Multiple Myeloma and Retroperitoneal Fibrosis: A Rare Association Report and Literature Review.

Multiple myeloma (MM) is a common hematological malignancy. Autologous hematopoietic stem cell transplantation (auto-HSCT) can significantly improve the prognosis of patients with MM, but a variety of complications may occur after transplantation. Retroperitoneal fibrosis (RPF) is a rare cause of obstructive nephropathy. Because there are no specific symptoms at the time of onset and the course of the disease is often insidious, special laboratory and instrumental examination methods are usually needed to confirm the diagnosis. This article describes the clinical case of a 50-year-old female patient diagnosed with multiple myeloma. She developed postoperative acute kidney injury (AKI) more than 20 days after transplantation and was subsequently diagnosed with retroperitoneal fibrosis. After multidisciplinary collaboration, early transurethral vesicoureteral stent placement was performed, the obstruction was relieved, and her renal function returned to normal. Reports of retroperitoneal fibrosis after multiple myeloma transplantation are relatively rare. This case report advances our understanding of these 2 diseases, and the correlation between MM and RPF warrants further exploration.

Interesting New Findings of Retroperitoneal Fibrosis: Three Cases.

OBJECTIVE: Retroperitoneal fibrosis is a rare disease characterized by chronic inflammation and fibrosis in the retroperitoneal space that may wrap around the ureter and cause an obstruction. Here we present the cases of three patients diagnosed and treated between April and August 2022. CASE PRESENTATION: Here we present three cases of retroperitoneal fibrosis. Imaging revealed hydronephrosis and/or ureteral dilation, whereas laboratory findings such as erythrocyte sedimentation rate, C-reactive protein, and immunoglobulin G4 were abnormal. Serum creatinine and blood urea nitrogen levels suggested renal injury. Additionally, two patients had unclear diagnoses from other hospitals. Later, all patients underwent ureteral stenting and laparoscopic ureterolysis at our hospital and simultaneous diagnosis by biopsy. The two patients with high immunoglobulin G4 levels exhibited extremely severe fibrosis. After discharge, each received maintenance prednisone to prevent recurrence as well as methotrexate, followed by follow-up every 3 months. Fortunately, serum creatinine, blood urea nitrogen, and intravenous urography findings remained normal with an average follow-up of 8.5 months. CONCLUSION: Here we discovered interesting findings in the diagnosis and treatment of retroperitoneal fibrosis, including the stable effect of medical plus surgical treatment, an unclear ureteral obstruction etiology, and the relationship between immunoglobulin G4 level and fibrosis hardness. However, the mechanisms behind these new findings require further study.

Left Ureterocalycostomy With Ileal Interposition for Retroperitoneal Fibrosis in Patient With Erdheim-Chester Disease.

