IgG4-related kidney disease complicated with retroperitoneal fibrosis:A case report

BACKGROUND IgG4-related disease(IgG4-RD)is a chronic fibrotic disease mediated by immunity recognized by clinicians in recent years.When the kidney is involved,it is called IgG4-related kidney disease(IgG4-RKD).IgG4-related tubulointerstitial nephritis(IgG4-TIN)is a representative manifestation of IgG4-RKD.IgG4-TIN can cause obstructive nephropathy complicated by retroperitoneal fibrosis(RPF).Cases of IgG4-TIN complicated with RPF are rare.Glucocorticoids are the firstline therapeutic medication for IgG4-RD and can significantly improve renal function.CASE SUMMARY Herein,we report the case of a 56-year-old man with IgG4-RKD complicated with RPF.The patient presented to the hospital with complaints of elevated serum creatinine(Cr),nausea,and vomiting.During hospitalization,Cr was 1448.6μmol/L,and serum IgG4 was increased.A total abdominal computed tomography(CT)scan and enhanced CT scan obviously indicated RPF.Although this patient had a long course and renal insufficiency,we performed a kidney biopsy.Renal biopsy showed that the renal tubulointerstitium had focal plasma cell infiltration and increased lymphocyte infiltration accompanied by fibrosis.After combining the biopsy results with immunohistochemistry,it was found that the absolute number of positive IgG4+cells per high power field exceeded 10,and the ratio of IgG4/IgG was over 40%.Finally,the patient was diagnosed with IgG4-TIN complicated with RPF and given glucocorticoids as long-term maintenance therapy,helping him keep out of dialysis.After a follow-up of 19 mo,the patient had recovered well.Previous literature on IgG4-RKD and RPF was retrieved from PubMed to characterize the clinical and pathological features and to identify the diagnosis and treatment of IgG4-RKD.CONCLUSION Our case report demonstrates the clinical characteristics of IgG4-RKD complicated with RPF.Serum IgG4 is a favorable indicator for screening.Performing renal biopsy actively plays a vital role in diagnosis and treatment,even if the patient has a long course and manifests with renal insufficiency.It is remarkable to treat IgG4-RKD with glucocorticoids.Hence,early diagnosis and targeted therapy are essential for reversing renal function and improving extrarenal manifestations in patients with IgG4-RKD.

A Case of Acute Renal Failure Associated with IgG4-Related Disease Presenting Both Tubulointerstitial Nephritis and Retroperitoneal Fibrosis

We report a case of IgG4-related disease presenting both tubulointerstitial nephritis and retroperitoneal fibrosis causing acute renal failure in a 63-year-old male. He was admitted to our hospital because of acute renal failure requiring emergent hemodialysis. Computed tomography showed a soft-tissue density mass with an irregular border in the retroperitoneum. The mass involved bilateral ureters and had caused acute renal failure by bilateral hydronephrosis. Because of a history of uveitis and high IgG4 levels, we considered a diagnosis of retroperitoneal fibrosis, IgG4-related disease. Kidney biopsy revealed IgG4-related kidney disease with interstitial nephritis. After relief of urinary obstruction by inserting ureteral catheters into the bilateral ureters, renal function recovered.

Differentiation of Lymphoma Presenting as Retroperitoneal Mass and Retroperitoneal Fibrosis： Evaluation with Multidetector-row Computed Tomography

Background： Retroperitoneal fibrosis （RPF） and lymphoma presenting as retroperitoneal mass may closely resemble each other and misdiagnosis may occur. This study investigated the differential imaging features of RPF and lymphoma which presented as a retroperitoneal soft tissue using multidetector-row computed tomography （MDCT）. Methods： The 42 consecutive patients were included in this retrospective review, including 19 RPF patients （45.2%; including 13 males and 6 females; mean age： 56.7 ± 6.2 years） and 23 patients with lymphoma （54.8%： including 14 males and 9 females： mean age： 57.4 ± 12.3 years）. An array of qualitative computed tomography （CT） features of lesions in 42 consecutive patients with newly diagnosed untreated RPF and lymphoma were retrospectively analyzed. The quantitative size of the lesion at the para-aortic region and attenuation in the precontrast, arterial, and portal phases were calculated in regions of interest and compared between the patients with newly diagnosed untreated RPF and with lymphoma. Receiver operating characteristic curve analysis was used to assess the potential diagnostic value of each quantitative parameter. Inter-reader concordance was also calculated. Results： Mean ages between patients with RPF and lymphoma were not significantly different （56.7 ±6.2 years vs. 57.4 ± 12.3 years P = 0.595）. Compared to those in patients with lymphoma, homogeneous enhancement （65.2% vs. 94.7%, P = 0.027） and pelvic extension （52.2% vs. 89.5%, P= 0.017） were significantly more common while the involvement of additional nodes （78.3% vs. 5.3%, P 〈 0.001）, suprarenal extension （60.9% vs. 15.8%, P = 0.004）, and aortic displacement （43.5% vs. 5.3%, P 0.006） were significantly less common in patients with RPF. Lesion size at the para-aorta was significantly greater in patients with lymphoma, compared with RPF patients （3.9 ± 1.2 cm vs. 1.8 ± 0.6 cm; P 〈 0.001 ）. The attenuation values in three phases were not significantly different between patients with RPF and lymphoma. Inter-reader concordance for subjective features ranged from very good to excellent （range： 85.7 100.0%）. Conclusions： This study showed that MDCT can help differentiate between untreated RPF and lymphonla on the basis of qualitative CT features and lesion sizes. Differentiating RPF from lymphoma on the basis of attenuation values in the precontrast, arterial, and portal phases was difficult to accomplish.

Metallic ureteral stent in restoring kidney function: Nine case reports

BACKGROUND Retroperitoneal fibrosis is an exceptionally rare disease characterized by proliferation of fibrous tissue and inflammation in the retroperitoneum.It features many symptoms in the kidneys and in other organs and usually leads to ureteral obstruction.CASE SUMMARY Here we present 9 consecutive cases of idiopathic retroperitoneal fibrosis(IRPF)in patients who presented to the Department of Nephrology or Department of Rheumatology,Xuanwu Hospital,Capital Medical University,Beijing,China,between January 2012 and June 2017 with ureteral obstruction due to external compression of the ureter that led to hydronephrosis and kidney dysfunction.Computed tomography imaging was used to identify hydronephrosis and ureteral obstruction and to evaluate kidney function.Each patient was diagnosed with IRPF based on clinical observation and computed tomography examination results.To restore kidney function,a retrograde metallic stent was placed in the ureter under X-ray guidance 2 d after each patient’s admission.No perioperative complications occurred in any patient,but postoperative complications occurred in two patients as follows:Patient 2 had stent migration and repeated metallic stent infections that resolved with treatment;and patient 4 had postoperative hematuria because he resumed normal activities too soon after stent placement(contrary to instruction).Placement of the metallic ureteral stents provided relief from ureteral obstruction and restored kidney function in all patients.CONCLUSION Our 9-case series underscores the utility and efficacy of applying the Resonance®metallic ureteral stent to treat ureteral obstruction in patients with IRPF.For all retroperitoneal fibrosis cases in our series,ureteral stents provided effective relief and were shown to reduce the incidence rate of perioperative and postoperative complications.