[Xanthogranulomatous pyelonephritis in an adolescent].

Area of Science:

• Nephrology
• Pathology
• Radiology

Background:

• Xanthogranulomatous pyelonephritis (XGP) is a rare, chronic destructive inflammation of the kidney, often mimicking a renal tumor.
• It predominantly affects elderly women (over 60 years) and is frequently associated with Escherichia coli or Proteus mirabilis infections.

Observation:

• This report details an unusual case of XGP in a male adolescent involving the right kidney.
• The patient presented with a normally functioning kidney and no prior pathological history, making the diagnosis challenging.
• The presentation deviated significantly from typical XGP demographics and clinical features.

Findings:

• Microbiological cultures frequently show bacterial growth (urine >50%, renal tissue >90%), commonly E. coli or P. mirabilis.
• Common radiographic and clinical findings include malnutrition, calcification, urolithiasis, renal failure, and hydronephrosis.
• The left kidney is more commonly affected in reported cases.

Implications:

• This case underscores the importance of considering atypical presentations of XGP, particularly in younger patients.
• The unclear etiology, with hypotheses including malnutrition and peroxidase deficiency, warrants further investigation.
• Understanding these unique characteristics may improve diagnostic accuracy and management strategies for XGP.