A prolactinoma is a tumor of the prolactin-producing cells of the pituitary gland. The pituitary gland, or master gland, lies at the bottom of the brain and controls growth, metabolism, and reproduction. One of the many hormones secreted by the pituitary is prolactin. Prolactin causes a woman’s breasts to secrete milk after pregnancy. Tumors in prolactin-secreting cells of the pituitary cause too much prolactin to get into the bloodstream.
Prolactinomas are rare and occur in 1 or 2 people in 10,000. Most are curable.
The cause is unknown.
Women may have changes in menstruation (periods) or produce milk when they aren’t pregnant. High prolactin levels may lower estrogen levels, which lead to vaginal dryness and painful intercourse.
Males may notice impotence or lower sex drive.
Untreated prolactinomas may lead to reduced amounts of mineral in bones (osteoporosis). Tumors may also press on nerves near the pituitary, such as optic nerves, which are important for vision. The result may be decreased peripheral vision.
The health care provider diagnoses a prolactinoma by finding high blood prolactin levels. Breast stimulation will also increase prolactin levels, as will many drugs, especially antidepressants. People with hypothyroidism (low thyroid gland function) or advanced liver or kidney disease can also have high prolactin levels. The health care provider will take into account medicines you are taking and other medical disorders when making the diagnosis.
Magnetic resonance imaging (MRI) of the brain will show a tumor in the pituitary gland.
The best treatment depends on symptoms and tumor size. The treatment goal is to have normal reproductive and pituitary function and minimize symptoms, such as production of breast milk and changes in periods.
Some people with very small tumors (called microadenomas), who have no symptoms may be followed up with annual MRI and prolactin level tests. Many of these small prolactinomas don’t get larger.
People with symptoms need medicine (e.g., bromocriptine and cabergoline) to shrink the tumor and reduce prolactin levels.
If medicine isn’t tolerated or doesn’t control tumor growth, surgery is used and can be very successful. But tumors may come back after surgery. Larger tumors (macroadenomas) can be treated with surgery, irradiation of the pituitary, and medications. The tumor may also be destroyed with radiation delivered through multiple ports (stereotactic surgery, also called gamma knife surgery).
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Copyright © 2016 by Saunders, an imprint of Elsevier, Inc.
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