An unusual manifestation of xanthogranulomatous pyelonephritis: bilateral focal solid renal masses

A pediatric case of xanthogranulomatous pyelonephritis in the setting of Covid-19 and multi-system inflammatory syndrome (MIS-C)

Xanthogranulmatous pyelonephritis is a rare, chronic inflammatory pathology of the kidney. It most commonly arises in middle-aged females, but there are case reports and series described in the pediatric population. Here, we discuss the case of a 14 year old male who presented with xanthogranulomatous pyelonephritis in the setting of Covid-19 and multi-system inflammatory syndrome (MIS-C). As xanthogranulomatous pyelonephritis often mimics other diseases that are more prevalent in the pediatric population, our case was only definitively diagnosed with histopathology after surgical resection. This report is novel in that, to our knowledge, it is the first to describe xanthogranulomatous pyelonephritis in the setting of MIS-C.

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Nous présentons l’observation clinique d’un cas rare de pyélonéphrite xanthogranulomateuse (PXG) bilatérale chez un jeune patient âgé de 17 ans. La découverte progressive de l’infection a débuté par l’apparition de lombalgies bilatérales évoluant depuis un mois, sans autre signe associé. L’urotomodensitométrie penchait en faveur de deux masses rénales bilatérales, soit une masse polaire inférieure droite et une masse polaire supérieure gauche, toutes deux de densité tissulaire. Une biopsie écho guidée a suggéré la présence d’une réaction inflammatoire non spécifique. Une néphrectomie partielle polaire inférieure droite a été effectuée devant la forte présomption de tumeurs rénales malignes. Finalement, l’histologie a orienté le diagnostic vers une PXG. Il s’agit, à notre connaissance, du sixième cas de PXG focale bilatérale rapporté dans la littérature. Notre patient a reçu un traitement antibiotique à base de fluoroquinolone pendant un mois. L’évolution clinique s’est avérée bonne, et les lésions visibles à la tomodensitométrie se sont entièrement résorbées au bout d’un mois. Le patient vit toujours après un an et présente une fonction rénale normale.

Bilateral xanthogranulomatous pyelonephritis

Xanthogranulomatous pyelonephritis is an uncommon form of chronic bacterial pyelonephritis characterized by the destruction of renal parenchyma and the presence of granulomas, abscesses, and collections of lipid-laden macrophages (foam cells) replacing the renal parenchyma. This case report illustrates the clinical course of bilateral diffuse xanthogranulomatous pyelonephritis with a subtle manifestation in contrast to those typically presenting with fever, flank pain or urinary tract infection. The patient therefore received supportive treatment for 18 months without hemodialysis, instead of the curative treatment, bilateral nephrectomy, which would have caused immediate loss of residual renal function and dependence on hemodialysis.

Xanthogranulomatous pyelonephritis with nephrocutanous fistula and coexisting renal replacement lipomatosis

Renal replacement lipomatosis (RRL) is the result of rare, usually unilateral, and severe atrophy and destruction of the renal parenchyma often caused by renal calculi. It may be associated with, sometimes, aging, atrophy, long-standing chronic inflammation and urinary infection, such as renal tuberculosis. We report magnetic resonance (MR) and computed tomography (CT) findings of our case, which has xanthogranulomatous pyelonephritis (XGP) and RRL additionally associated with nephrocutanous fistula.

Pediatric focal xanthogranulomatous pyelonephritis: dynamic contrast-enhanced MRI findings

Xanthogranulomatous pyelonephritis (XPN) is the result of chronic renal infection. It is very rare in childhood and the focal form, which is said to be more common in children, is often misdiagnosed as a renal tumor. We report a case of a focal XPN in a 14-year-old girl. The true preoperative diagnosis may be very hard in children especially in the focal form but it seems to be possible by the help of dynamic contrast-enhanced MRI.

US and CT findings of xanthogranulomatous pyelonephritis

Ultrasonographic and computed tomographic findings of 21 cases of pathologically proven xanthogranulomatous pyelonephritis (XGP) in 20 patients were retrospectively evaluated. Seventeen (81%) were diffuse, and extrarenal extension occurred in 13 cases (62%). The kidney was enlarged diffusely in 12 cases (57%), and focally in 3 (14%). Urinary calculi were present in 16 cases (76%), with staghorn calculi in 4 of these, and hydronephrosis occurred in 17 (81%). In addition to typical features of XGP, the condition may also show variable imaging findings.