Eric F. H. van Bommel

Background Idiopathic retroperitoneal fibrosis (iRPF) is a rare chronic fibro-inflammatory disorder of unknown etiology. Activated T-helper cells, which shed soluble interleukin-2 receptor (sIL-2R) into the circulation, may play a pathogenetic role. Hence, measuring sIL-2R may be of value in monitoring disease activity and treatment response in iRPF patients. Methods We performed a prospective inception cohort study of 82 patients with untreated (re)active iRPF stratified by elevated (> 623 U/mL) or normal sIL-2R level at baseline and compared disease characteristics among these groups. Baseline and changes in sIL-2R levels following treatment with tamoxifen (TMX) or prednisone (PDN) were analyzed and related to treatment response. Results Median sIL-2R level was 668 U/mL (IQR 502.8–827.5); 48 patients (59%) had elevated baseline sIL-2R levels. Patients with elevated sIL-2R presented with higher CRP (P = 0.049) and serum creatinine (sCr) levels (P < 0.001) and more often had hydroureteronephrosis (P = 0.01). There was an age and sex adjusted linear association between baseline sIL-2R and both CRP (P = 0.02) and sCr (P < 0.001). Baseline and serial levels of sIL-2R were predictive and concordant, respectively, with clinical response in patients treated with PDN. ROC curve analyses of sIL-2R on a continuous scale and PDN treatment success showed an AUC of 0.84. A serum sIL-2R cut-off value for PDN treatment success of ≤ 703 U/mL was found with a sensitivity of 100% and specificity of 72%. Conclusion Serial measurement of sIL-2R may be of value in monitoring disease activity and PDN treatment response in iRPF patients.

Although much debated, an exaggerated inflammatory response to advanced atherosclerosis has been implicated in the pathogenesis of idiopathic retroperitoneal fibrosis (RPF). Clinical presentation, infrarenal abdominal aortic diameter and RPF mass thickness were retrospectively analyzed in 166 patients with idiopathic RPF seen at our referral center between April 1998 and December 2019. Patients were stratified to their infrarenal abdominal aortic diameter at presentation (i.e., non-ectatic [< 25 mm]; ectatic [25–29 mm]; and aneurysmal [≥ 30 mm]) to compare characteristics across groups with an undilated or dilated aorta. Ectatic or aneurysmal aortic dilatation was present in 34% of patients. Most clinical characteristics did not differ across abdominal aortic diameter stratified groups, but RPF mass thickness was greater in patients presenting with aortic aneurysmal dilatation compared to that in patients with an undilated aorta (49.0 mm [IQR 34.0–62.0] vs 32.5 mm [IQR 25.3–47.8]; P < 0.001). A positive linear association was found between aortic diameter on a continuous scale and RPF mass thickness (β 0.32 [95% CI 0.34–0.96]; P < 0.001). This association remained significant after adjusting for age, sex and acute-phase reactant levels (β 0.28 [95% CI 0.15–0.95]; P < 0.01). Treatment success across aortic diameter stratified groups did not differ (P = 0.98). Treatment induced RPF mass regression was not associated with an increase in aortic expansion rate (P = 0.44). Aortic dilatation was prevalent among patients. Infrarenal abdominal aortic diameter was independently associated with RPF mass thickness. Findings support the concept that at least in a subset of patients, RPF may be secondary to advanced atherosclerosis.

Case: Retroperitoneal fibrosis (RPF) is a rare chronic fibroinflammatory disorder with typically unknown etiology (i.e., idiopathic). However, several causes have been identified, including retroperitoneal injury or inflammation. In this study, we describe 2 patients who developed RPF complicated by hydroureteronephrosis after (combined) anterior lower interbody fusion (ALIF) and posterior spine fusion. We also reviewed 6 additional cases from the literature of suspected RPF development after spinal surgery. In these cumulative 8 cases, ALIF was the common denominator. Conclusion: RPF may develop after ALIF and should be considered a potential longer term complication of this procedure.

Summary: We present a rare case of intimal angiosarcoma arising from the iliac artery with unusual symptoms and signs mimicking retroperitoneal fibrosis (RPF). This 84-year-old male presented with constitutional symptoms, abdominal pain, increased acute-phase reactant levels, impaired renal function and a CT-documented left-sided parailiac soft-tissue mass with unilateral extrinsic ureteric obstruction. Whole-body 18F-fluorodeoxyglucose positron emission tomography scan showed highly increased FDG-uptake in a horseshoe-like pattern surrounding the left common iliac artery, but no pathologic activity elsewhere. Further diagnostic workup revealed no signs of malignancy. Because of its location, CT-guided biopsy of the mass was precluded. A tentative diagnosis of RPF was made and treatment with Tamoxifen 20 b.i.d. was started. However, his condition gradually deteriorated, eventually succumbing to severe pneumosepsis. Autopsy revealed extensive iliac intimal angiosarcoma with infiltrative expansion to the left ureter and tumor emboli in both lungs. The present case suggests that intimal angiosarcoma should be included in the differential diagnosis of suspected RPF.

