MyPACS.net: Radiology Teaching Files > Case 17484372

Never visited RETROPERITONEAL FIBROSIS
Contributed by: Jake Naidu, Resident, John Peter Smith Hospital, Texas, USA.
Patient: 55 year old
History:

55 y/o female presented to the ER because of the
complaints of abdominal pain, flank pain, vomiting, and diarrhea for 2 weeks.

Images:[small]larger

Fig. 1: Bilateral severe hydronephrosis with a soft tissue mass encasing the aorta. This soft tissue extends into the iliac regions. The ureters are lost in the conglomerate mass. B/L perinephric fat stranding worse on the right.

Fig. 2: Bilateral severe hydronephrosis with a soft tissue mass encasing the aorta. This soft tissue extends into the iliac regions. The ureters are lost in the conglomerate mass. B/L perinephric fat stranding worse on the right.

Fig. 3: Bilateral severe hydronephrosis with a soft tissue mass encasing the aorta. This soft tissue extends into the iliac regions. The ureters are lost in the conglomerate mass. B/L perinephric fat stranding worse on the right.

Fig. 4: Bilateral severe hydronephrosis with a soft tissue mass encasing the aorta. This soft tissue extends into the iliac regions. The ureters are lost in the conglomerate mass. B/L perinephric fat stranding worse on the right.

Fig. 5: Bilateral severe hydronephrosis with a soft tissue mass encasing the aorta. This soft tissue extends into the iliac regions. The ureters are lost in the conglomerate mass. B/L perinephric fat stranding worse on the right.

Fig. 6: Bilateral severe hydronephrosis with a soft tissue mass encasing the aorta. This soft tissue extends into the iliac regions. The ureters are lost in the conglomerate mass. B/L perinephric fat stranding worse on the right.

Fig. 7: Post nephrostomy tube placement and nephrostogram reveals abnormal tapering of the ureters more prominent on the right at about L4. Hydronephrosis present on Right.

Fig. 8: Retroperitoneal fibrosis is made up of fibrous tissue (pink background) with inflammatory cells like plasma cells, benign lymphocytes and eosinophils. The white open spaces are entrapped fat cells. The lower portion of the slide shows a heavier concentration of inflammation.

Fig. 9: Retroperitoneal fibrosis is made up of fibrous tissue (pink background) with inflammatory cells like plasma cells, benign lymphocytes and eosinophils. The white open spaces are entrapped fat cells.

Fig. 10: Retroperitoneal fibrosis is made up of fibrous tissue (pink background) with inflammatory cells like plasma cells, benign lymphocytes and eosinophils. The white open spaces are entrapped fat cells.

Fig. 11: Ultrasound shows severe hydronephrosis.
Findings:

ABDOMEN: She has discomfort in both anterior abdomen and the bilateral costovertebral area.
BUN 17/Creatinine 1.9.


CT abdomen: Bilateral severe hydronephrosis with an soft tissue mass encasing the aorta. This soft tissue extends into
the iliac regions. The ureters are lost in the conglomerate mass. B/L perinephric fat stranding worse on the right.

Nephrostogram revealed abnormal tapering of the ureters more prominent on the Right at about L4 level. Hydronephrosis is present on the Right. Percutaneous nephrostomy tubes places.

Biopsy results: Benign fibrous tissue (pink background) with inflammatory cells like plasma cells, benign lymphocytes and eosinophils. The white open spaces are entrapped fat cells.

Diagnosis: Retroperitoneal Fibrosis
Discussion:

Definition: Retroperitoneal Fibrosis (RPF) is a chronic inflammatory process of the lumbar retroperitoneal region.This fibrosis eventually leads to entrapment and obstruction of retroperitoneal structures, especially the ureters.

Age: usually above 40 years

Frequency: ~1 per 200,000-500,000 population

Male to female ratio is 2 to 1.

Complications: Extrinsic ureteral obstruction leading to renal failure
Aorta and or inferior vena cava obstruction

Prognosis: Good; may require surgery

Clinical symptoms: Most commonly back pain, flank pain, abdominal pain. Renal insufficiency, hypertension, leg edema, anemia.