BACKGROUND: Erdheim-Chester disease (ECD) is a rare progressive non-Langerhans' cell histiocytic multisystem disorder with a broad spectrum of clinical manifestations, including infiltrative perinephric with ureteral involvement resulting in hydronephrosis, renal atrophy, and eventual renal failure. OBJECTIVE: To present a patient with ECD with bilateral renal/ureteral involvement managed with bilateral percutaneous nephrostomy tubes (PCNT) and trametinib who underwent bilateral robotic upper tract reconstruction, the first such published report. The video demonstrates only the left-sided repair, which posed specific challenges and demonstrates reconstructive techniques useful in complex upper tract repairs with limited tissue availability. MATERIALS AND METHODS: A 35-year-old male initially presented with baseline creatinine of 1.62 and split renal function; 30% right and 70% left by Lasix renogram. Extra-genitourinary manifestations of disease included cardiac hypertrophy and skin ulcers/lesions. Bilateral retrograde pyeloureterography showed proximal ureteral obliteration ∼4 cm bilaterally. Multiple management options were discussed including PCNTs, but patient elected for definitive repair. He was seen by Cardiology and Anesthesia and deemed to be optimized. He held his trametinib for 1week before surgery. We demonstrate a difficult ureteral dissection with fibrotic hilum preventing separation. Simultaneous ureteroscopy identified the distal extent of stricture which was excised, leaving a ∼15 cm gap. Downward nephropexy was performed with ultrasound guidance to identify an inferior calyx. Partial nephrectomy was then performed without vascular control due to hilar fibrosis. Ileal interposition was chosen to bridge the remaining ∼8 cm gap. Proximal ileo-calyceal and distal ileo-ureteral anastomoses were performed. We then placed a 30 cm × 7 Fr double-J ureteral stent in standard fashion. The ileum was secured to the renal pelvis to maintain a straight lie and an omental flap was secured in place. RESULTS: Immediate postoperative course was complicated by partial small bowel obstruction leading to a negative exploratory laparotomy and a subsequent episode of urosepsis. The patient is now voiding well without stents or PCNTs, without infections and with improving renal function, now with GFR (glomerular filtration rate) of 62 from 43 preoperatively. With aggressive hydration, patient has had no obstruction of the distal ureter with mucus. MRI Abdomen/Pelvis 6months later showed irregularity of the calyces with stable mild hydronephrosis. The patient continues to be medically managed on trametinib for his underlying disease, with surveillance for recurrent fibrosis and obstruction which has not yet occurred. CONCLUSION: Robotic ureterolysis and ureterocalycostomy with possible bowel interposition is a reasonable option for upper tract reconstruction in select patients with ECD.

IgG4-related retroperitoneal fibrosis with acute kidney injury: a case report and literature review.

IgG4-related retroperitoneal fibrosis is a rare cause of renal dysfunction that usually manifests as obstructive nephropathy (sometimes with extrarenal manifestations). Due to the non-specific symptoms at the onset of the disease and often latent course, special laboratory and instrumental examination methods are usually needed to establish a diagnosis. The article describes a clinical case of a relapse of IgG4-related retroperitoneal fibrosis in a 53-year-old patient, who developed bilateral ureterohydronephrosis with postrenal acute kidney injury after the withdrawal of glucocorticoid therapy. The patient underwent bilateral percutaneous nephrostomy and resumed glucocorticoids at a dose of 30 mg/day. Postobstructive diuresis was 22 L. Treatment resulted in a complete normalization of the creatinine level and transient hypokalemia, which was eliminated with potassium medications. At the final stage of the treatment, bilateral stenting of both ureters was performed with a tapering of glucocorticoids to 5 mg per day with CT control of the retroperitoneal space after 5 months. A clinical case demonstrates that an interruption of glucocorticoid treatment in patients with IgG4-related retroperitoneal fibrosis can lead to ureterohydronephrosis with the development of acute kidney injury. In such cases, stenting of the ureters could be considered an optimal therapeutic option.

Successful therapy of retroperitoneal fibrosis due to IgG4-related disease with rituximab, cyclophosphamide and glucocorticoids followed by maintenance therapy wit ritutixmab.

