hypothalamic-pituitary-adrenal axis,

When I was 17 I was diagnosed  with a brain tumor on or near the hypothalamus.I had three stereo tactic biopsies to try and find out what type of  tumor I had with no results, so I was put on high doses of   Dexamethasone to shrink it but all that happened was I became cushingoid.  I then had  radiotherapy which  shrunk it again but it came back after 3yrs , so then it was decided that I had a craniotomy biopsy, but still no Diagnosis the Surgeon said he thought it may be a  virus or an infection not a tumor. the sample was sent to John Radcliffe Oxford and Queen Elizabeth Birmingham hospitals in England and they could only tell us what it wasn't but not what it was.I am now 24yrs old and would like some closure on this, is it possible that some Hospital in America would be able to give me a diagnosis.All this has left me with a very bad short term memory loss and I take hydrocortisone,levothyroxine, desmopressin and  HRT.every day. I would be very grateful for any help and information you could give me. Thanks