Saudi Journal of Kidney Diseases and Transplantation

: 2020  |  Volume : 31  |  Issue : 1  |  Page : 169--175

Retroperitoneal fibrosis in the military hospital of Morocco

Mounia Azizi, Yassir Zajjari, Hicham Rafik, Driss El Kabbaj 
 Department of Nephrology-Dialysis, Military Hospital Mohammed V, Rabat, Morocco

Correspondence Address:
Mounia Azizi
Department of Nephrology-Dialysis, Military Hospital Mohammed V, Hay Ryad BP 10100, Rabat


Retroperitoneal fibrosis (RPF) is a rare disease. It is characterized by the presence of fibro-inflammatory tissue involving retroperitoneal structures. The usual mode of presentation of this disease is with lumbar pain, kidney failure, and a biological inflammatory syndrome. The aim of our study is to describe the diagnostic, etiologic, therapeutic aspects and outcomes of RPF in a nephrology unit in Morocco. Twelve cases of RPF were included in our study. The mean age was 57 ± 10 years (32.70). Nine patients were male and three were female. Symptoms were highly variable, dominated by pain that was present in all patients. Venous compressive signs were described in four patients (33.3%), anuria in one patient (8.3%), and hematuria in two patients (16.6%). Laboratory examinations found an inflammatory syndrome in all patients and renal failure in nine patients (75%), with a mean serum creatinine at 35 mg/L ± 8.5. Diagnosis was suspected on the ultrasound data and confirmed by computed tomography or magnetic resonance imaging. RPF was idiopathic in nine patients (75%). It was secondary to aortic aneurysm in one patient (8.3%), Riedel’s thyroiditis in one patient (8.3%), and drug induced in another patient (8.3%). All patients received surgical treatment along with corticosteroids. At six months, remission was achieved in nine patients, whereas three others had steroid resistance. These patients were treated by mycophenolate mofetil (MMF) at a dose of 2 g/day; two of them had intestinal intolerance to MMF and thus were treated by tamoxifen at a dose of 40 mg/day. At 24 months, they stabilized their renal function with incomplete regression of the fibrotic plate. No cases of recurrence were observed during the study period.

How to cite this article:
Azizi M, Zajjari Y, Rafik H, El Kabbaj D. Retroperitoneal fibrosis in the military hospital of Morocco.Saudi J Kidney Dis Transpl 2020;31:169-175

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Azizi M, Zajjari Y, Rafik H, El Kabbaj D. Retroperitoneal fibrosis in the military hospital of Morocco. Saudi J Kidney Dis Transpl [serial online] 2020 [cited 2022 Jan 27 ];31:169-175
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Full Text


Retroperitoneal fibrosis (RPF) is a rare disease characterized by the presence of fibro-inflammatory tissue involving retroperitoneal structures. It frequently sheathes the ureters and the inferior vena cava.[1] RPF was first described by the French urologist Albarran in 1905 and became fully described as an entity in 1948 by Ormond.[2],[3],[4] This disease is often idiopathic or secondary to infections, abdominal surgery, taking drugs, or malignancies. Recently, idiopathic RPF is reported among the manifestations of IgG4 disease.[5] Because of its clinical polymorphism, the diagnosis of RPF is essentially based on imaging such as computed tomography (CT) or magnetic resonance imaging (MRI) along with laboratory findings and eventually histopathological examinations. The purpose of these investigations is to look for secondary RPF that requires specific etiological treatment. In general, the treatment of idiopathic RPF is often based on renal drainage, associated with corticosteroids and/or immunosuppression in some cases.

The aim of our study is to describe the diagnostic, etiologic, therapeutic aspects and outcomes of RPF in a nephrology unit in Morocco.

 Patients and Methods

This is a retrospective study conducted in the Nephrology Department of Mohammed V Military Hospital, Rabat, on patients admitted between January 2007 and December 2017. All patients in the department with RPF during this period were included in our study.

The diagnosis of RPF was based on typical imaging findings according to the Scheel CT classification [Table 1].[6]{Table 1}

We analyzed the clinical parameters including age, gender, smoking history, comor- bidities, general signs, functional and physical signs, laboratory findings including blood count (BC), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), serum crea- tinine level (SCL), cytobacteriological urine examination, immunological parameters such as antinuclear antibody (ANA), and other autoantibodies and therapeutic modalities.

