Imaging Pearls ❯ Kidney ❯ Retriperitoneal Fibrosis
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- “Retroperitoneal fibrosis represents fibro-inflammatory soft tissue plaque in the retroperitoneal space that often encases the aorta and one or both ureters resulting in obstruction . RPF is idiopathic in majority of the cases and has been associated with malignancy, autoimmune inflammatory disorders, GVHD, drugs, surgery, and multiple sclerosis in small number of cases . RPF usually affects males in their 4th–6th decades of life and often presents with non-specific symptoms such as malaise, anorexia, and chronic backache. RPF is predominantly benign with a favorable prognosis. Small number cases, up to 8%, have been reported as malignant RPF with a poor prognosis and typical 3–6 months survival. Retroperitoneal fibrosis represents fibro-inflammatory soft tissue plaque in the retroperitoneal space that often encases the aorta and one or both ureters resulting in obstruction.”
Imaging of ureter: a primer for the emergency radiologist
Mohd Zahid et al.
Emerg Radiol (2021). https://doi.org/10.1007/s10140-021-01930-5 - “Retroperitoneal fibrosis represents fibro-inflammatory soft tissue plaque in the retroperitoneal space that often encases the aorta and one or both ureters resulting in obstruction . RPF is idiopathic in majority of the cases and has been associated with malignancy, autoimmune inflammatory disorders, GVHD, drugs, surgery, and multiple sclerosis in small number of cases . RPF usually affects males in their 4th–6th decades of life and often presents with non-specific symptoms such as malaise, anorexia, and chronic backache. RPF is predominantly benign with a favorable prognosis. Small number cases, up to 8%, have been reported as malignant RPF with a poor prognosis and typical 3–6 months survival.”
Imaging of ureter: a primer for the emergency radiologist
Mohd Zahid et al.
Emerg Radiol (2021). https://doi.org/10.1007/s10140-021-01930-5 - "CT urography reveals medial deviation and smooth narrowing of the middle one-third of one or both ureters in the lower lumbar or upper sacral region. There are variable degrees of proximal hydroureteronephrosis and delayed renal excretory function due to increased pressure. CT helps to assess the location and extent of RPF and its effect on the adjacent vascular and visceral structures. RPF may look like retroperitoneal soft tissue rind or fibrotic plaque that obliterates the periureteral and aortocaval fat planes. The important distinguishing feature of benign RPF from malignant RPF, lymphoma, and metastatic lymph nodes is that the fibrotic plaque may extend behind the aorta and anterior to the spine but rarely displaces the aorta anteriorly, although it has poor sensitivity and specificity.”
Imaging of ureter: a primer for the emergency radiologist
Mohd Zahid et al.
Emerg Radiol (2021). https://doi.org/10.1007/s10140-021-01930-5 - "Degree of enhancement of benign RPF on CT correlates with fibrotic activity, avid enhancement suggests active phase, and minimal to no enhancement seen in avascular chronic plaque. Variable enhancement pattern is also seen in malignant RPF. There is significant overlap between benign RPF and malignant RPF in imaging morphology and enhancement patterns. RPF should be considered as malignant in a known abdominal primary malignancy with concomitant retroperitoneal lymph nodes. Approximately one-third surgically proven cases may have normal CT findings.”
Imaging of ureter: a primer for the emergency radiologist
Mohd Zahid et al.
Emerg Radiol (2021). https://doi.org/10.1007/s10140-021-01930-5 - "Genitourinary tuberculosis is the second most common form of extrapulmonary tuberculosis and usually caused by hematogenous dissemination. It accounts for 15–20% of all extrapulmonary tuberculosis cases. Genitourinary tuberculosis involves the ureter in approximately 50% of the cases. In early disease, IVU or retrograde urography shows ragged and dilated ureter and occasional filling defects of mucosal granulomas . CT urography demonstrates ureteral mural thickening with periureteral inflammatory changes. Tuberculosis tends to involve distal third of the ureter and causes multiple strictures and fibrotic changes with disease progression resulting in a characteristic “beaded or corkscrew” appearance . Chronic mural thickening of the ureter results in foreshortening and “pipestem” ureter. Tuberculosis may also present as pseudotumor due to inflammatory ureteral mural thickening and would be difficult to distinguish from malignancy on imaging . In a small number of cases, ureteral calcifications can be seen.”
Imaging of ureter: a primer for the emergency radiologist
Mohd Zahid et al.
Emerg Radiol (2021). https://doi.org/10.1007/s10140-021-01930-5
- Extramedullary Hematopoeisis: Common Causes
- myelofibrosis
- diffuse osseous metastatic disease replacing the bone marrow
- leukaemia
- sickle cell disease
- thalassemia. - Infiltration of the Perinephric Space: Differential Diagnosis
- Retroperitoneal fibrosis
- Erdheim-Chester disease
- Lymphoma
- Extramedullary hematopoiesis
- Liposarcoma
- Metastases (melanoma is classic)
- Hematoma (often post trauma or biopsy)