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Retroperitoneal Fibrosis

The Clinical, Laboratory, and Radiographic Presentation

Scheel, Paul J. Jr MD; Feeley, Nancy CRNP

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doi: 10.1097/MD.0b013e3181afc439
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Abstract

INTRODUCTION

Retroperitoneal fibrosis (RPF) is an inflammatory-fibrosing disorder that affects the infrarenal great vessels and the surrounding retroperitoneal structures. It is a rare disease of unclear etiology that frequently presents a diagnostic dilemma. Recently, there has been an attempt to classify RPF into the group of diseases collectively called periaortitis.28 Included in this group would be the 3 disease states that lead to inflammation surrounding the infrarenal aorta, namely RPF, perianeurysmal fibrosis, and inflammatory abdominal aortic aneurysms. Most if not all of the clinical data assembled on these entities have been gathered from small retrospective series or collated case reports.2-4,10,15,24,29,31 Therapy varied from surgical ureterolysis to medical intervention including the use of various immunosuppressive/antifibrotic agents such as corticosteroids, mycophenolate mofetil, cyclosporine, cyclophosphamide, methotrexate, azathioprine, and chlorambucil.11,13,20,21,30 Many of these series contained a heterogeneous population from multiple different centers with varying forms of periaortitis. While few data are available on the pathogenesis of these 3 disorders, it is unlikely that they represent the same condition, thus adding to the confusion about available information on RPF. Additionally, most of these reports were retrospective reviews, few contained histologic confirmation, and not all described inclusion criteria.

We conducted the current study to describe the clinical, laboratory, and radiographic presentation of patients who were referred to the RPF clinic at the Johns Hopkins Hospital. All patients were seen by a single physician, data were collected in a prospective fashion, and the same diagnostic criteria were applied to all patients. To our knowledge this is the largest, most comprehensive report describing only patients with RPF while excluding patients with other forms of periaortitis. [Editor's note: See also the new report by van Bommel et al29a and Vaglio's commentary26a on these 2 large prospective studies of RPF in this same issue].

PATIENTS AND DEFINITIONS

Patients were considered to have RPF if they fulfilled the following criteria:

  • 1) soft-tissue density surrounding the infrarenal aorta or iliac vessels by contrast-enhanced computed tomography (CT) or magnetic resonance imaging (MRI);
  • 2) absence of aneurysmal dilation of the infrarenal aorta;
  • 3) absence of intraabdominal or pelvic mass by imaging aside from the periaortitis;
  • 4) lack of clinical suspicion of malignancy from history and physical exam;
  • 5) negative up-to-date, age-appropriate cancer screening as recommended by the American Cancer Society.22

All patients who did not meet these requirements underwent biopsy.

Laboratory Screening

All patients underwent initial assessment with complete blood count, renal function profile, erythrocyte sedimentation rate, testing for antinuclear antibodies (ANA), and assays for thyroid-stimulating hormone.

Imaging and Classification System

Abdominal cross-sectional imaging either by contrast-enhanced CT or MRI was reviewed by a single observer. Patients were classified based on the extent of the soft-tissue mass:

  • Class I: soft-tissue density surrounding the infrarenal aorta and/or iliac vessels (Figure 1).
  • Class II: soft-tissue density surrounding the infrarenal vena cava (Figure 2).
  • Class III: lateral extension of the inflammation/fibrosis with compression of 1 or both ureters (Figure 3).
  • Class IV: extension of fibrosis to include the renal hilum with compression of the renal artery and/or renal vein (Figure 4).
F1-2
FIGURE 1:
Class I RPF. CT scan of the abdomen with intravenous contrast. Small arrow indicates aorta and large arrow indicates soft tissue surrounding aorta.
F2-2
FIGURE 2:
Class II RPF. CT scan of the abdomen with intravenous contrast. Small arrow indicates soft-tissue density surrounding aorta (class I) and large arrow indicates soft-tissue density surrounding inferior vena cava (class II).
F3-2
FIGURE 3:
Class III RPF. CT scan of the abdomen with intravenous contrast. Small arrow indicates soft-tissue density extending from aorta and surrounding the ureter, which has an indwelling ureteral stent. Large arrow indicates aorta.
F4-2
FIGURE 4:
Class IV RPF. CT scan of the abdomen with intravenous contrast. Small arrow indicates soft-tissue density surrounding left renal vein. Large arrow indicates soft-tissue density surrounding the aorta.

