Prolactinomas are small, benign tumors that form just below the brain, in an organ called the pituitary gland. This means they are not cancerous. They are more common in women under the age of 50. These tumors can cause symptoms such as galactorrhea and amenorrhea in women, or reduced libido in men.
The pituitary gland contains various types of cells that produce different hormones, including prolactin. When prolactin-producing cells become abnormal and proliferate uncontrollably, prolactinomas develop.
Prolactinomas can cause symptoms in two ways:
- From the rise in prolactin itself
- From the pressure a prolactinoma exerts on neighboring structures near the pituitary gland as it grows—such as the nerves running from the eyes to the brain.
In premenopausal women, symptoms may include:
-Amenorrhoea or menstrual irregularities.
-Galactorrhea
-Subfertility
-Loss of bone mass.
Women after menopause do not have these symptoms.
In men, symptoms may include:
-Increased breast size and breast pain
-Low energy, low libido, and erectile dysfunction
-Subfertility
-Loss of bone mass
When a prolactinoma grows large enough, it can compress adjacent pituitary structures and cause other symptoms. These may include:
-Vision problems
-Headaches
-Lower levels of other hormones produced in the pituitary gland
These symptoms are more common in men than in women. This is because women are more likely to notice early symptoms—such as amenorrhea or menstrual irregularities—and seek treatment while the prolactinoma is still small.
The diagnosis of a prolactinoma includes:
- Blood test to measure prolactin levels
- Magnetic resonance imaging (MRI) of the pituitary gland
The treatment of a prolactinoma depends on its size and the patient’s symptoms.
In the majority of cases, treatment involves medication with dopamine agonists. These drugs can lower prolactin levels to the normal range and shrink prolactinomas.
When prolactin levels return to normal, most symptoms improve. If prolactin levels remain normal for several years and the prolactinoma is no longer visible on MRI, discontinuation of treatment may be recommended. In some people, prolactin levels may rise again after treatment is stopped.
In rare cases where the treatment is ineffective or causes significant side effects, surgical removal of the prolactinoma may be recommended.
If you are receiving treatment for a prolactinoma and have entered menopause, speak to your doctor. Some women can stop their treatment after menopause.
Information for women wishing to become pregnant
If you wish to become pregnant, speak to your doctor about the appropriate treatment for you.
Many women can become pregnant after starting treatment. Women receiving treatment stop using it as soon as they become pregnant.
Discontinuing the medication carries the risk that prolactinomas may enlarge. Fortunately, this does not happen very often.
If you develop vision problems while pregnant, it could be a sign that your prolactinoma has grown. This applies to women with very large prolactinomas. If you have a large prolactinoma, your doctor will ask you to undergo special vision tests. These tests are performed before you become pregnant and during each trimester of pregnancy.
Inform your doctor if you experience new or more severe headaches. Having headaches may indicate that your prolactinoma has grown.