Retroperitonealfibrose nach EVAR

Retroperitoneal
fibrosis in a patient with an endovascular aneurysm repair. Abdominal ultrasound shows an aortic aneurysm with an EVAR and diffuse calcification of the aorta wall. A homogeneously hypoechoic band with irregular margins is seen enfolding the aorta, along the extension of the aneurysm.
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Retroperitoneal
fibrosis in a patient with an endovascular aneurysm repair. Abdominal ultrasound shows an aortic aneurysm with an EVAR and diffuse calcification of the aorta wall. A homogeneously hypoechoic band with irregular margins is seen enfolding the aorta, along the extension of the aneurysm.
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Retroperitoneal
fibrosis in a patient with an endovascular aneurysm repair. CT shows the aortic aneurysm with an EVAR and a homogeneous and well-defined mass with irregular borders and spontaneous attenuation similar to the paraspinal muscles, wrapping the aorta anteriorly and laterally.
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Retroperitoneal
fibrosis in a patient with an endovascular aneurysm repair. Arterial phase CT shows preserved EVAR permeability and no signs of endoleak. The mass appears infiltrative, without mass effect on the surrounding structures such as the arterial vessels seen anteriorly.
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Retroperitoneal
fibrosis in a patient with an endovascular aneurysm repair. Portal phase CT shows mild and homogeneous enhancement of the mass.
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Retroperitoneal
fibrosis in a patient with an endovascular aneurysm repair. The enhancement of the mass is homogeneous and progressive, peaking in the late phase CT.
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Retroperitoneal
fibrosis in a patient with an endovascular aneurysm repair. Arterial phase CT with coronal reformation.
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Retroperitoneal
fibrosis in a patient with an endovascular aneurysm repair. Portal phase CT with coronal reformation.
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Retroperitoneal
fibrosis in a patient with an endovascular aneurysm repair. Portal phase CT with sagittal reformation.
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Retroperitonealfibrose nach EVAR

retroperitoneale Fibrose allgemein Radiopaedia • CC-by-nc-sa 3.0 • de

Retroperitoneal fibrosis (RPF), is a condition that has previously been described as chronic periaortitis. It is an uncommon fibrotic reaction in the retroperitoneum that typically presents with ureteric obstruction.

The disease is part of a spectrum of entities that have a common pathogenic process consisting of an inflammatory response to advanced atherosclerosis of the abdominal aorta, combined with autoimmunologic factors:

Epidemiology

Retroperitoneal fibrosis is an uncommon condition with a reported estimated incidence of 1.38 cases per 100,000 people . The mean age is approximately 64 years with a male-to-female ratio of 3:1 .

Clinical Presentation 

They can present with systemic symptoms such as mild fever, malaise due to an ongoing inflammatory process. Some times they get flank or back pain which is not position-dependent and has a transient relief with oral non-steroidal anti-inflammatory drugs . If the ureters are involved, may develop a colicky ureteric pain.

Pathology

Etiology

Radiographic features

General principles

Contrast-enhancing fibrosis encasing the retroperitoneal structures causing ureteric and vascular obstruction and displacement.

Displacement of the aorta and IVC anteriorly away from the vertebral bodies are suggestive of malignant etiology. Invasion and disruption of bone and/or soft tissue structures suggests an aggressive process - infection or malignancy.  Multiple subcentimeter lymph nodes are frequently seen in non-malignant RPF, probably reactive secondary to the disease process, and should not be confused for malignancy .

Fluoroscopy: IVU

While largely superseded by cross-sectional imaging techniques, a classic triad is described :

  • medial deviation of the middle third of the ureters
  • tapering of the lumen of one or both ureters in the lower lumbar or upper sacral region
  • proximal unilateral or bilateral hydroureteronephrosis with delayed excretion of contrast material (reported in over half of cases and thought to be due to impaired peristalsis)
    • CT

    Retroperitoneal fibrosis is visible as a soft tissue density mass located around the aorta and iliac arteries. Classically, it develops around the aortic bifurcation and spreads upwards where it can envelop the renal hila. It encases but does not invade or stenose the ureters or vessels. However, ureteric obstruction and venous thromboses can occur.

    In early or active stages, variable enhancement can be seen with intravenous contrast while no enhancement may be seen in the quiescent disease.

    MRI

    MRI has been reported to be as sensitive as CT in its assessment of retroperitoneal fibrosis with the added advantage of high contrast resolution between closely apposed retroperitoneal structures. It can evaluate the urinary tracts using fast T2 weighted spin-echo sequences without requiring intravenous contrast in patients with impaired renal function.

    The soft tissue mass is usually dark on T1W and T2W unless there is an active inflammation whereby the T2W images can be hyperintense.

    FDG-PET

    Uptake will be seen in active inflammation and absent in metabolically inactive disease .

    Treatment and prognosis

    Retroperitoneal fibrosis may lead to ureteric obstruction and consequent renal failure. In some cases, a blow-out of the ureter is described as a result of the obstruction.

    Differential diagnosis

    Imaging differential considerations include:

    Siehe auch:
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