Case report: Xanthogranulomutous pyelonephritis presenting as “Wilms’ tumor”

Abstract

Background: Xanthogranulomatous pyelonephritis (XGP) is a rare renal tumor that arises as a complication of chronic

obstructive pyelonephritis of uncertain etiology. It is primarily an adult tumor seen occasionally in children associated with

urinary tract obstruction due to congenital urological anomalies, nephrolithiasis, and recurrent urinary tract infections.

Radiologically, it may show neoplastic features such as those seen in common pediatric renal malignancies like wilms’

tumor and renal cell carcinoma. This overlap in radiological manifestation frequently leads to misdiagnosis and delay in

appropriate intervention. We report a case of a 3 years old boy who presented with history of recurrent urinary tract

infections and a left renal mass initially thought to be Wilms’ tumor.

Case presentation: We present a case of a 3 years old boy admitted to the Pediatric oncology unit at Muhimbli National

Hospital in Dar es Salaam, Tanzania with one year history of recurrent fever and urinary tract infection signs and

symptoms refractory to antibiotic therapy. He was eventually found to have a left kidney mass detected at the District

hospital by abdominal ultrasound performed to evaluate a flank mass that was felt by his mother. He was then referred

to our unit for a suspicion of Wilms’ tumor which finally turned out to be a left kidney Xanthogranulomatous

pyelonephritis.

He underwent a successful left nephrectomy and was discharged from hospital in a stable clinical condition and remains

asymptomatic at the time of submission of this case report.

Conclusion: This case report underscores the need for clinicians attending a febrile child with a renal mass

that can be confused with common pediatric renal malignancies such as Wilms’ tumor to broaden their

differential diagnosis. The case also underlines the significance of individualized patient evaluation because

this patient would have otherwise received preoperative chemotherapy under the International Society of

Pediatric Oncology (SIOP) guidelines if the diagnosis of Wilms tumor was not ruled out.