The follow-up was based on clinical symptoms, biological parameters such as CRP and renal function, and radiological criteria. Remission was defined as a clinical improvement, a better renal function on follow-up compared to baseline, decrease of inflamma- tory syndrome, and improvement or stable findings in serial imaging. Steroid resistance was defined as a worsening of renal function, a worsening of inflammatory syndrome, and progression of fibrotic plate. Numerical data were expressed as the mean and standard deviation, and the categorical data were expressed as percentage and numerical values. Ethical approval for this study was provided by the Institutional Ethical Committee of our hospital.


General data

Twelve cases of RPF were included in our study. The mean age of the patients was 57 ± 10 years (32.70). Nine patients were male and three patients were female. Four patients were smokers, one patient had a history of tuberculosis, one patient had a history of ergo- tamine use, one patient had a history of Riedel’s thyroiditis, and one a history of malignant tumor. Comorbidities included hypertension in five patients and diabetes in two patients.

[Table 2] describes the clinical, biological, radiological characteristics and etiologies of our patients.{Table 2}

Clinical manifestations

Pain was present in all patients in the form of chronic low back pain in four patients, renal colic in four patients, and abdominal pain in four patients. General symptoms including weight loss, fever, and vomiting were seen, respectively, in eight, four, and three patients. Venous compressive signs have been observed in three patients (lower extremity edema) and one patient (varicocele). Anuria was described in one patient and hematuria in two patients.

Laboratory examinations

Elevated inflammatory markers were found in all patients; the mean CRP was 32 ±19 mg/L. The mean ESR was 54 ±7 mm/h and mean hemoglobin was 10 ± 1 g/dL. Renal failure was noted in nine patients (75%), with a mean serum creatinine at 35 ± 8.5 mg/L. Urine culture showed a urinary infection with Escherichia coli in three patients. ANA was positive in four patients and hypothyroidism with positive antithyroperoxidase antibodies in one patient. Rheumatoid factor was performed in only five patients and returned positive in two patients. Antismooth antibodies and ANCA were not done.

Radiological features

Abdominal ultrasound was performed in all patients and showed hydroureteronephrosis in all cases, bilateral in eight patients, and unilateral in four patients. All patients underwent abdominal CT which showed the fibrosis plate and its characteristics, as well as other associated lesions (aneurysm of the abdominal aortic aorta in one patient) and allowed monitoring after treatment. Fibrosis lesions were classified according to the Scheel’ s classification; Class III was found in all patients.

Histopathological findings

Biopsy of the retroperitoneal mass was performed in two patients. In one patient, that had a history of cervical cancer, the biopsy was performed by CT guided punctures in order to eliminate a malignant RPF (Case 1). In another patient that had a history of lung tuberculosis and micromediastinal lympha- denopathy on CT, the biopsy was done surgically so as to eliminate the tuberculous origin of RPF (Case 6). In both the patients, histo- logical examination of the fibrotic plate showed a nonspecific inflammatory infiltrate suggestive of a primary origin of RPF.


RPF was idiopathic in nine patients (75%) and secondary in three patients (25%). Aortic aneurysm, long-term medication by ergotamine, and Riedel’s thyroiditis were found in our series. However, in two cases, despite histo- pathological examination of fibrotic plate, we did not find any secondary etiology for RPF.

Treatments and outcome

The treatment was both medical and surgical. Eleven patients were treated with ureteral stenting. In only one patient, unilateral percutaneous nephrostomy by ultrasound-guided punctures was performed after ureteral stenting failure. Medical treatment included glucocorti- coids at a dose between 0.5 and 1 mg/kg/day in all patients. The mean duration of follow-up was 50 months ± 30 (6, 120). At six months, remission was achieved in nine patients, whereas three others had steroid resistance (case 2, case 4, and case 10; [Table 2]. These patients were treated by mycophenolate mofetil (MMF) at a dose of 2 g/day; two of them had intestinal intolerance to MMF and thus were treated by tamoxifen at a dose of 40 mg/day. At 24 months, they stabilized their renal function with incomplete regression of the fibrotic plate. No cases of recurrence were observed during the study period.