Patients could be categorized in multiple classes based on extent of disease seen on imaging.

Pathologic specimens were reviewed using light microscopy. Depending on the suspicion of the attending pathologist, additional stains and alternate forms of microscopy were ordered on a per-case basis.

RESULTS

Between May 2003 and January 2009, 57 patients were referred to the RPF clinic at The Johns Hopkins Hospital. Forty-eight patients met the criteria for diagnosis. Three patients were excluded because of atypical soft tissue surrounding the kidneys and subsequent biopsies confirming the clinical suspicion of Erdheim-Chester disease. One patient was found to have colon cancer at the time of screening and subsequent to colectomy the retroperitoneal soft-tissue density resolved. One patient presented with a perirenal mass and lack of periaortitis and subsequently was discovered to have lymphoma. One patient was discovered to have a large pelvic tumor and was undergoing further histologic classification. A seventh patient had mild periureteral scarring secondary to a prior surgical manipulation and lacked radiographic evidence of periaortitis. Two other patients were excluded because of aneurysmal dilation of the infrarenal aorta.

The mean age of the 48 patients with RPF was 54.25 years (range, 23-74 yr); 26 were male and 22, female (Table 1). Twenty-nine of the patients were white, 7 were African American, 6 were African, 1 Hispanic, and 5 were other race/ethnicity. Thirty-seven patients were residents of the United States. Two patients were residents of Nigeria, 2 from Ethiopia, and 1 each from Turkey, East India, West Africa, Grenada, Bangladesh, Kenya, and Israel.

T1-2
TABLE 1:
Demographics, Comorbid Conditions, and Presenting Laboratory Values of 48 Patients With RPF

Forty-one patients had no history of attempted ureterolysis, whereas 7 patients had prior attempts at ureterolysis and were being referred for recurrent disease or systemic symptomatology. Of the 7 who had ureterolysis, 2 were bilateral and 5 were unilateral.

Table 2 lists reported "risk factors" for RPF and the number of patients in this cohort with those risk factors. Three patients had received therapeutic external beam radiation. The location, indication, and interval between radiation and onset of RPF in these 3 patients included tonsils (recurrent tonsillitis, 47 yr); shoulder (growth on skin, 52 yr); and spine (spinal cord glioma, 17 yr). Four patients had a history of β-blocker use. Three patients had taken atenolol for 7, 7, and 16 years, respectively, and 1 patient had taken metoprolol for 15 years. Eight patients had a total of 25 abdominal/pelvic surgeries: abdominal hysterectomy (n = 8), cholecystectomy (n = 5), bladder surgery (n = 3), appendectomy (n = 3), cesarean section (n = 3), lysis of adhesions (n = 1), gastric ulcer over-sewing (n = 1), and tubal surgery to restore fertility (n = 1).

