Was it a proper pituitary MRI? Was it done dynamically with a experienced tech?
You did not indicate the size of the tumor in 2007 but smaller tumors can *fall between the slices*, the radiologist can miss them or they can change.
From my own experience, my prolactin levels were elevated, and then went down to normal but a dynamic MRI finally picked it up. When I had surgery (for a different secreting pituitary tumor), that tumor was confirmed to be a prolactinoma. But it only showed up on one of maybe 12 MRIs total.
Other hormones can elevate prolactin as well such as thyroid - so make sure you still get a good hormone check.
All I do know is that hormones are crazy and that if your prolactin went down on its own it would make sense that it shrunk. The meds are supposed to control your prolactin and hopefully shrink the tumor so it would make sense.
Dear Chrisdoc9270
I agree with Rumpled, She is an expert.
Furthermore, I have seen 3Tesla MRI with more artefacts than the 1.5 tesla MRIs for pituitary gland. That happens because of the air in the sphenoid sinus. Bottom line: you should have it repeated in a 1.5 tesla MRI with dynamic protocol. It may still be there.
Having said that: I did have a good number of patients with lesions in the pituitary gland that disappeared. Usually the tumor suffers apoplexy (infarct or bleeding) and dies. But it needs to be well evaluated before that conclusion.