What Causes Prolactinoma?

Prolactinoma is a mostly benign pituitary tumor that develops from prolactin-secreting cells in the pituitary gland. The pituitary gland is a small endocrine gland located at the base of the brain and plays an important role in regulating many hormones in the body. When a prolactinoma develops, the level of prolactin hormone in the blood rises above normal. This condition may cause menstrual irregularities, milk discharge, and pregnancy-related problems in women, while in men it may lead to decreased sexual desire, erectile problems, and low testosterone levels.

The question of what causes prolactinoma is one of the most frequently asked questions by patients who receive this diagnosis. However, in most patients, a single and definite factor responsible for the development of the tumor cannot be identified. Prof. Dr. Ömür Günaldı emphasizes that hormone levels, pituitary MRI images, and the patient’s clinical symptoms should be evaluated together when assessing prolactinoma.

How Does Prolactinoma Develop?

Prolactinoma develops as a result of the uncontrolled proliferation of prolactin-producing cells in the pituitary gland. Under normal conditions, prolactin production is suppressed by dopamine secreted in the brain. Dopamine reaches the pituitary gland and prevents excessive production of prolactin.

When prolactinoma develops, the number of prolactin-secreting cells increases and hormone production may escape normal control mechanisms. As a result, the prolactin level in the blood rises.

Cellular Changes May Play a Role

In the development of prolactinoma, changes may occur in certain cellular mechanisms that control the growth and proliferation of pituitary cells. These changes may cause prolactin-producing cells to multiply more than normal.

However, it is not always possible to determine clearly why these cellular changes begin in every patient. Most prolactinoma cases occur without any obvious environmental or lifestyle factor.

Can Prolactinoma Develop Due to Genetic Causes?

Most prolactinomas are not hereditary. However, in rare cases, the risk of pituitary tumors may increase together with certain genetic disorders.

MEN1 Syndrome

Multiple Endocrine Neoplasia Type 1, or MEN1 syndrome, is an inherited disorder that creates a predisposition to tumor development in certain endocrine organs. Pituitary tumors may occur in MEN1 syndrome, and some of these tumors may present as prolactinomas.

Genetic evaluation may be considered in patients whose family includes more than one person with a pituitary tumor, parathyroid disease, or pancreatic endocrine tumors.

Familial Pituitary Tumors

The likelihood of developing prolactinoma may also increase in some rare familial pituitary tumor syndromes. Therefore, patients who develop the disease at a young age, have large tumors, or have a family history of similar conditions may require a more detailed evaluation.

Prof. Dr. Ömür Günaldı states that especially in patients with suspected familial pituitary tumors, not only imaging findings but also family history should be evaluated.

Can Hormonal Imbalances Cause Prolactinoma?

Prolactinoma and high prolactin levels should not be confused with one another. Not every elevated prolactin level means that a prolactinoma is present.

Prolactin levels may increase for many different reasons. Pregnancy, breastfeeding, stress, certain medications, thyroid disorders, and kidney failure may increase prolactin levels.

However, these conditions do not directly cause prolactinoma. Therefore, when elevated prolactin is detected, the underlying cause should be identified correctly.

Hypothyroidism and High Prolactin

Hypothyroidism, defined as an underactive thyroid gland, may cause an increase in prolactin levels. In this situation, the cause of elevated prolactin may be a thyroid hormone disorder rather than a pituitary tumor.

For this reason, thyroid function tests are generally also evaluated in patients with elevated prolactin.

Can Medications Cause Prolactinoma?

Certain medications may increase prolactin levels in the blood. In particular, some psychiatric medications that reduce dopamine activity, anti-nausea medications, and certain other drug groups may cause hyperprolactinemia.

However, these medications generally do not cause a true prolactinoma. It is important to distinguish between medication-related prolactin elevation and prolactinoma.

For this reason, a detailed evaluation of the medications used by the patient is important. Medications should not be discontinued without a doctor’s recommendation.

