoplakia. Ninety-six cases of RM have been published over the past 37 years. Renal malakoplakia presents with fever, flank pain, and a palpable mass, which may be con- fused with a renal tumor or other infectious processes. The clinical diagnosis of renal malako- plakia is difficult and usually only proved by pathologic findings of Michaelis-Gutmann bodies after nephrectomy. We report a child with renal parenchymal malakoplakia presenting with a renal neoplasm and successfully treated med- ically with no recurrence in a five year follow-up period. Case Report A 10-year-old boy suffering form fever and headache for 20 days before admission in the pediatric infectious disease ward had been evalu- ated as a fever of unknown origin (FUO) at a local hospital. He was initially diagnosed as Salmonellosis. Antibiotic regimen was not effec- tive (a 7 day course of chloramphenicol). The patient was transferred to our urology depart- ment with the initial diagnosis of huge renal mass, most probably a Wilm's tumor. On physical examination the child was severely ill, with day and night fever, tachycardia, and right flank ten- derness. A huge soft tissue mass was noted on the right upper quadrant, fixed to the surround- ing muscles. His erythrocyte sedimentation rate (ESR) was 110 mm/h in the first hour (normal 5 to 10 mm/h). All admission laboratory data were normal except for mild anemia and moderate leukocytosis. Renal ultrasound showed a right kidney huge solid mass with some cystic forma- tion with mixed echo pattern. Abdominal CT scan confirmed the right renal solid mass measuring 111 × 69 × 61 mm with some necrosis and cyst formation (fig. 1). On physical examination, the child was cachectic with a large right flank mass. Renal cortical scan by 99m Tc dimercaptosuccinic acid (DMSA) showed normal left kidney with a large photopenic area at the right lateral renal border (fig. 2). A true cut needle biopsy failed and an open biopsy was taken from the right flank mass. The histopathological reports showed sever inflammation with infiltration of foamy his- tiocytes, compatible with malakoplakia (fig. 3). Following confirmation of initial diagnosis, a trial treatment with bethanechol chloride, 12.5 mg three times daily, trimethoprim-sulfamethoxazole, one adult tablet per 12 hours, and ascorbic acid, 500 mg three times daily for 21 days, was initiat- ed. He was afebrile three days after starting the new regimen. The general condition, as well as his appetite, improved. A repeat renal ultrasound and a CT scan confirmed dramatic renal mass shrinkage and decrease in the size and appear- ance of the mass (fig. 4) three weeks following the treatment. Subsequently, the patient was fol- lowed for 46 months and renal ultrasound showed normal renal size with no detectable tumor. Discussion The most common presenting signs and symp- toms of renal malakoplakia are fever, flank pain, or a palpable flank mass. Two basic patterns of Accepted for publication in April 2004 *Corresponding author: 2nd Floor, No. 36, 7th Street, Saadat-Abad, Tehran 19987, Iran. email: kajbafzd@sina.tums.ac.ir RENAL MALAKOPLAKIA SIMULATING NEOPLASM IN A CHILD: SUCCESSFUL MEDICAL MANAGEMENT 219 malakoplakia have been described: multifocal and unifocal.(1,2) Multifocal type accounts for 75% of the reported cases and is bilateral in about half of the cases. Unifocal disease usually appears as a large yellow-gray mass measuring 2.5 cm to 9 cm in diameter.(1) The mass is usually smooth and well marginated and central necrosis or cyst formation may be present. Histological examina- tion reveals aggregates of large histiocytic cells (Von Hansemann cells) admixed with an infiltrate FIG. 2. Intravenous urogram showed a soft tissue mass on the lateral border of right kidney causing caliceal elonga- tion and distortion. FIG. 3. The Renal cortical scan by Tc-99m DMSA showed normal left kidney with a photopenic area at the right lat- eral renal border. FIG. 4. CT scan three weeks following medical management noted dramatic mass shrinkage. FIG. 1. Abdominal CT Scan before medical management showed right renal solid mass with some necrosis and cyst formation. RENAL MALAKOPLAKIA SIMULATING NEOPLASM IN A CHILD: SUCCESSFUL MEDICAL MANAGEMENT 220 of lymphocytes, plasma cells, and interspersed well-defined bundles of fibroblasts and collagen. Von Hansemann histiocytes contain Michaelis- Gutmann bodies, concentrically laminate and cal- cific inclusions pathognomonic of malakoplakia. Patients with solitary kidney or bilateral upper tract involvement may present with azotemia or uremia. Dramatic improvement has also been reported in patients treated with cholinergic agents and ascorbic acid.(2) Both agents have cor- rected cellular abnormalities as well as enhancing phagocytosis by improving microtubule and vac- uole formation. Cholinergic actions may also include improving bactericidal function through enhancing super oxide production and release. It is known that the cholinergic agonists raise intra- cellular cyclic guanine monophosphate (cGMP)/cyclic adenosine monophosphate (cAMP) ratio and stimulate the production of tumor necrosis factor that enhances the microbiocidal function of macrophages.(3) References 1. Hartman DS, Davis CJ Jr, Lichtenstein JE, Goldman SM. Renal parenchymal malakoplakia. Radiology 1980; 136: 33-42. 2. Abdou NI, NaPombejara C, Sagawa A, et al. Malakoplakia: evidence for monocyte lysosomal abnor- mality correctable by cholinergic agonist in vitro and in vivo. N Engl J Med 1977; 297: 1413-19. 3. Kajbafzadeh AM. Malakoplakia of the testis [correspon- dence]. Br J Urol 1995; 76: 276.