T2-2
TABLE 2:
Patients With Traditional Risk Factors for RPF

Authors of several studies have suggested that occupational or environmental exposure to asbestos may be a risk factor for RPF.5,25,26 Uibu et al26 retrospectively performed occupational histories on 43 patients with RPF. They compared the risk of RPF to age- and sex-matched controls based on estimated exposure to asbestos. The authors reported a strong association with an odds ratio (OR) of 5.54 for patients with <10 fiber-years of asbestos exposure and an OR of 8.84 for those with 10 or more fiber-years of exposure. Unfortunately the authors did not differentiate between the various forms of periaortitis, as another risk factor for RPF in their series was the presence of an abdominal aortic aneurysm with an OR of 6.73. Six patients in our study (12.5%) had current occupations considered high-risk occupations for exposure to asbestos: printing pressman (n = 2), construction worker (n = 1), shipyard worker (n = 1), mason (n = 1), and salvage yard proprietor (n = 1). Chest X-rays were available on these patients, and none of them had evidence of pleural plaques. We did not, however, perform a detailed occupational history on our patients, nor did we prospectively perform high-resolution CT scans of the thorax. We cannot, therefore, eliminate asbestos exposure as a possible risk factor in the patients reported in our series.

Table 3 lists the clinical symptoms on presentation for patients with RPF. The most common presenting symptom was pain, which occurred in 45 of the 48 patients. The pain was generally located in 1 or both flanks with radiation to the inguinal area. Of the 3 patients who did not present with pain, 1 was discovered during CT scan for evaluation of weight loss and 2 were discovered by magnetic resonance angiography while undergoing evaluation for possible renal vascular hypertension.

T3-2
TABLE 3:
Presenting Signs and Symptoms of 48 Patients With RPF

One patient had a family history of rheumatic disease. Six patients had a known history of coronary artery disease. Sixteen were known to have hypertension before the onset of the RPF. No patient had a history of peripheral vascular disease. Four patients had known cerebral vascular disease, 9 patients were known to have diabetes, and 9 patients had the diagnosis of hyperlipidemia. Four patients were current smokers, 4 patients admitted the use of illicit substances, and 8 patients claimed current consumption of alcohol.

Thirty-two patients had ureteral obstruction requiring ureteral stenting. Twenty-two were bilateral, 4 were unilateral left-sided, and 6 were unilateral right-sided obstructions. Thirteen patients had received prior episodes of chemotherapy as treatment for RPF, either as monotherapy or combination therapy, for an average of 14 months (range, 2-30 mo) before referral for treatment failure. These treatment regimens included prednisone alone (n = 3), prednisone + methotrexate (n = 3), prednisone + azathioprine (n = 2), methotrexate alone (n = 1), tamoxifen and prednisone (n = 1), prednisone + methotrexate + tamoxifen (n = 2), and prednisone + cyclosporine (n = 1). Thirty-eight of the 48 patients had histologic confirmation of RPF by biopsy performed either before referral or to confirm the diagnosis. These biopsies were obtained either at the time of ureterolysis, via laparoscopic surgery, or via image-guided needle biopsy.

The average hemoglobin on presentation was 11.6 gm/dL (range, 7.7-15.2 gm/dL). Eighteen of the 48 patients presented with a hemoglobin of ≤11.0 gm/dL. The mean erythrocyte sedimentation rate was 40.5 mm/h (range, 1-150 mm/h). Three patients were diagnosed as hypothyroid before the initial visit and were on thyroid-replacement therapy. One patient had a diagnosis of multinodular goiter before the visit, and 1 patient was detected to have hypothyroidism during the initial screening. Two patients were discovered to have hyperthyroidism during the initial screening period. Nine patients were ANA positive with ranges of 1:20 to 1:60. Those patients positive for ANA were negative for anti-dsDNA.

The average size of the right kidney was 10.6 cm (range, 8.4-18.5 cm; normal values right kidney, 11.6-12.3 cm). The average size of the left kidney was 11.09 (range, 7.5-13.9 cm; normal values left kidney, 11.8-12.6 cm). Table 4 shows the results of the radiographic classification of patients with RPF.

T4-2
TABLE 4:
Radiographic Classification at Initial Visit for 48 Patients With RPF

Two patients had significant renal artery stenosis requiring endovascular stenting secondary to extrinsic compression. One patient had a left iliac artery stenosis that required stenting, and 1 patient had a right iliac artery stenosis that required stenting. Five patients had positron emission tomography (PET) scans before their initial appointment, all of which revealed increased infrarenal periaortic uptake of 18-fluorodeoxyglucose.