Idiopathic retroperitoneal fibrosis (IRF) is a rare condition characterized by the development of a peri-aortic and peri-iliac tissue showing chronic inflammatory infiltrates and pronounced fibrosis. Ureteral entrapment with consequent obstructive uropathy is one of the most common complications, which can lead to acute renal failure and, in the long term, to varying degrees of chronic kidney disease. Common symptoms at onset include lower back, abdominal or flank pain, and constitutional symptoms such as malaise, fever, and anorexia and weight loss. Pain is frequently referred to the hip, to the groin and to the lateral regions of the leg, with nocturnal exacerbations, and typically does not modify with position. We report a case of 56 year-old male with recurrent lower back pain and lower abdominal pain. Contrast-enhanced computed tomography and was suggestive of retroperitoneal fibrosis and unilateral ureteral occlusion. Histologic examination with immunohistochemical staining for IgG4 demonstrate IgG4-related retroperitoneal fibrosis. Therapy was started with prednison 1 mg/kg, but the tolerance of this dose was poor. Therefore the therapy was switched to combination of rituximab 375 mg/ m2 on day 1, cyclophosphamide 300 mg/m2 mg infusion and dexamethasone 20 mg total dose infusion on day 1 and 15 in 28 days cycle. FDG-PET/CT control in fourth month showed residual accumulation of FDG in retroperitoneal fibrotic mass, and therefore the therapy was prolonged to 8 month. The subjective symptoms of this diseases disappeared in the 8th month. Then the maintenance therapy, administration of rituximab in 6 month interval, was started. The activity of this disease be further evaluated by FDG-PET/CT imagination. Glucocorticoids are considered the cornerstone of therapy. The use of other immunosuppressive agents, including cyclophosphamide, azathioprine, methotrexate, mycophenolate mofetil and biological agents such as rituximab, tocilizumab and infliximab and sirolimus have been reported as a valuable option mostly in case reports, cases series and small studies. This agents allowed to reduce cumulative dose of glucocorticoids and its adverse effects. Therefore in our patients we preferred combination of rituximab cyclophosphamide s dexamethasone with lover dose of prednisonem. This combination is preferable for patients who cannot tolerate glucocorticoids or who are likely to suffer from significant glucocorticoids -related toxicity.

A case of immunoglobulin G4-related retroperitoneal fibrosis and hypophysitis with antecedent respiratory disease followed by spontaneous remission and recurrence.

A 65-year-old man presented with apparent bronchopneumonia. After treatment with antibiotics, he showed eosinophilia. Computed tomography (CT) imaging revealed bilateral consolidation, ground-glass opacities with nodular consolidations, and pleural effusion. Lung biopsy showed organising pneumonia with lymphoplasmacytic infiltration in the alveolar septa and in the thickened pleura and interlobular septa. All pulmonary abnormalities spontaneously went into remission within 12 months. At 73 years old, a follow-up CT scan revealed small nodules in both lungs and the review of the head CT scan showed thickening of the pituitary stalk in studying prolonged headache. Two years later, he visited the hospital complaining of severe oedema on the lower extremities with high serum immunoglobulin (Ig)G4 186 mg/dl. A whole-body CT scan showed retroperitoneal mass surrounding aortic bifurcation and compressing inferior vena cava, pituitary stalk thickening and gland swelling, and enlarged pulmonary nodules. Anterior pituitary stimulation tests showed central hypothyroidism, central hypogonadism, and adult growth hormone deficiency with partial primary hypoadrenocorticism. Retroperitoneal mass biopsy showed storiform fibrosis and obliterative phlebitis with marked lymphoplasmacytic infiltration with moderate IgG4-positivity. Immunostaining of the former lung specimen revealed dense interstitial infiltration of IgG4-positive cells. These findings indicated metachronous development of IgG4-related disease in lung, hypophysis, and retroperitoneum, according to the recent comprehensive diagnostic criteria of IgG4-related disease. Glucocorticoid therapy ameliorated oedema, on the other hand, unmasked partial diabetes insipidus at the initial dose of the treatment. Hypothyroidism and retroperitoneal mass regressed at 6 months of the treatment. This case warns us that long-term follow-up from prodromal to remission is necessary for the treatment of IgG4-related disease.

Chronic periaortitis: A clinical approach.

Chronic periaortitis (CP) is a rare disease characterised by the presence of a fibro-inflammatory tissue typically enveloping the abdominal aorta, the iliac arteries and, in some cases, the nearby structures, such as the ureters and the inferior vena cava. Imaging plays a key role in the diagnosis and follow-up: computed tomography and magnetic resonance imaging scans are used to define the extension of the pathological tissue, whereas fluorodeoxyglucose positron emission tomography is the gold standard to establish the degree of its metabolic activity. CP must be distinguished from secondary forms of periaortic infiltration, which include malignant, infectious, and drug-related aetiologies. This review focuses on the clinical aspects of CP and the differential diagnosis with secondary cases, and aims to provide the clinician with a guide through this challenging clinical approach.

