Prolactinoma

Dr. med. Mira Seidel is a freelance writer for the medical team.

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The prolactinoma is a benign tumor of the pituitary gland, which produces a large amount of the hormone prolactin. As a result, the testes and ovaries are not stimulated enough, which impairs their function. Typical symptoms are absenteeism in women and impotence in men. The prolactinoma is usually successfully treated with drugs or, in rare cases, surgically. You can find out more about the prolactinoma here.

ICD codes for this disease: ICD codes are internationally recognized codes for medical diagnoses. They can be found, for example, in doctor's letters or on certificates of incapacity for work. D35

Prolactinoma: description

The prolactinoma is the most common tumor of the pituitary gland. It causes the hypohysis to release more of the hormone prolactin. A prolactinoma can occur in both men and women. Most often, a prolactinoma develops in women younger than 50 years of age.

Depending on the size of the tumor, one speaks of a microprolactinoma (diameter less than ten millimeters) or macroprolactinoma (diameter greater than ten millimeters). Most prolactinomas fall into the first category, that is, they are smaller than ten millimeters. In addition, they are mostly benign; Malignant prolactinomas are very rare.

The hormone prolactin

Prolactin plays an important role in reproductive health in women, and blood prolactin levels are increased during pregnancy and while breastfeeding. In pregnant women, the hormone is responsible for ensuring that the mammary glands develop and grow. It also stimulates the cells in the mammary glands to produce milk. When the baby sucks on the nipple, this stimulates the small muscle cells of the mammary gland - milk comes out.

During breastfeeding, the high level of prolactin can suppress ovulation and thus prevent a new pregnancy during breastfeeding. The decisive factor, however, is how often and for how long the child is breastfed. Breastfeeding is by no means a reliable method of contraception.

Prolactinoma: symptoms

Prolactinoma can cause symptoms in two ways:

It produces a lot of prolactin, which affects the way other hormones work.
It grows and displaces neighboring tissue such as nerves that lead from the eye to the brain.

A prolactinoma leads to disturbances of the sexual function in men as well as in women before menopause. Postmenopausal women have no symptoms of prolactinoma because the ovaries have already stopped working.

Prolactinoma: symptoms in premenopausal women

A high prolactin level in women of childbearing age inhibits ovulation, which leads to irregular or even no menstruation (amenorrhea). About 10 to 20 percent of women who fail to menstruate have excessively high prolactin levels. Because of the menstrual cycle disorders, women with a prolactinoma also have difficulty getting pregnant. Other symptoms include a dry vagina and hot flashes.

The prolactinoma also stimulates milk production and secretion. About 24 percent of women with high levels of prolactin leak small amounts of milk from their breasts (galactorrhea) even though the woman is not pregnant or breastfeeding.

Another symptom is osteoporosis. Especially with long-term prolactinoma, those affected have a lower bone density.

Prolactinoma: symptoms in postmenopausal women

In postmenopausal women, prolactinoma does not show any symptoms. This is because prolactin can no longer influence the cycle. Affected women only notice a prolactinoma when it has become so large that it affects neighboring tissue and thus causes headaches or visual disturbances. However, it can also be discovered purely by chance if the head is examined with an imaging method (magnetic resonance tomography, MRT) for another reason.

Prolactinoma: symptoms in men

In men, too, the prolactinoma causes a prolactin level that is too high and inhibits the gonads, in this case the testicles. As a result, they produce less sperm and testosterone, the most important sex hormone in men. Typical symptoms are a loss of libido, impotence, infertility and listlessness.

Potency disorders and loss of libido are the first early symptoms of a prolactinoma. In some cases, breast enlargement (gynecomastia) and spontaneous milk flow (galactorrhea) may also occur. However, this is more common in women because the man's mammary glands are less sensitive to prolactin.

If the prolactinoma has existed for a long time, the muscle mass can decrease. Pubic hair and beard growth can also recede. As in women, bone mass also decreases in men. A long-standing prolactinoma can lead to osteoporosis.

Macroprolactinoma causes other symptoms

If the prolactinoma becomes larger than a centimeter and thus becomes a macroadenoma, it can press on neighboring structures in the brain. Often the optic nerve comes under pressure, which leads to visual disturbances. In most cases, those affected have bilateral visual field defects. In some cases, however, only one eye can be affected.

The pressure exerted by the prolactinoma on the pituitary gland can affect the production of other hormones in the gland, such as hormones from the thyroid gland or the adrenal cortex. This leads to the fact that the function of the organs concerned is reduced.

The pressure of the tumor on brain structures can also cause headaches.

Prolactinoma: causes and risk factors

The prolactinoma consists of altered cells in the pituitary gland (pituitary gland), a hormonal gland just below the cerebrum. More precisely, the prolactinoma develops from cells in the anterior pituitary gland (adenohypophysis). The pituitary gland has different cells that produce different hormones. The so-called lactotrophic cells produce the hormone prolactin.

A prolactinoma occurs when a lactotrophic cell mutates and begins to divide uncontrollably. This ultimately creates a large mass of altered cells, all of which produce prolactin - the prolactin level rises. About 10 percent also produce growth hormone in addition to prolactin.

Usually a prolactinoma develops without an apparent cause. In rare cases it develops as part of a hereditary disease, multiple endocrine neoplasia type 1 (MEN 1).