DISCUSSION

To our knowledge this is the largest series of patients with RPF reported from a single center, using a standardized definition, describing the clinical, laboratory, and radiographic presentation of this disease. [Editor's note: See also the new study by van Bommel et al29a and the commentary by Vaglio26a in this same issue.] It is important to recognize that RPF is a form of periaortitis.28 Inflammation and/or fibrosis surrounding the aorta and/or iliac arteries is the sine qua non of this disease and is required for the diagnosis. Other forms of periaortitis exist; these can be rapidly eliminated from the differential diagnosis by initial contrast-enhanced cross-sectional imaging and determining the presence or absence of a dilated infrarenal aorta. Clinicians must question the diagnosis of RPF if this imaging fails to demonstrate periaortitis or periiliacitis. In patients where periaortitis is absent, clinicians must recognize that they are likely dealing with a multitude of conditions and diseases that can cause fibrosis in the retroperitoneum with similar compromise to the retroperitoneal structures, but that these diseases are likely distinct from RPF with different strategies for treatment.

The demographics of the population reported here are similar to those of other reported series, but also contain important differences. As in most series reported in the literature, the average age of our population was in the early 50s.2,10 Although we report a large age range (18-74 yr), 73% of our population was aged between 40 and 65 years at the time of presentation. Unlike other large series, we did not see an overwhelming male population. This difference may reflect referral patterns, as early reports were from the urologic literature,2,10 or this difference may reflect the fact that these early reports used a different definition of RPF and included all forms of periaortitis and also included other fibrosing disorders of the retroperitoneum. A 2007 report from Europe where the type of periaortitis was taken into consideration is consistent with our findings.33

Eleven of the 48 patients (23%) in this report were born in Africa, the Middle East, or India. An additional 6 (13%) were of African ancestry. We are unable to find any reports describing the racial distribution of patients with RPF, and therefore we do not know if our population is similar to others reported in the literature.

Because the etiology of RPF is not known, many have attempted to correlate this disease with inciting events such as radiation, drugs, surgery, infections, and exposure to asbestos, arbitrarily dividing these patients into idiopathic or secondary RPF, despite a paucity of data to establish a clear cause-and-effect relationship. In our series 3 patients had a history of external-beam radiation. Two of these patients had radiation that was delivered above the diaphragm and on average 50 years before the onset of RPF. While the dose, area of exposure, and shielding used are not known for these patients, contemporary literature would suggest that radiation-induced fibrosis would manifest at the anatomic location of radiation with acute changes 4-12 months after treatment and progress over time.32 This presentation is not consistent with 2 of the 3 patients reported in the current report, and therefore we have not attributed these patients' RPF to their prior radiation. Our third patient had radiation delivered over the anatomic site of fibrosis, and late events have been reported especially when the field of exposure includes the genitourinary system.7 Therefore, we cannot eliminate the possibility that this patient's RPF was secondary to prior radiation exposure.

The use of β-blockers is considered in most reviews to be a potential risk factor for RPF. As far as we know, 7 reports of β-blocker use and RPF can be found in the literature to date.1,6,9,12,18,19,23 These reports, for the most part, antedate cross-sectional imaging, and cases were diagnosed as RPF based on intravenous pyelography, ultrasound, and pathology that showed fibrosis and inflammation surrounding the ureter obtained at the time of ureterolysis. It is unclear if these cases represented periaortitis or other fibrosing disorders, but given the large number of patients taking β-blockers worldwide and the limited case reports describing this association, the relationship seems unlikely.

A history of prior abdominal pelvic surgery is also traditionally listed as a risk factor. In the current report only 8 patients (17%) had prior surgery. These surgeries were common surgeries performed in an adult population, and a cause-and-effect relationship is not clear.