Minimally invasive ureterolysis and intraperitonealization of ureter for idiopathic retroperitoneal fibrosis; single center analysis of an erratic disease.

INTRODUCTION: Idiopathic retroperitoneal fibrosis is a known cause of obstructive uropathy. Ureterolysis is done when medical management fails or the presentation is at an advanced stage. Conventionally ureterolysis without omental wrap has been considered incomplete. Our Institute has experience of laparoscopic or robotic ureterolysis with intraperitonealization of the ureter alone and no other adjunctive procedure. This study retrospectively assesses the result of the procedure with patients presenting with varying severity of disease. METHODS: From 2008, all patients who underwent laparoscopic or robotic ureterolysis were analyzed retrospectively for pre-operative management, operative findings, and post operative outcomes. RESULTS: We operated and released nine renal units in seven patients. Two of the nine cases were performed robotically completely and the rest was performed by laparoscopic approach. Median follow up was 60 months. All patients documented resolution of symptoms. The mean post-operative creatinine at 1 year was significantly decreased to 1.47 ± 0.49 mg/dl in comparison to preoperative creatinine (p < 0.05). The postoperative mean ESR decreased significantly from a preoperative value of 58.2 ± 19.41 mm to 15.8 ± 17.23. The nuclear scan revealed unobstructed drainage and radiological imaging revealed resolution of hydronephrosis and fibrosis in all. The mean GFR on the nuclear scan after 3 and 12 months of surgery was 36.3 ± 4.33 and 40 ± 3.77, respectively. Thus, there was significant increase noted in GFR at 3 and 12 months in comparison to preoperative GFR (p < 0.05). CONCLUSION: Laparoscopic/robotic ureterolysis with intraperitonealization alone is secure and durable procedure for idiopathic retroperitoneal fibrosis needing surgical release.

Effective therapy of pirfenidone in a patient with idiopathic retroperitoneal fibrosis: report of a case.

Idiopathic retroperitoneal fibrosis (iRPF) is a chronic autoimmune disease characterized by fibroinflammatory tissue surrounding the abdominal aorta and iliac arteries and extending into the retroperitoneum to envelop neighboring structures. Hydronephrosis due to obstruction of ureters is the most common complication of iRPF. Glucocorticoid with or without immunosuppressants or tamoxifen, the mainstay of iRPF treatment, usually brings good response. Nevertheless, in some conditions, the obstruction of ureters remains unresolved with the treatment of all these medications. One of the reasons lies in the innate feature of the fibroinflammatory tissue. The proliferation of fibrosis tissue in addition to inflammation in the mass was associated with insufficient response to immunosuppressive therapies. Pirfenidone, an anti-fibrosis agent, has been successful in treating pulmonary fibrosis and renal fibrosis. Therefore, it is rationale to assume the effectiveness of pirfenidone in the treatment of iRPF. In the current article, we report a 61-year-old Chinese man with iRPF who responded well to pirfenidone.

Idiopathic retroperitoneal fibrosis with endometrial cancer: a case report and literature review.

