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ediatric Case Report

anthogranulomatousyelonephritis in an Adolescent

avid Chalmers, Sarah Marietti, and Christina Kim

anthogranulomatous pyelonephritis is a chronic, inflammatory disease of the kidney rarely found in the pediatricopulation. We report the case of a 16-year-old boy with fever, microscopic hematuria, and an enlarging cystic renalass on ultrasonography. The patient had no evidence of renal stones and no known risk factors, other than a recent

attoo performed with unsterile equipment. Because the differential diagnoses included Wilms tumor, he underwentpen exploration and nephrectomy. The histopathologic findings were consistent with xanthogranulomatous pyelo-ephritis, and cultures grew methicillin-resistant Staphylococcus aureus. The etiology was believed to be bacterial

eeding from the unsterile tattoo. UROLOGY 76: 1472–1474, 2010. © 2010 Elsevier Inc.

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anthogranulomatous pyelonephritis (XGP) is anunusual variant of chronic pyelonephritis charac-terized by parenchymal destruction and replace-

ent with granulomatous tissue containing lipid-ladenacrophages.1,2 It most commonly occurs in the fourth

o fifth decades of age but has been reported in caseeports and small case series in children.1,3,4 The preop-rative diagnosis can be difficult owing to the nonspecificlinical symptoms and radiologic similarities to malig-ancy.1,3,4

The most common predisposing factor is obstruction,ften from nephrolithiasis.3-5 Proteus and Escherichia coli arehe most common organisms associated with XGP.5,6 Weeport the case of a 16-year-old boy with nonspecific symp-oms and imaging findings consistent with either abscess oralignancy. Histopathologic examination confirmed the

iagnosis of XGP, and subsequent cultures revealed methi-illin-resistant Staphylococcus aureus (MRSA). An unsterileattoo was thought to be the etiology for his disease.

XGP should be a part of the differential diagnoses when-ver a renal mass is found. In the present patient, XGP wasow on the differential diagnosis. It is typically found inatients with risk factors, such as diabetes, hyperlipidemia,ntreated urinary tract infections, kidney stones, or immu-osuppression. This healthy adolescent boy had no medicalroblems, stones, or obstruction, and his initial culturesere negative.

ASE REPORT16-year-old boy initially presented to an outside hos-

ital with abdominal pain and fever of 3 weeks’ duration.

rom the Department of Urology, Connecticut Children’s Medical Center, Hartford,onnecticut; Department of Urology, Rady Children’s Hospital, University of Cali-

ornia, San Diego.Reprint requests: Christina Kim, M.D., Department of Urology, Connecticut Chil-

ren’s Medical Center, 282 Washington Street, Hartford, CT 06106. E-mail:

akim@ccmckids.org

Submitted: November 1, 2009, received (with revisions): March 31, 2010

472 © 2010 Elsevier Inc.All Rights Reserved

n ultrasound scan revealed a cystic lesion in his leftidney (Fig. 1), prompting his transfer to our Children’sospital. The patient complained of left-sided abdominal

ain and had a temperature of 104°F. He had no consti-utional symptoms. He denied dysuria or gross hematuria.is primary care physician had prescribed ciprofloxacin 1eek before presentation. He had no history of nephro-

ithiasis or urinary tract infections. He denied any elicitrug use. The cultures by his primary physician wereegative for bacterial growth. However, the cultures hadeen obtained after he started taking antibiotics.On examination, the patient appeared pale and un-

omfortable. His temperature was 140°F with a bloodressure of 110/60 mm Hg. He voided clear yellow urine,nd his abdomen was tender with costovertebral tender-ess. He was noted to have a 4-cm tattoo on his arm withild surrounding erythema. It had been applied at home

pproximately 3 weeks before presentation.The laboratory evaluation revealed a leukocytosis of 18

00/mm3, and his urinalysis findings were negative foritrite and leukocyte esterase. The results of subsequentlood and urine cultures were negative. Testing for hu-an immunodeficiency virus was negative. Computed

omography demonstrated a complex, cystic appearingtructure in the upper portion of the left kidney (Fig. 2).e was given broad-spectrum antibiotics, including clin-

amycin, vancomycin, and ceftazidime. Despite the an-ibiotics, he continued to have daily temperature spikes.