Seven patients had undergone ureterolysis before referral. Historically, ureterolysis was considered the "gold standard" for treatment of this disease. Successful outcomes were based on relief of ureteric obstruction and subsequent improvements in renal function. Larger series quickly recognized progression of disease despite anatomic correction, and corticosteroids were introduced into the postoperative treatment strategy, resulting in a doubling of successful outcomes.2 Unfortunately, as in the patients referred to our program, the contralateral side eventually becomes affected in 25% of those patients with unilateral ureterolysis, or there is persistent pain and other signs of systemic involvement, such as anemia or ongoing weight loss.

Thirteen patients had received several different combinations of immunomodulating therapy for varying periods of time before referral. The heterogeneity of the medications prescribed to treat RPF highlights the lack of guidance on appropriate treatment strategies and the lack of randomized controlled trials for this disease.

The most common presenting symptom in the current series was clearly pain. Over 90% of patients reported an acute onset of pain that mimicked ureteral colic and led to imaging to rule out ureterolithiasis. Unlike ureteral colic, however, this pain occurs on a baseline of more systemic symptoms including fatigue and weight loss. Weight loss in this population can be substantial. In our series the average weight loss was 28 pounds, with 2 patients having a 60-pound weight loss in the year before presentation. In male patients hydroceles were common; they occurred in nearly one-third of the population and may be an early marker of disease. Obstruction of the retroperitoneal vessels has been cited as a common cause of hydroceles.8 Edema in these patients results from obstruction or compression of the vena cava or the ilial-femoral veins. In the current series these patients were categorized as having radiographic class II disease. Lower extremity edema occurred in 60% of patients with class II disease, and symptomatic pulmonary emboli occurred in 3 (18%) of these patients. Given this high occurrence, one might consider prophylactic anticoagulation in this group of patients.

Early reports suggested that periaortitis may result from the exposure of oxidized lipids in the aorta and that underlying vascular disease may be required for RPF to occur.14,16,17 The patients reported in the current series do not show a strong history of vascular disease or the presence of traditional risk factors for vascular disease. Fewer than one-half have a history of hypertension or diabetes; only 10 patients had known cerebral, coronary, or peripheral vascular disease; and only 4 patients had tobacco exposure. Since we eliminated all patients with perianeurysmal fibrosis or inflammatory aortic aneurysms from this study, we may have eliminated the population originally reported by Parums et al.16

RPF is clearly an inflammatory disorder, with biopsy specimens showing an inflammatory infiltrate composed of lymphocytes, macrophages, plasma cells, and eosinophils interspersed between collagen bundles and sclerosis.28 Therefore, it is not surprising to see these patients present with anemia and elevated sedimentation rate, which are common findings in other vasculitic disorders. Fortunately, in patients with RPF, these abnormalities usually normalize with treatment.21

RPF has been documented to occur in patients with active inflammatory diseases including Still disease, membranous glomerulonephritis, pauciimmune glomerulonephritis, and psoriasis. Additionally, these patients have been reported to have circulating ANA, antismooth muscle antibodies, antithyroglobulin antibodies, anti-RO antibodies, and antineutrophil cytoplasmic antibodies (ANCA).4,27 In our report only ANA and anti-dsDNA antibodies were prospectively drawn. Only 25% were ANA antibody positive, and none was anti-dsDNA antibody positive. This number is less than the 42%-positive rate reported by Vaglio et al,27 and may reflect the fact that their report included all forms of periaortitis. Seven patients in the current series were found to have autoimmune thyroiditis in varying stages of the disease. All patients had antithyroglobulin antibodies.

We have proposed in this case series a radiographic classification system based on anatomic location of the disease in an attempt to standardize the extent of disease for future interventional trials. While our initial purpose in proposing such a classification system was to document the time from treatment to response based on location of disease, we learned several lessons that are relevant for this paper. By definition all patients have class I disease. Patients without the class I criterion (soft-tissue density surrounding the infrarenal aorta and/or iliac vessels) should be eliminated from future series and case reports; we hope this will add clarity to a confusing data set. Patients with class II disease appear to have a significant increase of thromboembolic events, and if this is confirmed by other series, may warrant prophylactic anticoagulation. Patients with class III disease have an obstruction of 1 or both ureters. In our experience these patients responded more slowly to immunotherapy than patients with class I or II disease (unpublished data), and one can expect prolonged immune-modulating therapy. Class IV disease carries different risks to the kidney in the form of compression of the hilar vessels. Although this class was the least frequently encountered, 14% were found to have renal artery stenosis requiring endovascular stenting.

