Isn't that imposibble when you're on prednisone? I know I've got cushing symptoms as side effect, and if I taper I get addison like symptomes.

No, that is not impossible. Adenomas can happen when you are immunosuppressed, either adrenal or pituitary. With your situation, it's important to think of every possibility. A pituitary tumor can excrete too much ACTH, thereby increasing cortisol. An adrenal tumor can excrete cortisol on its own.

I hope that isn't going on. But something is.

Didn't know that. I'll write it down.

What do you mean by "but something is"?
As far as I understand, I have a somewhat refractory MG, which is a possibility (meaning not all MG gets better / in remission).

Sorry, didn't mean to sound mysterious! At least in my experience, there is usually a reason why MG is worse, whether that is activity versus rest, drug versus disease, an undiagnosed condition, an overactive immune system, a kink in biochemistry, or whatever. For healthy people without disease, they can do anything, eat junk food, loose sleep, etc. and not be affected. But with those of us with a disease, even the slightest variation from "pampering" or the right diet or whatever will push our immune system to be worse.

That's why I thought a journal of your daily symptoms, along with activities, food, etc. might help. It may not, but it's worth a try. So is finding more help.

Annie