To study clinical presentation, laboratory results, imaging findings and treatment options and outcomes of retroperitoneal fibrosis (RPF). To determine whether it follows the same natural course and response to treatment in the Asian population as in the Western world.Medical records of patients diagnosed with RPF on imaging and histopathology between February 2010 and April 2016 were reviewed.Of the 21 patients analyzed, mean age at presentation was 50.81 years. The male to female ratio was 0.9:1. Pain was most common presenting complaint (95.23% cases), almost 85% cases were idiopathic and rests were postradiation induced. The median creatinine level was 1.8 mg/dL. The mean erythrocyte sedimentation rate (ESR) was 53.2 mm/h. Hydronephrosis was present in all patients and 47.6% had atrophic kidneys. Diffuse retroperitoneal mass was present in 61.1%. Ureterolysis with lateralization, omental wrapping or gonadal pedicle wrap was done in 17 cases. Two patients underwent uretero-ureterostomy. One patient underwent ileal replacement of ureter, and one ileal conduit. Eighteen patients received concurrent medical treatment, 11 were given tamoxifen, 2 steroids (Prednisolone), and five were given both. Of the 20 patients with follow-up, 70% had complete symptomatic relief; ESR improvement was seen in 77.8%. Follow-up ultrasound showed resolved and decreased hydronephrosis in 20% and 55% respectively. One patient had treatment failure and 17.65% had disease recurrence.RPF is a rare disease with varied presentation and outcomes. The male to female ratio may be equal in Asians and smoking could be lesser contributing factor. More Asian cohort studies are required to support same.

Retroperitoneal fibrosis (RPF) is a rare disease characterised by fibrous tissue proliferation in the retroperitoneum, with encasement of the ureters and large vessels of the abdomen as the most destructive of potentially severe complications. It can either be idiopathic, or secondary to infections, malignancies, or the use of certain drugs. The idiopathic form accounts for approximately 75% of the cases, and is usually responsive to immunosuppressive therapy. In recent years, the emergence of a new clinical entity, IgG4-related disease (IgG4-RD), shed light on many fibro-inflammatory disorders once thought to be separate clinical entities, although frequently associated in the so-called multifocal fibrosclerosis. Among these, together with sclerosing pancreatitis and cholangitis, pseudotumour of the orbit, idiopathic mediastinal fibrosis and other conditions, is idiopathic retroperitoneal fibrosis (IRF). Both IRF and IgG4-RD can be associated with a wide variety of disorders, usually governed by immune-mediated (and particularly auto-immune) mechanisms. In our review, we discuss the clinical and therapeutic challenges IRF presents to the internist, as well as the meaning of its recent inclusion in the IgG4-RD spectrum from a clinical practice standpoint.

Retroperitoneal fibrosis (RPF) is a rare disease characterized by fibroinflammatory tissue in the periaortic or periiliac retroperitoneum, where it frequently encases ureters. There is emerging evidence that a subset of this disease is part of a spectrum of multisystemic autoimmune diseases collectively referred to as "immunoglobulin G4 (IgG4)-related disease".We retrospectively analyzed 27 idiopathic RPF patients and identified a subset as IgG4-related RPF, which we categorized according to recently published comprehensive diagnostic criteria. We compared clinical and laboratory characteristics and response to treatment between the two groups.Of 27 total patients, 16 (59.3%) were diagnosed as having IgG4-related RPF, and these were predominantly male. They were also significantly older and more likely to have other organ involvement, hydronephrosis, and postrenal acute kidney injury (AKI) compared to those with idiopathic RPF. However, there was no difference in response rate to systemic steroid treatment.IgG4-related RPF accounts for a substantial portion of RPF cases previously identified as "idiopathic RPF" in Korea. Clinical and laboratory characteristics of IgG4-related RPF are similar to those of idiopathic RPF except for a striking male predominance, older age, and higher incidence of postrenal AKI in IgG4-related RPF. More comprehensive, prospective studies are needed to clearly distinguish IgG4-related RPF from idiopathic RPF based on clinical manifestation and to further assess treatment response and long-term prognosis.

