Prolactinoma

National Endocrine and Metabolic Diseases Information Service
What is a prolactinoma?
A prolactinoma is a benign—noncancerous—
tumor of the pituitary gland that produces a hormone called prolactin. Prolactinomas are U.S. Department
of Health and
the most common type of pituitary tumor. Human Services
hyperprolactinemia—too much prolactin in NATIONAL
the blood—or by pressure of the tumor on INSTITUTES
OF HEALTH
Prolactin stimulates the breast to produce milk during pregnancy. After giving birth, a mother’s prolactin levels fall unless she breastfeeds her infant. Each time the baby nurses, prolactin levels rise to maintain milk What is the pituitary gland?
The pituitary gland, sometimes called the
master gland, plays a critical role in regulat­ and reproduction. It produces prolactin and The pituitary gland sits in the sella turcica. The pituitary gland sits in the middle of the head in a bony box called the sella turcica. The optic nerves sit directly above the pitu­ itary gland. Enlargement of the gland can cause symptoms such as headaches or visual What causes prolactinoma?
impair production of one or more pituitary hormones, causing reduced pituitary func­ largely unknown. Most pituitary tumors are sporadic, meaning they are not genetically How common is
What else causes prolactin
prolactinoma?
Although small benign pituitary tumors are fairly common in the general population, In some people, high blood levels of pro­ lactin can be traced to causes other than Prescription drugs. Prolactin secretion in
the pituitary is normally suppressed by the What are the symptoms of
brain chemical dopamine. Drugs that block prolactinoma?
the effects of dopamine at the pituitary or deplete dopamine stores in the brain may In women, high levels of prolactin in the cause the pituitary to secrete prolactin. blood often cause infertility and changes in menstruation. In some women, periods may medications such as trifluoperazine (Stela­ stop. In others, periods may become irregu­ zine) and haloperidol (Haldol); the newer antipsychotic drugs risperidone (Risperdal) who are not pregnant or nursing may begin (Reglan), used to treat gastroesophageal experience a loss of libido—interest in sex. Intercourse may become painful because of cancer drugs; and less often, verapamil, alpha–methyldopa (Aldochlor, Aldoril), and reserpine (Serpalan, Serpasil), used to lactinoma is erectile dysfunction. Because control high blood pressure. Some antide­ pressants may cause hyperprolactinemia, but changes in menstruation to signal a problem, many men delay going to the doctor until Other pituitary tumors. Other tumors
they have headaches or eye problems caused arising in or near the pituitary may block by the enlarged pituitary pressing against nearby optic nerves. They may not recognize the prolactin-secreting cells. Such tumors a gradual loss of sexual function or libido. include those that cause acromegaly, a condi­ Only after treatment do some men realize they had a problem with sexual function. and Cushing’s syndrome, caused by too much cortisol. Other pituitary tumors that do not Hypothyroidism. Increased prolactin levels
How is prolactinoma
are often seen in people with hypothyroid­ treated?
ism, a condition in which the thyroid does The goals of treatment are to return prolac­ Doctors routinely test people with hyperpro­ tin secretion to normal, reduce tumor size, correct any visual abnormalities, and restore normal pituitary function. In the case of Chest involvement. Nipple stimulation also
large tumors, only partial achievement of can cause a modest increase in the amount of prolactin in the blood. Similarly, chest wall injury or shingles involving the chest wall Medical Treatment
normally inhibits prolactin secretion, doc­ How is prolactinoma
tors may treat prolactinoma with the dop­ diagnosed?