In conclusion, we present here the demographic, clinical, laboratory, and radiographic presentation of a homogeneous group of patients with RPF. We have attempted to solidify a proper scheme of classification of the disorder, and we suggest an anatomic classification system that can be used for future interventional trials.

REFERENCES

1. Ahmad S. Association of metoprolol and retroperitoneal fibrosis. Am Heart J. 1996;131:202-203.
2. Baker LR, Mallinson WJ, Gregory MC, Menzies E, Cattell W, Whitfield H, Hendry W, Wickham J, Joekes A. Idiopathic retroperitoneal fibrosis. A retrospective analysis of 60 cases. Br J Urol. 1988;60:497-503.
3. Cooksey G, Powell P, Sigh M, Yeates W. Idiopathic retroperitoneal fibrosis. A long-term review after surgical treatment. Br J Urol. 1982;54:628-631.
4. Corradi D, Maestri R, Palmisano A, Bosio S, Greco P, Manenti L, Ferretti S, Cobelli R, Moroni G, Dei Tos A, Buzio C, Vaglio A. Idiopathic retroperitoneal fibrosis. Kidney Int. 2007;72:742-753.
5. Cottin V, Brillet P, Combarnous F, Duperron F, Nunes H, Cordien J. Syndrome of pleural and retrosternal "bridging" fibrosis and retroperitoneal fibrosis in patients with asbestos exposure. Thorax. 2008;63:177-179.
6. Doherty C, McGeown M, Donaldson R. Retroperitoneal fibrosis after treatment with atenolol. Br Med J. 1978;2:1786.
7. Dorr W, Hendry J. Consequential late effects in normal tissues. Radiother Oncol. 2001;61:223-231.
8. Duffy T. An anatomy lesson. N Engl J Med. 1994;331:318-320.
9. Johnson JN, McFarland JB. Retroperitoneal fibrosis after treatment with stenolol. Br Med J. 1980;280:864.
10. Lepor H, Walsh PC. Idiopathic retroperitoneal fibrosis. J Urol. 1979;122:1-6.
11. Marzano A, Rapani A, Leone N, Actis G, Rizzetto M. Treatment of idiopathic retroperitoneal fibrosis using cyclosporin. Ann Rheum Dis. 2001;60:427-428.
12. McClusky DR, Donaldson RA, McGeown MG. Oxprenolol and retroperitoneal fibrosis. Br Med J. 1980;281:1459-1460.
13. McDougal W, MacDonell R. Treatment of idiopathic retroperitoneal fibrosis by immunosuppression. J Urol. 1991;145:112-114.
14. Mitchinson M. Retroperitoneal fibrosis revisited. Arch Pathol Lab Med. 1986;110:784-786.
15. Moroni G, Gallelli B, Banfi G, Sandri S, Messa P, Ponticelli C. Long-term outcome of idiopathic retroperitoneal fibrosis treated with surgical and/or medical approaches. Nephrol Dial Transplant. 2006;21:2485-2490.
16. Parums DV, Brown DL, Mitchinson MJ. Serum antibodies to oxidized low density lipoprotein and ceroid in chronic periaortitis. Arch Pathol Lab Med. 1990;114:383-387.
17. Parums DV, Chadwick DR, Mitchinson MJ. The localisation of immunoglobulin in chronic periaortitis. Atherosclerosis. 1986;61:117-123.
18. Pierce JR Jr, Trostle DC, Warner JJ. Propranolol and retroperitoneal fibrosis. Ann Intern Med. 1981;95:244.
19. Rimmer E, Richens A, Gursten M, Rees R. Retroperitoneal fibrosis associated with timolol. Lancet. 1983;1:300.