Retroperitoneal fibrosis is characterized by fibrotic lesions around the abdominal aorta and common ileac artery causing ureteral obstruction. Secondary retroperitoneal fibrosis is associated with malignant disease, drugs, exposure to radiation and surgery. In contrast, the majority of retroperitoneal fibrosis is classified into idiopathic retroperitoneal fibrosis, for which immunological etiology has been suggested. Recently, idiopathic retroperitoneal fibrosis has been considered to be a spectrum of immunoglobulin G4-related disease, a systemic inflammatory disease, the concept of which has been developed during the past decade. In the management of retroperitoneal fibrosis, assessment of systemic lesions associated with immunoglobulin G4-related disease and the exclusion of secondary retroperitoneal fibrosis is mandatory. Histological examination of retroperitoneal lesions is desired for accurate diagnosis and management. Laparoscopic or open biopsy is often beneficial, although it is more invasive than needle biopsy. Treatment for idiopathic retroperitoneal fibrosis consists of meticulous glucocorticoid therapy based on that for immunoglobulin G4-related disease, which is expected to be highly effective. Ureteral obstruction is usually managed with conservative procedures, such as ureteral stenting or percutaneous nephrostomy. The goal of treatment for retroperitoneal fibrosis should be freedom from the stent/nephrostomy with withdrawal of the glucocorticoid in addition to salvage of renal function; however, conservative management does not always provide favorable outcomes. In contrast, aggressive surgical treatment, such as ureterolysis, can achieve the goal; however, the procedure is associated with high morbidity. Establishment of a consensus about treatment for idiopathic retroperitoneal fibrosis, including the optimal indications for the invasive surgical procedure and conservative management, is desired.© 2020 The Japanese Urological Association.

Retroperitoneal fibrosis (RF) is a rare disease of unclear etiology characterized by the presence of fibroinflammatory tissue in the retroperitoneal space, which can entrap and obstruct retroperitoneal structures, notably the ureters. The disease responds well to steroid therapy, but tends to recur even after years. The aim of our study was to evaluate the long-term renal outcome of patients affected by idiopathic retroperitoneal fibrosis looking for predictive risk factors for recurrence of the disease and progression to end-stage renal disease.Retrospective observational study of patients with idiopathic RF diagnosed from 2004 to 2017 and follow-up of at least 1 year after the end of first course therapy with steroid, with or without tamoxifen (TMX) and with urological procedures when applicable.Forty-three patients were included in the study. The follow-up was 93 ± 52 months. All the patients obtained remission after therapy that was maintained until the last observation in 26 of them. In 17 patients, there was at least one recurrence. Risk factors associated with relapse were identified and resulted in smoking habit, onset with acute kidney injury (AKI), low back pain and antinuclear antibodies (ANA) positivity. Renal function remained fairly stable during the long-term follow-up. The renal end-point (doubling of serum creatinine or ESRD) occurred in 8% of the patients; however, eGFR in patients with relapse was similar to that of non-recurrent at the diagnoses, but it decreased over time more in the relapsing than in non-relapsing patients (p group = 0.20; p time = 0.001; p time × group interactions = 0.04). Based on these 4 predictor conditions, patients were divided into "low risk" (with 0-1 risk factor), and "high risk" (3-4 risk factors). The renal end-point occurred in 40% of high-risk patients, while none of the low-risk patients reached it (p = 0.02).Smoking habit, AKI at diagnosis, ANA positivity and lumbar pain were associated with relapse of RF after initial remission due to steroid and/or TMX therapy; the combination of these conditions was also predictive of worse renal function outcome. Identification of risk factors for relapse can be useful not only to modulate the choice, the dosage of first-line treatment and the duration of maintenance therapy but also for preventing a progressive loss of kidney function, as well.

