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Pseudotumoral and focal xanthogranulomatous pyelonephritis: diagnostic difficulties and efficiency of the conservative treatment

M. Gasmi, F. Fitouri, R. Jemaï, N. Sghaïroun, A. Essid, S. Sahli, M. Hamzaoui.

Department of Pediatric Surgery, Pediatric Hospital, Tunis, Tunisia



Introduction: Xantogranulomatous pyelonephritis is a rare chronic infection of the kidney, characterized by the presence of a foamy histiocytic proliferation. The symptoms are not specific, making the diagnosis difficult, frequently made postoperatively. The etiopathogenesis is obscure and the treatment is not defined.

Material and methods: The authors report a pseudotumoral focal type of xantogranulomatous pyelonephritis; they specify the importance of the imaging and discuss the therapeutic methods. A 2 year old boy was admitted for a voluminous and painful mass of the right flank with fever evolving for 15 days. The blood analyses showed hyperleucocytosis (12.800 per mm3) and an elevated C-reactive protein (50 milligrams per litre). The urine bacteriological analyses was negative. Ultrasonography showed an anechoic formation located on the lower pole of the right kidney, measuring 80 millimetres in diameter, without calcifications or urinary lithiasis. The tomodensitometry showed that the mass was multiloculated with peripheral contrast enhancement and with a perirenal thickening. The left kidney was normal. The tumoral or inflammatory origin could not be specified, justifying a surgical exploration.

Results: By a pararectal approach, they discovered a voluminous abscess located on the lower pole of the right kidney, having intimate adherences with the neighbouring structures. A biopsy with evacuation of the collection, toilet and drainage were performed. The histological examination made the diagnosis of xanthogranulomatous pyelonephritis. The preoperative collection sample was positive for Escherichia Coli. An adapted antibiotherapy allowed the complete and progressive regression of the lesion and the conservation of the kidney. The follow-up at 15 month is without relapse.

Conclusion: The diagnosis of xanthogranulomatous pyelonephritis must not be overlooked in case of lumbar mass with fever. The imaging by magnetic resonance seems to be more contributory. The medical treatment can be curative and is recommended in case of focal xanthogranulomatous pyelonephritis of the child.


Key words: xantogranulomatous pyelonephritis, biopsy, Escherichia Coli