20. Scavalli AS, Spadaro A, Riccieri V, Ricciuti G, Taccari E, Marini M, Zoppini A. Long-term follow up of low-dose methotrexate therapy in one case of idiopathic retroperitoneal fibrosis. Clin Rheumatol. 1995;14:481-484.
21. Scheel P, Piccini J, Rahman M, Lawler L, Jarrett T. Combined prednisone and mycophenolate mofetil treatment for retroperitoneal fibrosis. J Urol. 2007;178:140-144.
22. Smith RA, Cokkinides V, Brawley OW. Cancer screening in the United States, 2009: a review of current American Cancer Society guidelines and issues in cancer screening. CA Cancer J Clin. 2009;59:27-41.
23. Thompson J, Julian D. Retroperitoneal fibrosis associated with metoprolol. Br Med J. 1982;284:83-84.
24. Tiptaft R, Costello J, Paris A, Blandy J. The long-term follow up of idiopathic retroperitoneal fibrosis. Br J Urol. 1982;54:620-624.
25. Uibu T, Jarvenpaa R, Hakomaki J, Auvinen A, Honkanen E, Metsarinne K, Roto P, Saha H, Uitti J, Oska P. Asbestos-related pleural and lung fibrosis in patients with retroperitoneal fibrosis. Orphanet J Rare Dis. 2008;3:29.
26. Uibu T, Oska P, Auvinen A, Honkanen E, Metsarinne K, Saha H, Uitti J, Roto P. Asbestos exposure as a risk factor for retroperitoneal fibrosis. Lancet. 2004;363:1422-1426.
26a. Vaglio A. Retroperitoneal fibrosis: new insights into clinical presentation and diagnosis [Commentary]. Medicine (Baltimore). 2009;88:208-210.
27. Vaglio A, Palmisano A, Ferretti S, Alberici F, Casazza I, Salvarani C, Buzio C. Peripheral inflammatory arthritis in patients with chronic periaortitis: report of five cases and review of the literature. Rheumatology (Oxford). 2008;47:315-318.
28. Vaglio A, Salvarani C, Buzio C. Retroperitoneal fibrosis. Lancet. 2006;367:241-251.
29. Van Bommel E, Hendriksz T, Huiskes A, Zeegers A. Brief communication: tamoxifen therapy for nonmalignant retroperitoneal fibrosis. Ann Intern Med. 2006;144:101-106.
29a. Van Bommel EFH, Jansen I, Hendriksz TR, Aarnoudse ALHJ. Idiopathic retroperitoneal fibrosis: prospective evaluation of incidence and clinicoradiologic presentation. Medicine (Baltimore). 2009;88:193-201.
30. Van Bommel E, Siems C, Hak L, van der Veer S, Hendriksz T. Long-term renal and patient outcome in idiopathic retroperitoneal fibrosis treated with prednisone. Am J Kid Dis. 2007;49:615-625.
31. Warnatz K, Keskin AG, Uhl M, Scholz C, Katzenwadel A, Vaith P, Peter H, Walker U. Immunosuppressive treatment of chronic periaortitis: a retrospective study of 20 patients with chronic periaortitis and a review of the literature. Ann Rheum Dis. 2005;64:828-833.
32. Weiss E, Chung T. Clinical manifestations and treatment of radiation induced fibrosis. Up-To-Date. [serial online]. 2008; version 16.3. www.Uptodate.com; accessed January 18, 2009.
33. Wolyniec W, Kozuchowska M, Sworczak K, Jezior D, Rozanska-Kluziak A, Rudka R, Rojek-Trebicka J, Rutkowski B. When can we really diagnose retroperitoneal fibrosis? Nephrol Dial Transplant. 2007;22:1786-1787.

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