Patient education: Prolactinoma (The Basics)

What are prolactinomas? — Prolactinomas are abnormal growths that form right below the brain, in an organ called the "pituitary gland" (figure 1). These growths can cause symptoms, such as absent monthly periods in females or low sex drive in males.

The pituitary gland has different cells in it that make different hormones. Some of the cells in the pituitary gland make a hormone called "prolactin."

A prolactinoma forms when these cells change into abnormal cells and grow out of control. When that happens, the body's prolactin levels can get too high.

Prolactinomas can cause symptoms in 2 ways. Symptoms can happen when:

●A person has too much prolactin – This can throw off the levels of other hormones.

●A prolactinoma grows and presses on nearby parts inside the head, such as the nerves that go from the eyes to the brain

Prolactinomas are most common in females younger than 50 years old. Prolactinomas are a type of "benign" growth. This means that they are not cancer.

What are the symptoms of a prolactinoma? — Too much prolactin can cause symptoms.

In females who still get a monthly period, symptoms can include:

●Absent or irregular monthly periods

●Milk leaking from the breasts

●Trouble getting pregnant

●Bone loss – This takes a few years to happen.

People who have been through menopause and no longer get a monthly period do not get these symptoms.

In males, symptoms can include:

●Increased breast size and breast soreness

●Low energy, low sex drive, and trouble getting an erection

●Trouble getting a partner pregnant

●Bone loss – This takes a few years to happen.

When a prolactinoma grows large enough to press on nearby parts, it can cause other symptoms. These can include:

●Vision problems

●Headaches

●Lower levels of other hormones that are made in the pituitary gland

These symptoms are more common in males than in females. That's because females are more likely to notice early symptoms, like absent or irregular periods, and get treatment while the prolactinoma is still small.

Is there a test for a prolactinoma? — Yes. Your doctor or nurse can do:

●A blood test to measure the level of prolactin in your body

●MRI – This is an imaging test that creates pictures of the pituitary gland.

How are prolactinomas treated? — Although prolactinomas are benign (not cancerous), they usually still need to be treated. They are treated in different ways, depending on their size, the symptoms they cause, and other factors.

Prolactinomas are first treated with medicines called "dopamine agonists." These medicines can lower prolactin levels to normal and shrink big prolactinomas. When the prolactin levels get back to normal, most symptoms get better. If prolactin levels have been normal for a couple of years and the prolactinoma seems to be gone, some doctors stop the dopamine agonist. Some people have to go back on the medicine because the prolactin level goes back up again. But sometimes, the prolactin level doesn't go back up. When this happens, you can stay off of the medicine.

If these medicines do not work or cause too many side effects, there are other treatment options. These can include:

●Surgery to remove the prolactinoma

●Other types of medicines

What if I want to get pregnant? — If you want to get pregnant, talk with your doctor about the right treatment for you. Many people are able to get pregnant after treatment.

People who take dopamine agonist medicines stop taking them once they get pregnant. But without these medicines, their prolactinomas can start to grow. Luckily, this does not happen very often. If you have a large prolactinoma, your doctor might recommend surgery to remove it before you start trying to get pregnant.

If you develop vision problems while you are pregnant, it could be a sign that your prolactinoma has grown. This is only a problem with very large prolactinomas. If you have a large prolactinoma, your doctor will have you do special vision tests. These tests are done before you get pregnant, and then again every 3 months.

Tell your doctor or nurse if you have any new or worse headaches. Having headaches could mean that your prolactinoma has grown.

What if I go through menopause? — If you are being treated for a prolactinoma and go through menopause (when monthly periods stop), talk with your doctor or nurse. Some people can stop their treatment after menopause.

More on this topic

Patient education: Female infertility (The Basics)
Patient education: Male infertility (The Basics)
Patient education: Pituitary adenoma (The Basics)
Patient education: Sex problems in males (The Basics)
Patient education: Absent or irregular periods (The Basics)
Patient education: Osteoporosis (The Basics)

Patient education: High prolactin levels and prolactinomas (Beyond the Basics)