amine agonists bromocriptine (Parlodel) or cabergoline (Dostinex). Agonists are drugs A doctor will test for prolactin blood levels that act like a naturally occurring substance. in women with unexplained milk secretion, called galactorrhea, or with irregular menses prolactin levels to normal in approximately or infertility and in men with impaired sexual function and, in rare cases, milk secretion. If prolactin levels are high, a doctor will test Administration for the treatment of hyper­ thyroid function and ask first about other prolactinemia. Bromocriptine is the only conditions and medications known to raise dopamine agonist approved for the treat­ prolactin secretion. The doctor may also ment of infertility. This drug has been in request magnetic resonance imaging (MRI), use longer than cabergoline and has a well- which is the most sensitive test for detecting pituitary tumors and determining their size. MRI scans may be repeated periodically to assess tumor progression and the effects of effects of bromocriptine. To avoid these side effects, bromocriptine treatment must scan also gives an image of the pituitary but be started slowly. A typical starting dose is one-quarter to one-half of a 2.5 milligram (mg) tablet taken at bedtime with a snack. The dose is gradually increased every 3 to surrounding tissues and perform tests to 7 days as needed and taken in divided doses assess whether production of other pituitary with meals or at bedtime with a snack. Most hormones is normal. Depending on the size people are successfully treated with 7.5 mg of the tumor, the doctor may request an eye a day or less, although some people need mocriptine is short acting, it should be taken those used for prolactinomas, heart valve endocrinologist—a doctor specializing in disorders of the hormone-producing glands. people taking low doses of cabergoline to Prolactin levels rise again in most people treat hyperprolactinemia. Before starting these medications, the doctor will order an however, prolactin levels remain normal, so the doctor may suggest reducing or discon­ sonogram of the heart that checks the heart tinuing treatment every 2 years on a trial Because limited information exists about the risks of long-term, low-dose cabergoline more effective than bromocriptine in nor­ use, doctors generally prescribe the lowest malizing prolactin levels and shrinking tumor effective dose and periodically reassess the size. Cabergoline also has less frequent and need for continuing therapy. People taking less severe side effects. Cabergoline is more cabergoline who develop symptoms of short­ ness of breath or swelling of the feet should newer on the market, its long-term safety promptly notify their physician because these record is less well defined. As with bro­ mocriptine therapy, nausea and dizziness are possible side effects but may be avoided if treatment is started slowly. The usual start­ Surgery to remove all or part of the tumor ing dose is .25 mg twice a week. The dose should only be considered if medical therapy may be increased every 4 weeks as needed, cannot be tolerated or if it fails to reduce up to 1 mg two times a week. Cabergoline prolactin levels, restore normal reproduction should not be stopped without consulting a and pituitary function, and reduce tumor size. If medical therapy is only partially Recent studies suggest prolactin levels are successful, it should be continued, possibly more likely to remain normal after discon­ tinuing long-term cabergoline therapy than Most often, the tumor is removed through the nasal cavity. Rarely, if the tumor is large research is needed to confirm these findings. or has spread to nearby brain tissue, the surgeon will access the tumor through an mocriptine to treat Parkinson’s disease The results of surgery depend a great deal How does prolactinoma
on tumor size and prolactin levels as well as affect pregnancy?