BACKGROUND: Retroperitoneal fibrosis is a rare disease characterized by chronic nonspecific inflammation, which leads to clinical compression manifestations of retroperitoneal organs especially ureter. Approximately 70 percent of retroperitoneal fibrosis cases are idiopathic which has no clear etiology. This study reported a rare case of a 48-year-old woman presented with idiopathic retroperitoneal fibrosis and endometrial cancer. CASE PRESENTATION: A 48-year-old woman presented with irregular vaginal bleeding without abdominal pain, bloating or discomfort. The patient was diagnosed iRPF after splenectomy 13 years ago. Then she took prednisone for 2 years and took tamoxifen for about 11 years. She stopped taking the medication from October 2019 to May 2020 and then started taking tamoxifen again until November 2020. Two weeks after she stopped taking tamoxifen, she presented with irregular vaginal bleeding. Gynecological ultrasound revealed a thick endometrium with uneven echo enhancement and blood flow signals. Then diagnostic curettage was performed with pathological examination showed endometroid carcinoma. Later, the patient was admitted to Peking University Third Hospital for surgery. Preoperative imaging examinations, including CT, MRI, and PET/CT, all showed pelvic enlarged lymph nodes and they were highly suspected to have lymph node metastasis. The patient underwent laparoscopic surgical staging and enlarged lymph nodes in the pelvic and aortic regions were removed. Finally, the pathology confirmed that endometrioid adenocarcinoma and fibrosis, but there was no tumor infiltration in these enlarged lymph nodes. The patient is now in good condition. CONCLUSION: This case report stressed the difficulty to distinguish between lymph node metastasis and inflammatory hyperplasia by common imaging methods. Due to increased surgical difficulty among retroperitoneal patients, lymphadenectomy should be carefully evaluated to avoid additional surgical complications and over-treatment.

IgG4-related disease diagnosed in a paratesticular pseudotumor simulating malignancy, in a patient with retroperitoneal fibrosis.

IgG4 related disease is a term used to describe a fibroinflammatory condition characterized by storiform fibrosis, inflammation with a dense lymphoplasmocytic infiltrate rich in plasma cells expressing IgG4, and often, if not always, raised serum levels of IgG4. We report a case of a patient with a past history of retroperitoneal fibrosis presenting with a swollen left testicle, who underwent an orchidectomy due to suspicion of malignancy. The surgical specimen revealed a paratesticular pseudotumor with histopathological and immunohistochemical characteristics of IgG4 related disease. To the best of our knowledge, just nine such cases have previously been reported, of which only three were manifestations of systemic disease, as in the present case. Whilst it is important to recognize the clinical and radiological features of this entity, histopathology is often essential in order to confirm the diagnosis.

Retroperitoneal fibrosis - diagnosis and treatment.

Idiopathic retroperitoneal fibrosis (IRF) is a rare condition characterized by the development of a peri-aortic and peri-iliac tissue showing chronic inflammatory infiltrates and pronounced fibrosis. Ureteral entrapment with consequent obstructive uropathy is one of the most common complications which can lead to acute renal failure and, in the long term, to varying degrees of chronic kidney disease. Common symptoms at onset include lower back, abdominal or flank pain. Pain is frequently referred to the hip, to the groin and to the lateral regions of the leg, often with nocturnal exacerbations and not responding to position changes. The disease is commonly associated with signs of systemic inflammatory response (malaise, fever, and anorexia and weight loss). Glucocorticoids are considered the cornerstone of the therapy. The use of other immunosuppressive agents, including cyclophosphamide, azathioprine, methotrexate, mycophenolate mofetil and biological agents such as rituximab, tocilizumab and infliximab have been reported as a valuable option mostly in case reports, cases series and small studies. These agents allowed to reduce cumulative dose of glucocorticoids and their adverse effects. Combined therapy is preferable for all patients who suffer from significant glucocorticoid- related toxicity or in cases where glucocorticoids alone are insufficient to treat the condition.

Comparison of Laparoscopic and Open Ureterolysis for Retroperitoneal Fibrosis: Results from a Tertiary Referral Center.

