I appreciate your writing me about your 12 year old son who has Peritoneal Fibrosis. Mine started by wrapping around my small intestine and causing pain and nausea. Surgery to remove two sections of my small intestine was done and I am under the care of a Rhumatologist who prescribed Tamoxifen twice daily and prednisone (starting with 64 mg. I am now down to 4 mg. Cat scans show that it is keeping the fibrosis under control; however, there is no cure. I hope your son can be adequately treated and that he will not have any side effects. God bless you both!