[Long-term follow-up of a French cohort of retroperitoneal fibrosis]

Purpose: Retroperitoneal fibrosis (RPF) is a rare disease with an expanding etiologic spectrum. We aimed to analyze non-invasive diagnosis strategy, associated disorders, monitoring, treatment and prognosis.

Methods: Retrospective cohort study in a single tertiary center.

Results: Eighteen RPF cases (11 males) followed between 1996 and 2009 were reviewed. Blood CRP level was high in all cases before treatment. CT scan, associated or not with MRI or 18-FDG PET-scan, confirmed the diagnosis in 15 patients. Histological analysis of a surgical biopsy specimen was performed in only three cases. Ten patients suffered retroperitoneal fibrosis secondary to systemic vasculitis (granulomatosis with polyangeitis, n=1, Takayasu aortitis, n=2), systemic fibrosis with Riedel thyroiditis (n=1) and atheromatous periaortitis (n=6). Fifteen patients were treated with corticosteroids with a mean treatment duration of 60 months (12-228). Dependency to corticosteroids was recorded in ten patients. Patients with fibrosis related to vasculitis were younger, had a higher CRP level, more frequent corticosteroid dependency and a higher relapse rate. Relapses were successfully treated with steroids. Immunosuppressive treatment was only prescribed in the setting of systemic vasculitis. No patient died, after a 6±2 years follow-up. Late relapses could occur, sometimes years after steroid therapy cessation.

Conclusion: In our study, RPF occurred as a secondary disorder in 60% of the cases. Disease extension, relapse rate and treatment response varied according to the underlying cause of RPF, pleading for an extensive and systematic initial assessment. Since no death or end-stage renal insufficiency was observed, RPF might be considered as a steroid-sensitive and benign disorder.