Objectives: To compare the surgical outcomes of open and laparoscopic ureterolysis procedures in patients requiring surgical treatment for ureteral obstruction caused by retroperitoneal fibrosis (RPF). Materials: This study was designed retrospectively. The clinical records of patients who underwent ureterolysis between January 2005 and April 2019 because of ureteral obstruction caused by RPF were examined. According to the type of surgery, the patients were divided into two groups as Group 1 (open ureterolysis) and Group 2 (laparoscopic ureterolysis). Demographic features, preoperative-postoperative renal functions, duration of follow-up with ureteral stents, and perioperative-postoperative complications were examined. The requirement of ureteral stent placement during the follow-up period was accepted as unsuccessful ureterolysis. Results: Ureterolysis was performed in 13 patients and 23 renal units. Eleven of these patients were men and two were women. The median age of the patients was 54 (44-68) years. There were six patients and 12 renal units in Group 1 and seven patients and 11 renal units in Group 2. Postoperatively, a total of four patients (30%) had minor complications (Clavien-Dindo 1-2) and one patient had a major complication (Clavien-Dindo 3a). Ureterolysis was determined to be effective in 21 of the renal units (91%) [11/12 (92%) in Group 1 vs 10/11 (91%) in Group 2]. No statistically significant difference was found between the groups in terms of the success and complication rates (p = 1 and p = 0.529, respectively). Postoperative hospitalization length and recovery time to return to normal preoperative activities were significantly shorter in Group 2 than in Group 1 (p = 0.011 and p = 0.041, respectively). Conclusions: The success and complication rates were similar between the open and laparoscopic methods for ureterolysis. Laparoscopic approach was advantageous over open approach in terms of postoperative hospitalization length and recovery time to return to normal preoperative activities.

[Chronic Periaortitis]. / Chronische Periaortitis.

Chronic Periaortitis Abstract. The term chronic periaortitis encompasses several fibroinflammatory diseases that manifest on or around the abdominal aorta which may be associated with aneurysm formation. Formerly distinct entities are grouped together, such as idiopathic retroperitoneal fibrosis (Ormond's disease), inflammatory aortic aneurysm, and perianeurysmal retroperitoneal fibrosis. They may also occur IgG4-related. The most common complications of these systemic inflammatory diseases are ureteric obstruction and secondary renal failure, but venous compression with congestion and thrombosis may also occur. This review focuses on the diagnosis and treatment of chronic periaortitis. The diagnosis is usually made by cross-sectional imaging, and various therapies, especially immunosuppressive agents, are used therapeutically, although good evidence is largely lacking. For bridging, a ureteric stent is often placed and in individual cases surgical therapy is also necessary. Due to the heterogeneity of the diseases and their rarity, there are hardly any standardized treatment procedures.

Unknown Extra-Articular Manifestation of Spondyloarthritis: What About Retroperitoneal Fibrosis? A Case Based Literature Review.

INTRODUCTION: Retroperitoneal fibrosis (RPF) is a rare disease characterized by fibroinflammatory tissue proliferation in the retroperitoneum. It results in a chronic inflammatory and fibrosis condition, possibly leading to compression of the retroperitoneal structures, especially to encasement of the ureters and the inferior vena cava. It may have an idiopathic or a secondary origin. Spondyloarthritis (SpA) is one of the rare conditions described among the secondary forms. CASE PRESENTATION: Herein, we report a new case of RPF in a patient with AS presented with acute abdominal pain radiating to the lumbar region and the left testicle. On clinical examination, we found a mild stiffness of the lumbar spine and a decrease in chest expansion. Sacroiliac joint pain was also found. The rest of the physical examination was normal. Laboratory tests showed inflammation with increased C-reactive protein (130 mg/l) and creatinine (112 micromol/l) levels. The computed tomography scan revealed a soft tissue density mass located around the sub-renal aorta. Diagnosis of idiopathic RPF associated with AS was retained. The patient was treated with a daily dosage of 1 mg/kg of oral glucocorticoid with a good outcome. CONCLUSION: RPF is a rare condition that can be either idiopathic or secondary. Its association with spondyloarthritis, mainly in its ankylosing spondylitis form, seems to be more than anectodal. Treatment may involve medical therapy and/or surgical management. KEY MESSAGE: In the presence of back pain, fatigue, weight loss, and low grade fever in spondyloarthritis patients, physicians should screen for retroperitoneal fibrosis as it could be a possible cause.

