These tumors make prolactin, a hormone that stimulates a woman's breasts to make milk during and after pregnancy. They are the most common type of pituitary tumor, accounting for some 30 percent of pituitary adenomas. Prolactin-secreting microadenomas are most often found in women in their 30s, while macroadenomas are equally common in men and women.
Symptoms
Prolactinomas can cause the breasts to make milk and cause menstrual periods to stop when a woman is not pregnant. In men, prolactinomas can cause impotence. Large prolactinomas may cause vision disturbances by pressing on the nearby optic nerve.
Diagnosis
If your doctor suspects a prolactinoma, a blood test may be ordered to measure your prolactin levels. MRI may also be used to visualize the tumor.
Treatment
Some 80 to 90 percent of prolactinomas can be treated using medication alone. Cabergoline (Dostinex) is a long-acting drug taken in pill form, and it typically needs to be taken once a week.
Surgery is sometimes used to reduce tumor size in patients with large prolactinomas, especially if the tumor is causing vision loss. Surgery for pituitary tumors is often performed through a minimally invasive approach called transphenoidal hypophysectomy, whereby the surgeon removes the tumor through an incision in the nasal passage. In cases where the tumor is too large to be removed through this approach, the surgeon performs a craniotomy, removing the tumor through an incision in the front of the skull.
Follow-Up
Your doctor will see you periodically and perform certain tests to ensure that your pituitary tumor has not returned. If medication is part of your treatment, you may need to take it for the rest of your life to prevent tumor recurrence.
