P148 Clinical & radiological profile of 24 cases of retroperitoneal fibrosis diagnosed between 2008 and 2018 in England

Abstract Background/Aims Retroperitoneal fibrosis (RPF) is a rare fibroinflammatory disorder, with only a few international case series described. Urinary obstruction is the most common complication, requiring ureteric stenting or nephrostomy. Ureterolysis with omental wrap allows long-term ureteric patency after initial bypass stenting - this is a procedure offered by the Department of Urology at our centre since 2008. We describe the clinical and radiological profile, including medical and surgical treatment outcomes of RPF cases referred to the departments of Urology and Rheumatology of a tertiary centre in north England. Methods Electronic notes of RPF patients referred to Urology or Rheumatology, were reviewed for clinical data, radiological findings, monitoring and treatment outcomes. Results 24 RPF patients were referred to the departments of Urology and Rheumatology between 2008 and 2019. Six were under joint care between Urology and Rheumatology of our centre. The remaining 18 patients were managed by Urology of our centre and the local rheumatology, nephrology, vascular surgery, colorectal, gynaecology or urology services. 15 (62.5%) patients were male, while 9 (37.5%) were female. Median age at diagnosis was 54.5 years. Acute kidney injury was the most frequent presentation, in 91.7% of patients. Vascular involvement at presentation includes involvement of aorta (66.6%) and bowel (12.5%), accelerated hypertensive crises (8.3%) and incident deep vein thrombosis (DVT) (8.3%). Three (12.5%) cases were due to IgG4 disease. No secondary cause of malignancy was detected. CT detected RPF in all 24 patients. MAGs scans assessed individual kidney viability before ureterolysis. Five of eight PET scans detected activity metabolic activity. All 24 patients needed either double J-stenting or nephrostomy. Following nephrostomy, two cases had extra-anatomical stent instead of ureterolysis. 17 patients had ureterolysis. At follow up, 14 of these 17 (82.4%) patients remained free of stents or nephrostomy. Small treatment size suggested corticosteroid monotherapy and methotrexate to be poorly effective. Azathioprine was poorly tolerated, effective in four of seven patients. Rituximab was effective in a case of IgG4-related RPF. Long-term complications showed 70.8% of patients remained in GFR category G3a CKD, or worse, during follow up, and a total of five patients had DVT (20.8%). Aorto-arterial complications had also resulted in complex surgeries such as aneurysm repair, arterial bypass, mesenteric stenting and bowel resection. Five (20.8%) patients required nephrectomies. 41.7% of patients suffered from chronic pain. Conclusion RPF is associated with renal and aorto-venous complications, a variety of surgical morbidities and chronic pain. Multi-disciplinary care is necessary to address the multi-faceted complications and treatment strategy. In view of the varied organ complications and morbidities in this rare disease, a central registry data collection on investigation and treatment outcome is likely to be helpful to guide future management directions to reduce renal morbidity and aorto-venous complications. Disclosure E.P. Chua: None. R. Napier-Hemy: None. E.M. McCarthy: None. P. Ho: None.