Utility of Ultrasonography in Assessing Periaortitis Associated with Retroperitoneal Fibrosis: A Case Report.

Periaortitis is a rare vascular manifestation and is often associated with retroperitoneal fibrosis. Herein, we describe a case of periaortitis accompanied by retroperitoneal fibrosis in a patient who developed acute kidney insufficiency due to bilateral ureteral stenosis. Ultrasonography at presentation detected thickness of the outer layer of the bilateral common iliac artery and right internal and external iliac arteries, consistent with periaortitis. Moreover, follow-up ultrasound images revealed subsiding of the thickness of the arterial wall in response to treatment with corticosteroids. Because of its noninvasiveness and handiness, ultrasonography has become popular for the assessment of large vessels in clinical practice, particularly monitoring for affected lesions. Computed tomography, magnetic resonance imaging, and positron emission tomography are currently used for the diagnosis and monitoring of periaortitis, but in this case, ultrasonography was utilized in the diagnosis and monitoring of periaortitis as a supportive imaging modality, as the use of contrast agents was contraindicated because of renal insufficiency.

Retroperitoneal Fibrosis Is Still an Underdiagnosed Entity with Poor Prognosis.

BACKGROUND: Retroperitoneal fibrosis (RPF) is a rare disease characterized by the presence of inflammatory and fibrous retroperitoneal tissue that often encircles abdominal organs including the aorta and ureters. Data on the incidence of this disease are limited. SUMMARY: The disease may be idiopathic or secondary to infections, malignancies, drugs, or radiotherapy. The idiopathic form is an immune-mediated entity and a part of the broader spectrum of idiopathic diseases termed chronic periaortitis, characterized by a morphologically similar fibroinflammatory changes in the aorta and surrounding tissues. Taking into account the dominant symptoms and clinical characteristics of patients with periaortitis, 2 subtypes of disease could be distinguished. The vascular subtype includes patients with nondilated aorta or with inflammatory abdominal aortic aneurysm, both with and without involvement of adjacent structures and with numerous risk factors for atherosclerosis. In the renoureteral subtype, obstructive uropathy manifesting with hydronephrosis and acute kidney injury is the predominant finding. Due to the variety of symptoms, diagnosis of RPF remains challenging, difficult, and often delayed. A series of diagnostic tests should be performed, in order to confirm the diagnosis idiopathic RPF. Laboratory workup includes evaluation of inflammatory indices and immunological studies. A biopsy and histopathological evaluation may be necessary to confirm diagnosis and differentiate the disease. Computed tomography, magnetic resonance imaging, and positron emission tomography are the modalities of choice for the diagnosis and follow-up of this disease. Management of ureteral obstruction, hydronephrosis, and aortic aneurysms often requires surgical evaluation and treatment. The pharmacological treatment of RPF has been evaluated in a few randomized trials and is mainly based on observational studies. Steroid therapy remains the gold standard of treatment. KEY MESSAGES: Nowadays, multidisciplinary team approach with clinical and diagnostic experience in both primary and secondary RPF as well as 2 major subtypes should be offered. Centers specialized in rare diseases with collaboration with other units and referral system yield the best possible outcomes.

IgG4-related retroperitoneal fibrosis: a rare cause of obstructive uropathy.

Immunoglobulin G4 (IgG4)-related disease was described in 2003 and is known to affect almost all organ systems. Rarely, this disease can manifest in the retroperitoneum, which can lead to sequalae such as obstructive uropathy. Here we describe a case of IgG4-related retroperitoneal fibrosis leading to obstructive uropathy. The patient was managed with bilateral Double J (DJ) stenting and oral steroids. Following remission of the disease, the DJ stents were removed and the patient remained asymptomatic over the follow-up period. A high index of suspicion is required for diagnosis of this rare disease and timely management can lead to a positive outcome.