Can Stress Cause Prolactinoma?

Intense physical or psychological stress may temporarily increase prolactin levels. Even stress experienced during a blood draw may raise prolactin levels in some people.

However, there is no strong scientific evidence showing that stress directly causes prolactinoma.

In patients with mildly elevated prolactin levels, the test may need to be repeated under appropriate conditions. Prof. Dr. Ömür Günaldı emphasizes that prolactin elevation should not be evaluated based on a single laboratory result and that it should be interpreted together with the patient’s clinical findings.

Why Is Prolactinoma Detected More Frequently in Women?

Prolactinoma can occur in both women and men. However, it may be detected earlier, especially in women of reproductive age.

The main reason is that elevated prolactin can cause early symptoms such as menstrual irregularities and milk discharge from the breasts in women.

In men, symptoms may initially be milder. Decreased sexual desire, low testosterone levels, or erectile problems may develop over time. For this reason, in some male patients, the tumor may be diagnosed only after it has reached a larger size.

What Are the Types of Prolactinoma?

Prolactinomas are divided into different groups according to their size.

Microprolactinoma

Prolactinomas smaller than 10 millimeters in diameter are called microprolactinomas. They may be especially common in women.

Macroprolactinoma

Tumors that are 10 millimeters or larger in diameter are called macroprolactinomas. Large tumors may put pressure on surrounding structures.

Tumors that grow close to the optic nerves may cause narrowing of the visual field or other vision problems.

What Are the Symptoms of Prolactinoma?

Symptoms of prolactinoma may occur due to both elevated prolactin levels and the size of the tumor.

Symptoms that may be seen in women include menstrual irregularities, absence of menstruation, milk discharge from the breasts, difficulty becoming pregnant, and decreased sexual desire.

In men, reduced testosterone levels, decreased sexual desire, erectile problems, infertility, and in some cases enlargement of breast tissue may occur.

Large prolactinomas may also cause headaches and vision problems.

How Is Prolactinoma Diagnosed?

One of the first steps in diagnosing prolactinoma is measuring the prolactin level in the blood. If the prolactin level is found to be elevated, other conditions that may be causing the elevation are investigated.

Thyroid function tests, medications being used, and other hormonal values are evaluated.

Pituitary MRI is generally used to visualize the pituitary gland. MRI allows the size and location of the tumor, as well as its relationship with surrounding tissues, to be examined in detail.

Prof. Dr. Ömür Günaldı states that evaluating hormone tests together with MRI findings is important for an accurate prolactinoma diagnosis.

Can Prolactinoma Be Treated?

Prolactinoma is one of the pituitary tumors that responds very well to medication treatment in many patients. Drugs known as dopamine agonists are generally used in treatment.

These medications may reduce prolactin levels and help shrink the tumor.

In some situations where medication treatment is insufficient, the patient cannot tolerate the medication, or the tumor causes significant pressure on surrounding structures, surgical treatment may be considered.

Whether surgery is required is evaluated according to the patient’s age, hormone levels, tumor size, symptoms, and response to treatment.

Why Does Prolactinoma Occur?

It is not possible to give a single answer to the question of what causes prolactinoma for every patient. In most cases, it is not known exactly why the prolactin-producing cells in the pituitary gland begin to multiply uncontrollably.

In rare cases, genetic predisposition and certain familial endocrine disorders may play a role. Apart from these, stress, medication use, and thyroid disorders may increase prolactin levels, but these conditions alone do not mean that a prolactinoma is present.

People with elevated prolactin levels or suspected pituitary tumors should be evaluated by endocrinology specialists and, when necessary, neurosurgeons. During the neurosurgical evaluation performed by Prof. Dr. Ömür Günaldı, the size and location of the tumor, its hormonal effects, and the pressure it exerts on surrounding tissues can be assessed together to determine an appropriate treatment approach for the patient.

This content is for general informational purposes only and does not replace personal diagnosis or treatment advice.