Retroperitoneal fibrosis (RPF) is a rare disorder consisting of idiopathic and various secondary forms and characterized by chronic inflammatory infiltrates and marked fibrosis in the retroperitoneal space. In idiopathic RPF (IRPF), 35-60% of cases have been reported to be IgG4-related RPF, the retroperitoneal lesions of IgG4-related disease (IgG4-RD). IRPF can frequently lead to renal insufficiency mediated by urinary tract obstruction and hydronephrosis irrespective of being IgG4-related or not. Clinical pictures, laboratory and imaging findings, and location of the urinary tract obstruction are generally similar in IgG4-related and non-IgG4-related IRPF although multiple organ involvement and serum IgG4 elevation may be characteristic of the IgG4-related forms. Periaortic/periarterial lesions are the most frequent cause of renal insufficiency. Although the response to glucocorticoids is generally good, relapse does occur in a considerable proportion of patients, and may require an additional immunosuppressive agent and/or urological intervention in cases with multiple relapses or refractory obstructive uropathy. In general, the prognosis of patients with IRPF is good, but careful attention needs to be paid to chronic kidney disease as a major complication and rupture of the affected aorta/artery as a life-threatening one. Further studies are necessary to better understand the pathogenesis of the disease and to establish the optimal diagnostic and therapeutic strategies for it.© 2021 Mizushima and Kawano.

Idiopathic retroperitoneal fibrosis (RPF), reviewed herein, is a rare fibro-inflammatory disease that develops around the abdominal aorta and the iliac arteries, and spreads into the adjacent retroperitoneum, where it frequently causes ureteral obstruction and renal failure. The clinical phenotype of RPF is complex, because it can be associated with fibro-inflammatory disorders involving other organs, is considered part of the spectrum of IgG4-related disease, and often arises in patients with other autoimmune conditions. Obstructive uropathy is the most common complication, although other types of renal involvement may occur, including stenosis of the renal arteries and veins, renal atrophy, and different types of associated GN. Environmental and genetic factors contribute to disease susceptibility, whereas the immunopathogenesis of RPF is mediated by different immune cell types that eventually promote fibroblast activation. The diagnosis is made on the basis of computed tomography or magnetic resonance imaging, and positron emission tomography is a useful tool in disease staging and follow-up. Treatment of idiopathic RPF aims at relieving ureteral obstruction and inducing disease regression, and includes the use of glucocorticoids, combined or not with other traditional immunosuppressants. However, biologic therapies such as the B cell-depleting agent rituximab are emerging as potentially efficacious agents in difficult-to-treat cases. Copyright © 2016 by the American Society of Nephrology.

We aim to review the most relevant diagnostic features and treatment options of retroperitoneal fibrosis, in order to provide a useful guide for clinical practice.The recent literature highlights the role of imaging studies such as computed tomography, magnetic resonance imaging and positron emission tomography as useful tools for the diagnosis of retroperitoneal fibrosis, with retroperitoneal biopsy being reserved to atypical cases. The treatment approach is mainly conservative and is based on the use of medical therapies plus urological interventions. Medical therapies essentially comprise glucocorticoids and immunosuppressants-either traditional or biological agents such as rituximab. Surgical ureterolysis is only left for refractory cases. Recent findings in retroperitoneal fibrosis highlight the possibility of a non-invasive diagnostic approach and a conservative treatment strategy.

Urinary kidney injury molecule-1 (KIM-1), neutrophil gelatinase-associated lipocalin (NGAL), and serum cystatin C (Cys C) are biomarkers of acute kidney injury (AKI). However, the efficacy of combining these indices to diagnose decompensated cirrhosis is unknown. This study involved 150 patients divided into AKI and non-AKI, and healthy individuals. Urinary KIM-1 and NGAL, serum Cys and creatine, and glomerular filtration rate (GFR) were compared based on Child-Pugh liver function class. Urinary KIM-1 and NGAL concentrations and serum Cys C levels were significantly higher in patients with AKI secondary to decompensated cirrhosis than in those with AKI not secondary to decompensated cirrhosis (p < 0.01). These were significantly associated with higher kidney injury index stages (p < 0.01) and negatively correlated with GFR in secondary AKI patients. Urinary KIM-1 and NGAL and serum Cys C increased significantly and GFR decreased as Child-Pugh class of decompensated cirrhosis significantly increased (p < 0.05). SCr levels were significantly increased in Child-Pugh class C patients (p < 0.05). Urinary KIM-1, urinary NGAL, serum Cys C, and the combined detection factor, as screening indices, could aid in the early diagnosis of AKI secondary to decompensated cirrhosis.