Prolactinoma: examinations and diagnosis

There are various tests that can be used to detect a prolactinoma. The specialist responsible for suspected prolactinoma is an endocrinologist, a specialist in hormonal balance. The doctor will first record the medical history (anamnesis). For example, he asks the following questions:

Are you pregnant?
Are you taking estrogens or certain medications such as risperidone, metoclopramide, antidepressants, cimetidine, methyldopa, reserpine or verapamil?
Do you suffer from a headache?
Do you have visual disturbances? If so, what kind?
Are you sensitive to the cold, listless or tired?

The doctor will then do a physical exam. He will examine you for visual disturbances such as visual field defects, signs of hypothyroidism and estrogen or testosterone deficiency.

As a next step, the doctor will order a blood sample to measure the prolactin level. The blood test should be done at least one to two hours after waking up, as the prolactin level is higher during sleep than when awake.

In the case of a prolactinoma, the measurement result can range from slightly increased prolactin to a thousand-fold increased prolactin. In general, larger prolactinomas cause higher levels of prolactin. Prolactin levels above 250 micrograms per liter (µg / l) are more likely to be a prolactinoma. The findings should then be confirmed with magnetic resonance imaging (MRI, also known as magnetic resonance imaging) of the head. However, very small prolactinomas (microadenomas) are not always visible on MRI.

Other causes of high levels of prolactin

An increased prolactin level (hyperprolactinemia) is not always necessarily due to a prolactinoma. In addition to stress and other illnesses, certain drugs can also cause high prolactin levels, for example so-called dopamine antagonists such as metoclopramide (for nausea and vomiting) or some active ingredients for the treatment of mental illnesses (such as antidepressants, neuroleptics).

Prolactinoma: treatment

Not every prolactinoma needs treatment. If it is very large or causes symptoms, treatment is advisable. In the case of small prolactinomas that show no symptoms, treatment can also be dispensed with. Doctor and patient will work together to weigh the benefits and risks of the treatment options.

Medication

If treatment is necessary, the prolactinoma usually responds very well to the administration of so-called dopamine agonists. These are drugs that have a similar effect in the body as the body's own messenger substance dopamine. In this way, dopamine agonists can lower the prolactin level and shrink the prolactinoma or even make it disappear completely.

It usually takes about two to three weeks for your prolactin levels to drop. However, the prolactinoma usually takes a few weeks to months to shrink. If the tumor affects the visual field, the visual impairment usually improves a few days after the start of treatment.

Dopamine agonists usually need to be taken for a few years. The prolactin levels are continuously monitored during this time.

In the case of a prolactinoma, the following dopamine agonists can be given:

Bromocriptine

Bromocriptine has been used to treat prolactinoma for about 30 years. It is taken twice a day and works very effectively by lowering prolactin levels quickly. However, bromocriptine can cause many side effects: People complain of dizziness, nausea and a stuffy nose. However, many of the side effects can be prevented by taking the drug before meals or at bedtime.

Cabergoline

Cabergoline is only taken once or twice a week and causes fewer side effects. It can lower prolactin levels by around 90 percent and is therefore the therapy of choice. However, it is not recommended for women trying to get pregnant.

Drug treatment during pregnancy

During pregnancy, the pituitary gland doubles in size to produce more prolactin - the hormone is important for milk production. This can be particularly dangerous for women with a macroprolactinoma. Anyone who has a prolactinoma and would like to have a child should therefore speak to an endocrinologist about treatment before becoming pregnant. Among other things, the following questions need to be clarified:

When should dopamine agonist therapy be stopped?
What is the risk of prolactinoma growing during pregnancy?
What are the treatment options if the prolactinoma grows again?
Can I breastfeed my child afterwards?

If you have vision problems or headaches during pregnancy, these may be a sign that the prolactinoma has grown back. In order to be able to recognize this early on, an eye test is carried out every month. Most women can get pregnant normally after treatment for prolactinoma.

Surgical treatment

If the patient does not respond to dopamine agonists, the prolactinoma must be surgically removed. For a woman with a very large macroprolactinoma, surgery is the treatment of choice. The risk that the prolactinoma will continue to grow during a possible pregnancy is too great in this case.

During the operation, the prolactinoma is removed through the nose. The surgeon uses an endoscope, a long, thin instrument that is equipped with a light source and a camera.

The increased prolactin values usually drop immediately after the operation, sometimes even to the normal value in the case of microadenomas.

radiotherapy

Radiation therapy is only rarely used, when drug and surgical therapy measures have not shown sufficient success. Radiation can shrink the prolactinoma and lower blood prolactin levels. However, the therapy often only shows its full effect after years and also has many side effects such as nausea, tiredness, loss of taste and smell and hair loss. In addition, half of patients who have received radiation therapy will develop pituitary dysfunction with low blood levels of pituitary hormones within ten years.

Prolactinoma: disease course and prognosis

In the case of a microprolactinoma, a normal prolactin level can almost always be achieved through drug therapy with dopamine agonists. If an operation is necessary, even with a small prolactinoma, this usually leads to normal prolactin levels in the long term. However, a relapse can occur later. This also applies to a large prolactinoma (macroprolactinoma).

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