The more common tumors generate prolactin, which causes, in women, loss of the normal menstrual cycle and production of breast secretions. These tumors are called prolactinomas . This is called Cushing's disease . A third hormone secreting tumor causes excessive production of growth hormone. This is called acromegaly .
Rare tumors can cause excess thyroid hormone.
There are specific symptoms that relate to each of these tumors. The second manner of presentation relates to increasing size of the tumor. These are usually tumors that do not cause hormone secretion. These tumors can get to be rather large and cause visual problems. The most common is the loss of peripheral vision.