Dr. M.J. Bazos, MD. Patient Handout
About Your Diagnosis
A prolactinoma is a tumor of the prolactin-producing cells of the pituitary gland. The pituitary gland, or master gland, sits at the base of the brain and regulates normal growth, metabolism, and reproduction. One of the many hormones secreted by the pituitary is prolactin. Prolactin is the hormone that causes a woman’s breasts to secrete milk after pregnancy. If a tumor develops in the prolactin-secreting cells of the pituitary, too much prolactin is secreted into the bloodstream. One or two individuals in 10,000 will have a
prolactinoma. There is no known genetic link for this disorder. A prolactinoma is detected by measuring prolactin levels in the blood. It is important that patients are not taking certain medicines such as reserpine, alpha-methyldopa, metoclopramide, haloperidol, or trifluoperazine because prolactin levels could be falsely elevated. Prolactin levels may also be falsely elevated in patients with hypothyroidism or advanced kidney disease. The diagnosis is confirmed by obtaining a magnetic resonance imaging (MRI) scan of the pituitary gland. Most prolactinomas are completely curable with medication or surgery.

Living With Your Diagnosis
Women may have changes in their menses, or have milk production when they are not pregnant. Elevated prolactin levels may decrease estrogen levels, leading to vaginal dryness and painful intercourse. Males may only notice impotence or decreased sex drive. Untreated prolactinoma could lead to decreased bone mineral density or osteoporosis. It may also compress local nerves near the pituitary such as the optic nerves, which are important for vision. This causes a decrease in peripheral vision.

The best treatment for a prolactinoma depends on the extent of the patient’s symptoms as well as the extent of the tumor. The goal of treatment is to restore normal reproductive and pituitary function, as well as to minimize symptoms such as breast milky discharge and change in menstrual periods. Some patients with microadenomas of less than 10 mm who have no symptoms of their disease may be followed up clinically with annual MRI scans of the pituitary and annual prolactin levels. The vast majority of prolactinomas of this size do not progress to larger tumors. Medication is required for symptomatic patients. Bromocriptine increases dopamine secretion from the hypothalamus, which leads to decreased prolactin levels and tumor shrinkage in most patients. Bromocriptine, 1.25 mg, is taken once at night with food for several days; the dose is then slowly increased until prolactin levels are normal or side effects, such as nausea or dizziness, become intolerable. Cabergoline is a newer longer-acting medication which may be better tolerated than bromocriptine. If medical therapy is not tolerated or fails to control the growth of the prolactinoma, then surgery is required. This also has a very high success rate if the prolactinoma is identified early. Tumors may recur postoperatively. Complications of surgery include bleeding, infection, leaking cerebrospinal fluid (CSF), and hypopituitarism (an underactive pituitary) requiring hormone replacement.
The DOs
• Make sure your prolactin level was measured while you were fasting for at least 8 hours, and that there has not been recent breast stimulation.
• Obtain follow-up images of the pituitary to prove the prolactinoma is not growing.
• Start with a low dose of medication and increase the dose slowly.
• Find an experienced neurosurgeon if you require surgery for your prolactinoma. Success rates are highly dependent upon the experience and skill of the neurosurgeon.
The DON’Ts
• Don’t give up on your medicine if you are having mild side effects. Instead, decrease your dose by one pill a day, and increase again 1 week later.
• Don’t forget to use appropriate birth control if you are sexually active after beginning treatment for your prolactinoma. Women with irregular menstrual periods or men with low testosterone levels will have normalization of their reproductive status with treatment of their prolactinoma.
When to Call Your Doctor
• You experience any change in your vision.
• You have an unusual increase in headaches.
• You have nausea or dizziness as a result of the medicine.
• You are feeling excessively weak and tired or are urinating frequently after prolactinoma surgery.
The National Institute of Diabetes and Digestive and Kidney Diseases