Causes: Mostly Idiopathic. Other factors include:
•Malignancy
•Inflammatory periaortitis (severe atherosclerosis)
•Chronic retroperitoneal inflammation
•Retroperitoneal trauma
•Autoimmune disease
•Radiation
•Drugs such as beta-blockers, methysergide, methyldopa


Differential diagnosis:
Retroperitoneal metastasis
Lymphoma
AAA
Retroperitoneal hemorrhage

Histology:
Early stage: Inflammatory infiltrate containing macrophages, lymphocytes, plasma cells, and occasional eosinophils.

Chronic stage, the tissue becomes avascular and acellular with scattered calcification and progresses to fibrous scarring.

Malignant retroperitoneal fibrosis demonstrates the presence of scattered nests of malignant cells within the inflammatory tissue.


Features:
Soft tissue mass encasing the aorta, inferior vena cava, and the ureters. Location is usually in the lower lumbar region with extension into the pelvis.

In its acute stage retroperitoneal fibrosis can present as a focal unilateral mass in the region of the common iliac vessels. As the disease progresses, fibrosis extends superiorly into the retroperitoneum along the major vessels.

Distinguishing feature between retroperitoneal fibrosis from retroperitoneal lymphadenopathy and lymphoma since that the fibrous tissue envelopes the aorta, IVC, and the ureters but does not displace the aorta anteriorly substantially.

Malignant retroperitoneal fibrosis is most commonly associated with cervical, breast, prostate, bowel, lung, and kidney cancers. The contour of the mass is not lobular distinguishing it from lymphadenopathy. The mass is infiltrative and irregular. The distinction between acute benign retroperitoneal fibrosis and a malignant retroperitoneal fibrosis is difficult. Findings that favor malignancy include a more irregular contour and increased in size and irregularity on follow-up examination. Acute benign RPF has a wispy infiltrative pattern compared to malignant disease which is more solid and the regular. Benign RPF is seen in a population with no pre existing malignant condition. Malignant retroperitoneal fibrosis is more commonly seen in older patients > 40 years of age.


Radiological Findings:

IVP Findings: Hydronephrosis with proximal ureteral dilation above L4-L5. There is medial deviation of the ureters bilaterally. Gradual tapering of the ureters secondary to extrinsic compression.

CT findings: Soft tissue density of variable thickness that may extend from the crus of the diaphragm to the common iliac vessels.
This soft tissue density is most commonly seen extending from the renal hilum to the pelvic brim but may rarely involve the kidneys, pancreas, mediastinum, and the spleen.
The soft tissue mass usually surrounds the aorta, IVC, and the ureters bilaterally. There may be displacement/compression/narrowing of these structures.
Contrast-enhanced CT: Increased enhancement suggests active inflammatory process whereas decreased enhancement suggests organized fibroids tissue.

MR findings:
T1WI: Low homogeneous signal intensity
T2WI: Low to moderate heterogeneous signal intensity

Ultrasound findings:
Irregular periaortic soft tissue mass.

Treatment:
Steroids, Tamoxifen
Surgical: Ureteral Stenting, Ureterolysis

Prognosis:
Good but may require surgery

References:

Semelka, Abdominal-Pelvic MRI. Retroperitoneal masses. 1097-1125, 2006.

Federle, Diagnostic imaging Abdomen. Retroperitoneal fibrosis. 3110-3113, 2005.


Chandra Shekhar, E-medicine. Retorperitoneal Fibrosis. 2006.

Comments:
Great case and great overview. Much appreciated--Peter Kohout, 2010-05-11
thank you. A good case and really helpful discussion.--Najeeb Ahmed, 2012-04-09
Additional Details:

Case Number: 17484372Last Updated: 2011-08-05
Anatomy: Genitourinary (GU)   Pathology: Benign Mass, Cyst
Modality: CT, GU, US, PathologyAccess Level: Readable by all users

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