Year : 2006 | Volume
: 22 | Issue : 3 | Page : 277--278
Retro-peritoneal fibrosis: A rare presentation with localized unilateral perirenal fibrosis
Samiran Das Adhikary, Ganesh Gopalakrishnan
Dept. of Urology, Christian Medical College, Vellore - 632 004, Tamilnadu, India
Samiran Das Adhikary
Dept. of Urology, Unit II, Christian Medical College, Vellore - 632 004, Tamilnadu
We report a rare case of localized unilateral perirenal involvement in retroperitoneal fibrosis in a man presenting with left upper abdominal discomfort and generalized weakness. The increased diagnostic capabilities and imaging characteristics of computed tomography and magnetic resonance imaging are emphasized. Multiple tissue sampling for histopathological study should be done to rule out malignancy in cases of atypical site involvement.
|How to cite this article:|
Adhikary SD, Gopalakrishnan G. Retro-peritoneal fibrosis: A rare presentation with localized unilateral perirenal fibrosis.Indian J Urol 2006;22:277-278
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Adhikary SD, Gopalakrishnan G. Retro-peritoneal fibrosis: A rare presentation with localized unilateral perirenal fibrosis. Indian J Urol [serial online] 2006 [cited 2020 Oct 21 ];22:277-278
Available from: https://www.indianjurol.com/text.asp?2006/22/3/277/27644
Retroperitoneal fibrosis (RPF) is a rare disease characterized by the presence of chronic inflammation and marked fibrosis of retroperitoneal tissue, which commonly entraps the ureters, great vessels and other abdominal organs at lower lumbar region. Ureteral involvement is reported in 80-100% of cases at presentation. The idiopathic form of the disease accounts for more than two thirds of cases. The availability of imaging techniques, such as computed tomography (CT) and magnetic resonance imaging (MRI) has provided non-invasive methods of diagnosis and follow-up and the introduction of medical therapy has greatly improved patients' outcome.
A 70-year old non diabetic normotensive male presented with generalized weakness and left upper abdominal discomfort. He had no history of abdominal surgery. His general examination was unremarkable. Erythrocyte sedimentation rate (ESR) (60 mm) and C-reactive protein (CRP) (16 mg/L, normal <6 mg/L) were elevated but all the other laboratory findings were normal. Computed tomography showed a soft tissue lesion above the renal hilum involving aorta, venacava and superior mesenteric artery, extending to left perirenal area encasing the kidney without involving the ureters. After intravenous administration of contrast, the lesion showed poor enhancement and was better delineated from the kidney [Figure 1]. Subsequently the patient was also subjected to MRI examination for further evaluation of the perirenal tissue characteristics. T1- weighted images showed a retroperitoneal mass surrounding the left kidney and invading the renal hilum. The signal intensity of the mass was similar to that of the muscle and lower than the kidney and was slightly increased after the intravenous administration of gadolinium [Figure 2]. On T2-weighted images the mass appeared to be of lower signal intensity than the kidney. Isotope renogram did not reveal any obstruction to the left kidney but the function of left kidney was 35% [Figure 3]. Percutaneous CT-guided needle biopsy was done twice to rule out malignancy with a gap of three weeks time, which confirmed benign nature of the tissue showing only fibrosis and non specific inflammation. He was advised to take tamoxifen 20 mg once daily and kept on regular surveillance.
The clinical presentation of retroperitoneal fibrosis are nonspecific. Localized symptoms include back or abdominal pain, which is also the commonest clinical manifestation. The localized symptoms are usually preceded by or coexist with systemic or constitutional symptoms, which includes fatigue, low-grade fever, nausea, anorexia, weight loss and myalgias.
The results of routine laboratory tests are consistent with inflammatory disease: concentrations of acute-phase reactants, such as ESR and CRP, are high in 80-100% of patients. These laboratory tests are often used to monitor the clinical course of the disease, though they do not always reliably mirror disease activity.
On CT scan, idiopathic retroperitoneal fibrosis usually appears as a homogeneous plaque, isodense with muscle, surrounding the lower abdominal aorta and the iliac arteries and often enveloping the ureters and the inferior vena cava. Unlike the idiopathic form, most retroperitoneal fibrosis secondary to malignant diseases tend to displace the aorta anteriorly and the ureters laterally.
MRI allows the avoidance of nephrotoxic contrast medium and provides a better definition against the surrounding tissues, mainly when fat-saturation images are used. Idiopathic retroperitoneal fibrosis is hypointense in T1-weighted images; in T2-weighted images its intensity is high in the early or active stages of disease because of tissue edema and hypercellularity and low in the late stages. In typical cases a well-marginated soft tissue mass with obscuration of the aorta and inferior vena cava is seen. Although CT and MRI are the most reliable imaging modalities for the diagnosis and follow up of idiopathic retroperitoneal fibrosis, there are no standardized diagnostic criteria., In rare cases RPF presents as a single or multiple soft tissue irregular masses and the differential diagnosis from primary retroperitoneal tumor or malignant lymphadenopathy is very difficult.
Asymmetric or unusually localized masses, as in our case, are diagnostic dilemmas. Histological examination of the retroperitoneal tissue is needed when the mass shows atypical localizations. Atypical sites of RPF involvement include the small bowel mesentery, duodenum, colon, bladder, peripancreatic and epidural space. Cranial extension around the kidneys is very infrequent and has occasionally been reported.,,, 
The conditions that should be ruled out in cases of perirenal involvement are non-Hodgkin's lymphoma, histiocytosis, amyloidosis and extramedullary hematopoiesis. T2-weighted images in these entities usually reveal moderate to high signal intensity masses. But as mentioned previously, this finding is not specific. Rapidly growing benign plaque or early stage of RPF may also exhibit heterogeneity with high signal intensities due to the increased water content caused by acute inflammation; therefore, multiple tissue sampling is necessary as very few malignant cells may be mixed with inflammatory ones.
In our case of localized perirenal involvement, MRI strongly suggested RPF due to the presence of a mature fibrotic tissue. This was confirmed by the histological examination. In this report we describe the use of CT and MRI in establishing the diagnosis of RPF and role of multiple tissue sampling for histopathological examination to rule out malignancy. To our knowledge there have been only few publications worldwide concerning cases of RPF with unilateral perirenal extension without involving the ureters., Despite the development of new imaging techniques, tissue biopsy is required to establish the diagnosis of this very rare entity. The perirenal type of RPF distribution remains a diagnostic challenge to the urologist.
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