High-dose glucocorticoid treatment for non-IgG4-related idiopathic retroperitoneal fibrosis

IgG4: immunoglobulin G4; CT: computed tomography; MRI: magnetic resonance imaging; ESR: erythrocyte sedimentation rate; CRP: C-reactive protein; FDG-PET: 18F-fluorodeoxyglucose positron emission tomography.
* Improvement in ESR and CRP and, if applicable, serum creatinine may be noted but is not required to define response to therapy.
¶ The total duration of therapy may be varied between 6 months to over 1 year depending upon the severity of the disease (size and extent of the retroperitoneal mass) and the response to prednisone.