What is prolactinoma?

A sort of prolactinoma Usually a noncancerous (benign) pituitary tumor that causes the body to produce too much milk-producing hormone Prolactin. This can lead to different symptoms in women and men, ranging from menstrual irregularities in women to erectile dysfunction in men.

The pituitary gland is located in the brain. It produces hormones related to growth and reproduction, etc.

In addition to prolactin, it also produces follicle-stimulating hormone (FSH) and luteinizing hormone (LH). In women, these are associated with stimulating the body to produce eggs and regulating the menstrual cycle. In men, pituitary hormones cause the release of testosterone and stimulate sperm production.

Types of Prolactinomas

Generally, prolactinomas come in two size categories—small and large. Most are less than three-eighths of an inch in diameter and are called microprolactinomas. These are more likely to affect women. Larger, large prolactinomas measuring more than three-eighths of an inch in diameter are less common. These tend to affect men.


Symptoms associated with this condition vary by gender. For people with a uterus and/or ovaries, signs of this condition include:

  • Menstrual cessation unrelated to other causes such as irregular periods or menopause
  • decreased sexual interest
  • Breast milk production in people who are not breastfeeding or pregnant
  • Infertility due to egg release disorder
  • headache
  • Vision problems and changes

Meanwhile, testicular patients with very small prolactinomas often face the following symptoms:

  • Erectile dysfunction (inability to achieve or maintain an erection large enough to penetrate)
  • decreased sexual interest
  • breast enlargement
  • fertility problems
  • Reduced peripheral vision or other vision changes
  • headache
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With larger prolactinomas, you’re more likely to have vision problems or headaches. The nerves associated with the eye can be compressed by the pituitary gland, which is just below these nerves.

Symptoms of these larger tumors may include:

  • headache
  • Ptosis, diplopia, areas of vision loss, and other vision changes
  • Nasal problems or olfactory disturbances related to drainage
  • nausea and vomiting
  • tired
  • sinus problems


Pituitary tumors like prolactinomas are often unrelated to genetic factors, but this can happen. These usually appear spontaneously for unknown reasons.

Of the hormone-producing pituitary tumors, prolactinomas are the most common. Prolactinomas produce prolactin, which is involved in milk production. In some cases, prolactinomas may be part of multiple endocrine neoplasia type 1 associated with endocrine tumors.

Prolactinomas are more common in women than men. In most cases, people with prolactinoma are younger than 40 years old, but this tumor is rare in children.


Your healthcare provider will take your medical history, ask you which drugs and substances you have used, and record your symptoms. Your doctor will then perform a physical examination. Tests that can be performed include imaging and blood tests.

Pituitary tumors can be found on magnetic resonance imaging (MRI) or computed tomography (CT) scans, with MRI being more commonly used.

Hormone levels will be checked with a blood test. If prolactin is 150–200 nanograms per milliliter (ng/ml), you may have a tumor that secretes prolactin. Stress or even just inserting a needle can slightly raise prolactin levels. To see if the levels are consistently high, multiple tests may be done.

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Your prolactin levels may also increase due to a condition called macroprolactinemia. With this, prolactin levels are elevated, but there are no clinical symptoms because prolactin’s interaction with blood proteins makes it inactive.

Other blood tests include testosterone levels, thyroid function tests to look for an underactive thyroid (which raises prolactin), and further tests of pituitary function.


Usually, treatment for prolactinoma involves taking drugs that mimic dopamine (the transmission of messages between nerves and brain cells), called dopamine agonists. These drugs are effective in reducing tumor size and prolactin levels in 80%–90% of people.

Typical dopamine agonists include:

  • Dostinex (cabergoline): This drug is usually given in 0.5 milligram (mg) doses, is persistent, and usually only needs to be taken up to twice a week. This has the fewest side effects and is usually the first drug prescribed.
  • Parlodel (bromocriptine): People taking this drug take 2.5 mg tablets 2 to 3 times a day. This is an older drug and is more likely to cause side effects such as dizziness, nausea and headaches.
  • Norprolac (quinagolide): This once-daily dose is gradually increased to 75 micrograms.

Prolactin levels usually return to normal within a few weeks of taking these drugs. As the levels decrease, a woman’s menstrual cycle usually resumes again, often restoring fertility as well as sex drive (sexual desire).

Likewise, drugs often shrink the tumor and relieve problems associated with it pressing on the nerve in the eye. If these effects are present, you may notice an improvement in your vision.

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While the drug is effective for most patients, about 5% of patients may find they are resistant to the drug. Likewise, another 5% may not be able to take it due to side effects.

In some of these cases, surgical removal of the tumor may be an option. Another possibility, if surgery is ruled out, is to use radiation therapy to target the tumor. In many cases, carefully targeted radiation can hone in on the tumor while sparing healthy surrounding tissue.


A prolactinoma is a usually noncancerous tumor of the pituitary gland that secretes large amounts of the hormone prolactin. This can lead to symptoms such as irregular periods, erectile dysfunction, breast enlargement and/or milk production, infertility, headaches and vision changes.

Prolactinoma tumors can be large or small. Symptoms are different for each type, and may also be different for women and men. Also, small tumors tend to be more common in women, while larger tumors are more common in men.

Treatment usually involves the use of drugs to mimic dopamine, which is effective in up to 90 percent of patients. But surgery or radiation therapy are also possible.

VigorTip words

Having a prolactinoma can bring a myriad of symptoms, from infertility to vision problems. Once the condition is diagnosed, it can usually be successfully treated with medication in just a few weeks. Additional treatments, such as surgical removal or the use of radiation, are only needed in rare cases.