RPF is a rare inflammatory disease that can lead to compression of vascular and urinary structures, causing hydronephrosis. In a Finnish retrospective case-control study, the incidence was estimated at 1/106 inhabitants and the prevalence at 1.4/105 inhabitants.[7] In Morocco, to the best of our knowledge, only one study was reported by El Majdoub et al between 2005 and 2013. Thus, in this series, 12 patients were described and RPF was idiopathic in 75%.[8] In our series also, between 2007 and 2017, 12 patients were included. RPF occurs predominantly in the 4th, 5th, and 6th decades of life and most often affects men.[9],[10] Our study results showed that RPF occurred between the age of 32 and 70 years, which is similar to literature. Symptoms of RPF are nonspecific including pain, weight loss, signs of venous compression, and high blood pressure.[8],[11],[12],[13],[14],[15],[16],[17] In our study, pain was the chief complaint (abdominal, back, or renal colic), present in all patients. In contrast, signs of locoregional compression such as oligoanuria was predominant in Lugosi et al’s series.[16]

[Table 3] shows the different clinical features reported in the literature compared to our results.{Table 3}

In general, laboratory examination of RPF reveals an inflammatory syndrome with high CRP and ESR in 80%-100% of cases associated with renal failure.[11] These inflammatory markers have been used also as a reference for monitoring of the disease under treatment. Acute renal failure is found in 62%-92% of cases in multiple reports, and the mechanism is often obstructive.[13],[14] In our study, acute renal failure was found in 75% of the cases, with a mean serum creatinine level at 32.41 ± 18.93 mg/L. CRP was elevated in all patients which is similar to results reported by Kaaroud in his series.[17]

The pathogenesis of RPF is not well known, and autoimmunity markers are frequently found, including ANA (60%), rheumatoid factors, antismooth muscle antibodies, and antineutro- phil cytoplasmic antibodies.[1],[18] However, their incidence is poorly evaluated and their therapeutic implication is not well described. In this study, all patients received an autoimmunity antibody assay, which was reported positive (ANA) in four patients (33.3%).

Ultrasonography is the least invasive and simplest examination to evoke the diagnosis. In this study, abdominal ultrasound was performed in all patients and found hydro- uretero-hydronephrosis in all patients, eight were bilateral, and four were unilateral. Currently, CT and MRI are considered the mainstay of choice for the diagnosis of RPF. They allow the direct visualization of the fibrous plaque by specifying the exact topography and the relations with the adjacent structures. They also help in the etiological diagnosis.[20] In our study, the only type of radiological finding seen was type III (compression of one or both ureters) which is similar to previous studies.[17]

Two forms of the disorder have been described. Idiopathic RPF accounts for more than two-thirds of cases. Secondary RPF causes are dominated by drugs such as ergot derivatives, beta-blockers, and analgesics, and other causes include radiotherapy, malignancies, and inflammatory or infectious diseases.[1],[21] [Table 4] shows our findings compared to other series of RPF in the literature.{Table 4}

Histological diagnosis is considered not necessary for initiating medical treatment. Clinical context, imaging, and laboratory findings guide the biopsy indications. In this study, biopsy was carried out in two of our patients (16.6%), thus excluding a secondary origin of the RPF.

The aims of therapy are: relieving urinary obstruction, decreasing the inflammatory syndrome, limiting the progression of fibrosis, and preventing disease from relapse.[1] It consisted of a combination of medications and surgical intervention (ureteral stenting or nephrostomy), and medical treatment is based on corticosteroids that remained the treatment of choice in RPF. Many immunosuppressive strategies were described in previous studies for treating RPF in case of resistance or intolerance.[3],[25] In our study, corticosteroids were prescribed in all patients with a remission at 75% which is similar to several clinical series reported in literature.[10],[11],[12],[17],[24],[26] In RPF secondary to the aortic aneurysm, even after surgical treatment of the latter, regression of the fibrous plaque remains controversial. In this study, patients with RPF secondary to aorta aneurysm and whose diameter did not exceed 5 mm did not warrant endovascular treatment, and there was a regression of the plate under corticosteroid therapy itself.

The outcome of RPF is unpredictable even after treatment. It depends on several factors: age of patients, early diagnosis, extension of the fibrous process, and etiology. Although spontaneously regressive forms have been described, the most usual outcome is toward the aggravation of the disease.[21],[27] In our study, with a mean follow-up duration of 50 months, remission was achieved in nine patients, whereas three patients had steroid resistance.

 Limitations of the study

Limitations of this study are its retrospective design, small sample size due to the rarity of the disease, and lack of standardization of treatment. Therefore, further larger sample and prospective studies are required.


In Morocco, RPF is rare and often idiopathic. This information provides a contribution toward understanding the characteristics of RPF in Africa and Arab countries with implications for planning of future multicentric studies.

Conflict of interest: None declared.


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