What is your treatment algorithm for management of retroperitoneal fibrosis that does not respond to high-dose glucocorticoids?

There are a number of caveats to this.

1. Is the retroperitoneal fibrosis biopsy-proven and/or IgG4 disease ruled out?
2. If a case is refractory, I first question whether the diagnosis is correct and will often biopsy in this situation with more than an FNA biopsy. The second question is how long have t...