Mahmoud Hsairi, Achraf Saidi, Samia Amar, Rachida Saouab, Mohammed Ennmer
Journal: Medpeer Publisher
ISSN: 3066-2737
Volume: 3
Issue: 7
Date of Publication: 2026/07/18
Background: Xanthogranulomatous pyelonephritis (XGP) is a rare, severe chronic granulomatous inflammation characterized by the replacement of renal parenchyma with lipid-laden macrophages. It is typically associated with chronic obstructive uropathy and recurrent infections. While the disease is classically highly symptomatic—presenting with flank pain, fever, and systemic toxicity—its variable clinical spectrum can occasionally mask advanced retroperitoneal involvement. Case Presentation: We report a marked clinico-radiological discrepancy in a 40-year-old male who presented for a routine outpatient computed tomography (CT) urography following a resolved episode of right-sided renal colic. Despite being hemodynamically stable and completely asymptomatic at the time of the examination, cross-sectional imaging revealed advanced XGP. The imaging demonstrated a dense (700 HU) obstructing pelvic calculus causing marked right caliceal dilatation with severe parenchymal thinning. This was complicated by extensive contiguous spread breaching Gerota’s fascia, forming large loculated collections extending into the perinephric space, the right psoas muscle, and the adjacent erector spinae musculature. Conclusion: This case highlights the insidious pathogenesis of XGP. It underscores the critical role of CT imaging in staging the disease and identifying advanced extrarenal and musculoskeletal extension, even when the clinical presentation is deceptively benign.
Xanthogranulomatous pyelonephritis ,Computed tomography ,Nephrolithiasis ,Retroperitoneal abscess, Psoas muscle ,Extrarenal extension
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