Aims Retroperitoneal fibrosis (RPF) is a rare chronic fibro‐inflammatory disorder that may be secondary to certain drugs, including β‐blocking agents (BBAs). However, their causative role is unclear. We aimed to investigate this association. Methods Disproportionality analysis was carried out on cases from 1985 to 4 October 2020 in VigiBase, the World Health Organization pharmacovigilance database. The Bayesian‐based IC₀₂₅ metric and reporting odds ratio were used in order to assess the adverse event signal. We also analysed all published case reports from the literature regarding BBA‐associated RPF to assess the value of suggested supportive clinical evidence. Results In total, 1599 individual case safety reports of RPF were reported to VigiBase, of which 132 (32%) concerned 16 different single BBA. For 12 of these agents (75%), reporting of RPF was disproportionate, indicating a potential safety signal. Line listing analysis of individual case safety reports showed no consistent time interval from start of BBA to RPF diagnosis (range 0.7–264 mo). Dechallenge was negative or unknown in the majority of cases (74%). In 18 published cases from the literature, time from start of BBA to RPF diagnosis varied widely (range 3–156 mo). BBA were discontinued 6 months before (n = 1) or at the time of RPF diagnosis (n = 17). Most patients (84%) also received RPF specific treatment. Follow‐up duration was short (median 5 mo [range 1–24 mo]) and in most cases (83%) relevant follow‐up data were lacking. Conclusion Although disproportionality analysis indicated a potential safety signal for RPF associated with BBAs, clinical evidence did not support a cause‐and‐effect relationship.

The overall objective of these guidelines is to provide evidence‐based recommendations for the diagnosis and management of immunoglobulin G4 (IgG4)‐related digestive disease in adults and children. IgG4‐related digestive disease can be diagnosed only with a comprehensive work‐up that includes histology, organ morphology at imaging, serology, search for other organ involvement, and response to glucocorticoid treatment. Indications for treatment are symptomatic patients with obstructive jaundice, abdominal pain, posterior pancreatic pain, and involvement of extra‐pancreatic digestive organs, including IgG4‐related cholangitis. Treatment with glucocorticoids should be weight‐based and initiated at a dose of 0.6–0.8 mg/kg body weight/day orally (typical starting dose 30‐40 mg/day prednisone equivalent) for 1 month to induce remission and then be tapered within two additional months. Response to initial treatment should be assessed at week 2–4 with clinical, biochemical and morphological markers. Maintenance treatment with glucocorticoids should be considered in multi‐organ disease or history of relapse. If there is no change in disease activity and burden within 3 months, the diagnosis should be reconsidered. If the disease relapsed during the 3 months of treatment, immunosuppressive drugs should be added.

Erdheim–Chester Disease (ECD) is a rare, non-Langerhans histiocytosis, characterized by the accumulation of foamy macrophages, chronic inflammation, fibrosis and organ failure [1,2]. Interferon alf...

Idiopathic retroperitoneal fibrosis (iRPF) may be a manifestation of IgG4-related disease. Measuring serum IgG4 (sIgG4) may be of value in monitoring iRPF, but this has scarcely been evaluated. It is unknown if tamoxifen (TMX) affects sIgG4 levels. We performed a prospective inception cohort study of 59 patients with untreated (re)active iRPF stratified by elevated (>1.4 g/L) or normal sIgG4 level. Changes in sIgG4 levels following TMX initiation and, if treatment failed, during subsequent corticosteroid (CS) treatment were analyzed. The median sIgG4 level was 1.1 g/L (interquartile range (IQR) 0.4–2.2); 24 patients (40%) had elevated sIgG4 level. Patients with elevated sIgG4 tended to present with higher ESR (46 vs. 34 mm/h; P = 0.08) and more frequent locoregional lymphadenopathy adjacent to the mass (41.7 vs. 20.0%; P = 0.08). sIgG4 also correlated with ESR (ρ = 0.26; P = 0.05) and serum creatinine (SC) (ρ = 0.26; P = 0.04). Following TMX initiation, sIgG4 level decreased, particularly when achieving treatment success (P < 0.01). Odds ratio for TMX treatment success in patients with elevated sIgG4 level was 0.77 (95% CI 0.53–1.14; P = 0.19). After adjusting for age, sex, and SC, the odds ratio was 0.78 (95% CI 0.51–1.18; P = 0.24). ROC curve analyses of sIgG4 on a continuous scale and treatment success showed an AUC of 0.62. Treatment success and concurrent sIgG4 decrease (P < 0.01) were achieved in 78% of patients who converted to CS therapy. Patients with elevated sIgG4 level may be more inflammatory than patients with normal sIgG4 level, but this needs further study. TMX affects sIgG4 levels, but to a lesser extent than CSs. sIgG4 cannot be used as an outcome prediction tool, irrespective of which cutoff value was chosen.