Prof. Pietro MORTINI

A prolactinoma is a type of pituitary tumor (adenoma) that produces an excessive amount of the hormone prolactin. Prolactinomas are the most common type of hormonally-active pituitary tumor.


The symptoms caused by a prolactinoma depend upon several factors, including gender and age. Prolactinomas are rare in children; when they occur, they may cause headache and weight gain.

Prolactinoma symptoms in premenopausal women:

It is unusual for a prolactinoma to progress to a large size in premenopausal women. If it does grow in size, it may cause hypopituitarism, visual losses and headache.

Prolactinoma symptoms in men and postmenopausal women

Men and postmenopausal females do not have menstrual periods, so the effects of elevated prolactin often go unnoticed. In men particularly, prolactinomas may remain undiagnosed for years.

Symptoms in men include:

Prolactinomas in men are often very large, and may invade structures adjacent to the normal pituitary gland.

Symptoms Related to Large Tumor Size (Macroadenomas)

A macroadenoma is a large pituitary tumor (10 mm or larger). Large tumors can compress surrounding structures, primarily the normal pituitary gland and optic (visual) pathways, causing symptoms.

The symptoms that result from the compression are independent of the effects of excess growth hormone secretion.

Often, prolactinomas in men and postmenopausal women are discovered when the tumor grows large enough to compress surrounding structures. This causes symptoms including:


diagnostic procedures include:

Hormone Testing for Prolactinomas

A blood test measures the level of prolactin, which is essential for establishing a diagnosis. A very high level indicates a prolactinoma, whereas a mildly elevated level may indicate:

Certain medications and conditions may mildly elevate prolactin levels, and therefore must be considered before making the diagnosis of prolactinoma:

Prolactinoma Diagnosis: Accuracy of Laboratory Testing

Diagnosing a prolactinoma requires special care, expertise and specialized laboratory equipment. An experienced pituitary tumor team understands the nuances of the diagnostic procedure. We will occasionally need to run extra tests and procedures if there are concerns about the results.

MRI Imaging for Prolactinomas

Most prolactinomas can be detected using Magnetic Resonance Imaging (MRI) of the pituitary gland. We use a special MRI pituitary protocol in order to best visualize the tumor.

Treatment Options

The optimal treatment of a prolactinoma depends on multiple factors, including:

Treatment options include:

Medical Therapy for Prolactinomas

Medication is the first line of treatment for a prolactinoma. Your doctor will prescribe a medication that mimics the effects of dopamine, the brain chemical that normally inhibits the release of prolactin by the pituitary gland. The two most commonly prescribed medications are:

About 75 percent of patients respond to medical therapy, with a noticeable reduction in tumor size:

Sometimes, the tumor does not respond to medication, or you cannot tolerate the medicine, perhaps due to unwanted side effects. In this case, your doctor may recommend surgical removal of the tumor.

Optimal medical treatment of prolactinomas often requires escalation of drug dosing, and therefore endocrinologists with special training in pituitary tumor management (neuro-endocrinologist) are involved in the care.

Medical Therapy: Fertility and Pregnancy Concerns

The management of medical therapy for fertility and during pregnancy requires special consideration. It is important to discuss conception, fertility and pregnancy considerations with your endocrinologists.

Surgery for Prolactinomas

You may be a candidate for surgery if you did not respond to medical treatment. You may be a candidate if you experienced:

Most neurosurgeons specializing in pituitary tumor surgery use the minimally invasive endoscopic technique.

In experienced hands, the endoscopic approach:

This advanced technique requires specialized training and equipment and should be performed at a dedicated pituitary tumor center.

Radiation Therapy for Prolactinomas

Some tumors cannot be removed surgically, and may not respond to medications. Radiation therapy can be effective in controlling the growth of these tumors.

In some of these cases Stereotactic Radiosurgery can be used. This carefully sculpted radiation beam is able to deliver a high dose of radiation to the target. The surrounding brain structures receive only a fraction of the radiation and are typically unharmed, with the exception of the pituitary gland.

A consequence of radiation treatment is that it can cause delayed pituitary failure. This typically occurs several years after treatment. It is important that you continue your follow-up care with an endocrinologist, who can monitor your progress and any changes. You may require hormone replacement therapy.

Acromegaly     Non-Functioning Pituitary Adenomas     Cushing Disease     TSH-oma