I was diagnosed with retroperitoneal fibrosis. It is a fibrosis mass growing in the peritoneal cavity of my back. It can be life threatening or it can just sit there which is what mine is doing at this point. I was just wondering if anyone with FM or CFS has this? I have been told the conditions are not related but I really thought I could get more insight about it here than from my Drs. since they don't seem to know much about any of these conditions. I understand that this is a very rare thing and is more likely to happen to men. They have no idea why I have it....Anyone that knows anything about this...Please Help!!!!!! Mick!!