Learning objectives
The aim of this study is to:
· present an extremely rare condition in paediatrics -
xanthogranulomatous pyelonephritis (XP)
· illustrate its two variants
· review possible imaging techniques used and their findings
· suggest other diseases to differentiate XP with
· encourage radiologists and clinicists to include XP in
differential diagnosis.
Background
Xanthogranulomatous pyelonephritis,
or XP in short,
is a rare form of chronic renal infection,
making up around 1% of all chronic pyelonephritis.
Even more so in paediatric population,
as patients with this disease are usually between 50 and 70 years old,
with women said to be affected up to 4 times more often.
The core of XP are slow but progressive changes that include destruction of renal parenchyma,
which is then replaced with lipid-filled macrophages.
It is believed to be a response to recurring subacute...
Findings and procedure details
The process can affect whole kidney and extend to surrounding tissue,
which then is known as diffuse form XP.
This type is the most common,
comprising up to 90% of cases,
and at the same time boasts the most characteristic imaging findings:
· Computed tomography:
It is considered a gold-standard in imaging of XP.
At least 2-phase exam is performed with the use of intravenous contrast.
First visible change is kidney enlargement,
with the shape staying intact.
Often a hydronephrosis-like transformation is seen,
caused by...
Conclusion
· Despite its rarity,
xanthogranulomatous pyelonephritis needs to be taken into account in cases of children with renal masses.
· Even though CT is the method of choice,
other techniques remain relevant,
with MRI having a similar diagnostic yield compared to tomography.
· Cases of focal XP and atypical history require high awareness and are often diagnosed histopathologically after surgery.
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