Community-associated methicillin-resistant Staphylococcus aureus causing diffuse xanthogranulomatous pyelonephritis in a neonate

• XPG is uncommon in children and extremely rare in neonates and infants.
• Methicillin-resistant Staphylococcus aureus is an exceptionally rare cause of XPG.
• Radiological diagnosis of XGP is challenging as the disease mimics neoplastic pathology.
• Clinical, radiological, pathological and microbiological correlation is essential for accurate diagnosis.
• XGP should be considered in neonates with fever, flank mass and hematuria even if blood and urine cultures are negative.

Xanthogranulomatous pyelonephritis (XGP) is an uncommon variant of chronic pyelonephritis; often associated with ipsilateral urological obstructive pathology and infection. It occurs rarely in the pediatric population and is caused usually by gram-negative bacteria. We herein present a case of a 6-week old male patient who presented with fever, gross hematuria and left flank tenderness. Urine and blood cultures were negative. Radiological investigations suggested an infiltrating malignant neoplasm of the kidney. There was no evidence of nephrolithiasis or obstructive pathology. A left radical nephrectomy was performed and histopathological examination revealed diffuse XGP. Microbiological culture of the perinephric purulent discharge proved positive for methicillin-resistant Staphylococcus aureus (MRSA). To the best of our knowledge, this is the first reported case of MRSA-induced XGP in a neonate emphasizing the expanding spectrum of disease secondary to community-associated MRSA.