I developed a prolactinoma after starting HRT. A few months in, my prolactin levels rose, and my endocrinologist ran a second blood test to confirm. She then sent me for an MRI, which showed a 3mm growth in my pituitary gland.
Here's the important part: she did not stop my HRT. In fact, I did not even have to fight her about that. She didn't consider it an option because HRT was so important to my mental well being. Instead, she treated me like a natal female. Prolactinomas are fairly common among women starting in their thirties and fourties. The small ones (under 10mm) are very successfully treated with a class of drugs called dopamine agonists. Dopamine is the natural enemy of prolactin production, and these drugs raise dopamine levels and shrink the tumors. I have been on one of these drugs (cabergoline) for a bit more than a month now, and I've already noticed that certain sexual problems, often caused by high prolactin levels, have subsided.
So yes, you can take HRT and treat a prolactinoma at the same time. No one would dream of cutting off estrogen in a natal woman to fight one of these tumors. Why should we be any different? If your endocrinologist tells you otherwise, try finding a new one.