The differential diagnosis was of an infectious processersus malignancy. The more likely diagnosis was infec-ion, given the kidney’s changing appearance and theersistent fever. The patient was taken to the operatingoom for exploration by way of a transperitoneal trans-erse incision. The colon was adherent to the kidney butas dissected free. The kidney was inflamed, with multi-le purulent pockets. Owing to the diffuse microabscesses

nd friable nature of the tissue, the kidney was not

0090-4295/10/$36.00doi:10.1016/j.urology.2010.03.076

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menable to partial nephrectomy, and simple nephrec-omy was performed.

The final pathologic diagnosis was XGP (Fig. 3), andhe tissue culture grew MRSA. The patient recoverednd was discharged to home on postoperative day 10 with2-week course of trimethoprim-sulfamethoxazole.

OMMENTGP is an unusual form of chronic inflammatory diseaseot classically found in the pediatric population. In chil-ren, the condition occurs most frequently in those �8ears old without calculus involvement,5,7 although it

Figure 1. Ultrasound scan demonstrating cystic lesion.

igure 2. Computed tomography scan showing cystic ap-earing left kidney.

as been found in all age ranges. t

ROLOGY 76 (6), 2010

The symptoms are typically nonspecific and includeever, malaise, abdominal pain, and, less commonly, flankass. Urinary symptoms can include dysuria, frequency,

nd hematuria. Fewer than one half of patients will haveypertension on presentation.8

The etiology of XGP in the adult population is mostften urinary tract obstruction from nephrolithiasis.9

ther causes of obstruction include ureteropelvic junc-ion obstruction and vesicoureteral reflux.9 E. coli androteus are the most frequently implicated organisms.egative urine culture findings are most likely explained

y antibiotic treatment before culture.Our case was unusual in that the renal tissue culture

rew MRSA despite negative culture results and no evi-ence of nephrolithiasis or obstruction. Our hypothesisas that the recent, unsterile tattoo caused a bacteremia

hat seeded the affected kidney. Outbreaks of MRSAnfection or colonization have been shown to occur pe-iodically in tattoo recipients.10 To our knowledge, theathophysiology of bacterial seeding after a tattoo as aause of XGP has not been previously described. Ouratient had no history of nephrolithiasis or congenitalbnormalities. He had no pre-existing conditions thatould have predisposed him to an immunocompromised

tate.The laboratory evaluation will usually confirm leuko-

ytosis and might reveal elevated C-reactive protein,rythrocyte sedimentation rate, or liver enzymes. Therinalysis will show pyuria and hematuria.Radiologic evaluation of XGP can be challenging,

ecause it often resembles renal malignancy. Calculi areoted in approximately 75% of patients11 and can aid inhe diagnosis owing to the association with XGP. Nu-lear medicine scans might be helpful by estimating thendividual kidney function and detecting a mass. Theltrasound findings include an increased renal size fromeplacement of normal parenchyma with a fluid-filled orolid-appearing mass and might show acoustic shadowingrom a renal stone.

Some believe that computed tomography is the mostelpful imaging study for identifying XGP. Computedomography might show a classic “bear paw sign” fromilated caliceal spaces. Perinephric extension of the in-ammatory process can progress to an abscess and couldead to fistula formation.12 Our patient did not have aear paw appearance on computed tomography but in-tead had a complex cystic mass.

Magnetic resonance imaging can be useful in detectingn abscess and will accurately identify an enlarged, mul-iloculated kidney. Regardless of the modality, establish-ng the diagnosis can be challenging because no singlelinical or radiographic feature is unique to XGP. Theifferential diagnosis should include Wilms tumor, renalell carcinoma, mesoblastic nephroma, abscess. and cys-ic renal disease. The possibility of malignancy is a rela-ive contraindication to needle biopsy. Serial urine cy-

ology for foam cells has been used to preoperatively

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iagnose XGP, with an accuracy of 80%.13 Despite theseests, surgical exploration remains the definitive methodf confirming the diagnosis.Total nephrectomy is the reference standard treatment