the skill and experience of the neurosurgeon. The higher the prolactin level before surgery, If a woman has a small prolactinoma, she the lower the chance of normalizing serum prolactin. Serum is the portion of the blood pregnancy after effective medical therapy. If used in measuring prolactin levels. In the she had a successful pregnancy before, the best medical centers, surgery corrects pro­ chance of her having more successful preg­ lactin levels in about 80 percent of patients with small tumors and a serum prolactin less A woman with prolactinoma should discuss than 200 nanograms per milliliter (ng/ml). her plans to conceive with her physician A surgical cure for large tumors is lower, at so she can be carefully evaluated prior to 30 to 40 percent. Even in patients with large tumors that cannot be completely removed, include an MRI scan to assess the size of the drug therapy may be able to return serum tumor and an eye examination with measure­ prolactin to the normal range—20 ng/ml or ment of visual fields. As soon as a woman is less—after surgery. Depending on the size pregnant, her doctor will usually advise her of the tumor and how much of it is removed, to stop taking bromocriptine or cabergoline. studies show that 20 to 50 percent will recur, Although these drugs are safe for the fetus in early pregnancy, their safety throughout an Because the results of surgery are so depen­ entire pregnancy has not been established. dent on the skill and knowledge of the neu­ Many doctors prefer to use bromocriptine rosurgeon, a patient should ask the surgeon about the number of operations he or she because it has a longer record of safety in has performed to remove pituitary tumors and for success and complication rates in The pituitary enlarges and prolactin produc­ comparison to major medical centers. The tion increases during pregnancy in women best results come from surgeons who have prolactin-secreting tumors may experience such operations. To find a surgeon, con­ further pituitary enlargement and must be tact The Pituitary Society (see For More closely monitored during pregnancy. Less than 3 percent of pregnant women with small Radiation
growth such as headaches or vision problems. Rarely, radiation therapy is used if medical In women with large prolactinomas, the risk therapy and surgery fail to reduce prolactin of symptomatic tumor growth is greater, and levels. Depending on the size and location of the tumor, radiation is delivered in low doses over the course of 5 to 6 weeks or in a single high dose. Radiation therapy is effective Most endocrinologists see patients every Is osteoporosis a risk in
women with high prolactin
woman should consult her endocrinologist promptly if she develops symptoms of tumor changes, nausea, vomiting, excessive thirst or estrogen are at increased risk for osteoporo­ urination, or extreme lethargy. Bromocrip­ sis. Hyperprolactinemia can reduce estrogen tine or, less often, cabergoline treatment may production. Although estrogen production be reinitiated and additional treatment may may be restored after treatment for hyper­ be required if the woman develops symptoms How do oral contraceptives
and hormone replacement
calcium intake through diet or supplements therapy affect prolactinoma? hyperprolactinemia may want to have peri­
Oral contraceptives are not thought to con­
odic bone density measurements and discuss tribute to the development of prolactinomas, estrogen replacement therapy or other bone- although some studies have found increased strengthening medications with their doctor. medications. Because oral contraceptives may produce regular menstrual bleeding in women who would otherwise have irregular menses due to hyperprolactinemia, prolac­ menses are absent or irregular. Women with prolactinoma treated with bromocriptine or cabergoline may safely take oral contracep­ treated with medical therapy or surgery for prolactinoma may be candidates for estrogen Hope through Research
Points to Remember
Researchers are working to identify a gene or genes that may contribute to the develop­ ment of pituitary tumors, including sporadic tumors. They are also investigating certain side effects of long-term treatment for pro­ Participants in clinical trials can play a more active role in their own health care, gain access to new research treatments before they are widely available, and help others by contributing to medical research. For infor­ For More Information
American Association of Clinical
Endocrinologists
• The first line of treatment is usually The Endocrine Society
Phone: 1–888–363–6274 or 301–941–0200 The Pituitary Society
Acknowledgments
National Endocrine
and Metabolic Diseases
Information Service
tists and outside experts. This publication was reviewed by Michael O. Thorner, M.B., D.Sc., University of Virginia Health System, You may also find additional information about this topic by visiting MedlinePlus at www.medlineplus.gov. The National Endocrine and Metabolic Dis- This publication may contain information about eases Information Service is an information medications. When prepared, this publication included the most current information available. dissemination service of the National Insti- For updates or for questions about any medications, tute of Diabetes and Digestive and Kidney contact the U.S. Food and Drug Administration toll-free at 1–888–INFO–FDA (1–888–463–6332) or visit www.fda.gov. Consult your doctor for more the National Institutes of Health, which is part of the U.S. Department of Health and The U.S. Government does not endorse or favor any medical research. As a public service, the specific commercial product or company. Trade, proprietary, or company names appearing in this NIDDK has established information services document are used only because they are considered necessary in the context of the information provided. about health and disease among patients, If a product is not mentioned, the omission does not mean or imply that the product is unsatisfactory.
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