Treatment of retroperitoneal fibrosis with rituximab, cyclophosphamide and dexamethasone, followed by rituximab and dexamethasone maintenance, achieved disappearance of pathological PET accumulation of FDG and regression of fibrotic masses after 4 mo

Treatment of retroperitoneal fibrosis with the tripple combination of rituximab, cyclophosphamide and dexamethasone achieved a very rapid disappearance of pathological FDG accumulation and fibrotic retroperitoneal mass, with complete disappearance achieved after 4 months of treatment. After 3 years of maitenance therapy, the diesease is still in complete remission on PET/MR examination. We suggest to continue the maintenance therapy with rituximab because of some increase in the number of circulating plasmablasts after prolongation of the intervals between rituximab administration.