f XGP. The standard approach for renal cancer in chil-ren is open surgery. Laparoscopy has been limited pri-arily to biopsies, small neuroblastomas, and benign

enal tumors. Although some case series have shownuccess with laparoscopic nephrectomy for Wilms tumor,t is not the standard surgical approach.14 Therefore, wehose an open approach for our patient. Surgery can behallenging because the kidney will be inflamed anddherent to the surrounding viscera. Percutaneous drain-ge and adjunctive antibiotics before surgical interven-ion are recommended to minimize perioperative compli-ations.5 The prognosis after surgery has been excellent,ith reports of late complications that have includedypertension, bacteriuria, and renal amyloidosis.15

ONCLUSIONSGP should be considered in the differential diagnosis ofpediatric patient presenting with a renal mass, even in

he absence of renal calculi and sterile urine. Failure toecognize the condition could lead to a prolonged illnessithout definitive treatment. The unique aspects of theresent case included an atypical presentation on imag-ng. In addition, the tissue culture growth of MRSA wastypical. Finally, the etiology of an unsterile tattoo hasot been previously reported.

eferences1. Brown PS, Dodson M, Weintrub PS. Xanthrogranulomatous pye-

lonephritis: report of nonsurgical management of a case and review

Figure 3. Pattern of lipid-laden histiocytes

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2. Hammadeh MY, Nicholls F, Calder CJ, et al. Xanthogranuloma-tous pyelonephritis in childhood: preoperative diagnosis is possible.Br J Urol. 1994;73:83-86.

3. Matthews GJ, McLorie GA, Churchill BA, et al. Xanthogranulo-matous pyelonephritis in pediatric patients. J Urol. 1995;153:1958-1959.

4. Rodo J, Martin ME, Salarich J. Xanthogranulomatous pyelonephri-tis in children: conservative management. Eur Urol. 1996;30:498-501.

5. Bingöl-Kologlu M, Ciftçi AO, Senocak ME, et al. Xanthogranulo-matous pyelonephritis in children: diagnostic and therapeutic as-pects. Eur J Pediatr Surg. 2002;12:42-48.

6. Tolia BM, Iloreta A, Freed SZ, et al. Xanthogranulomatous pyelo-nephritis: detailed analysis of 29 cases and a brief discussion ofatypical presentations. J Urol. 1981;126:437-442.

7. Braun G, Moussali L, Balanzar JL. Xanthogranulomatous pyelone-phritis in children. J Urol. 1985;133:236-239.

8. Levy M, Baual R, Eddy AA. Xanthogranulomatous pyelonephritisin children. Etiology, pathogenesis, clinical and radiologic featuresand management. Clin Pediatr. 1994;33:360-366.

9. Zafranloo S, Gerard PS, Bryk D. Xanthogranulomatous pyelone-phritis in children: analysis by diagnosis modalities. Urol Radiol.1990;12:18-21.

0. Centers for Disease Control and Prevention. Methicillin-resistantStaphylococcus aureus skin infections among tattoo recipients—Ohio, Kentucky, and Vermont, 2004-2005. MMWR Morb MortalWkly Rep. 2006;55:677-679.

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2. Pearsons MA, Harris SC, Grainger RG, et al. Fistula and sinusformation in xanthogranulomatous pyelonephritis: a clinicopatho-logical review and report of four cases. Br J Urol. 1986:488-493.

3. Ballasteros JJ, Serrano S, Faus R, et al. Urinary cytology in thediagnosis of renal xanthogranulomatous pyelonephritis. Eur Urol.1983;9:343-345.

4. Duarte RJ, Dénes FT, Cristofani LM, et al. Laparoscopic nephrec-tomy for Wilms’ tumor. Expert Rev Anticancer Ther. 2009;9:753-761.

5. Chang JW, Chen SJ, Chin TW, et al. Xanthogranulomatous pye-lonephritis treated by partial nephrectomy. Pediatr Nephrol. 2004;

cteristic of XGP in 10� and 40� images.

19:1164-1165.

UROLOGY 76 (6), 2010