Prolactinomas are a type of pituitary adenoma that occurs in the prolactin cells of the pituitary gland and secretes the hormone prolactin. The primary role of prolactin in the body is to stimulate a woman’s breasts to make milk during and after pregnancy. However, men and women who aren’t pregnant also produce the hormone.

Prolactinomas are one of the most common types of pituitary tumors, accounting for 30 percent of all tumors found in the pituitary gland. The exact cause of prolactinomas is unknown. Men and women can develop a prolactinoma.

Prolactinoma Symptoms

In women, symptoms of a prolactinoma may include lactating breasts not associated with pregnancy, and irregular or absent periods.

In men, symptoms are less common, but may include discharge from the nipples, impotence, decrease in body hair, or erectile dysfunction.

Most prolactinomas do not grow large enough to cause other symptoms. However, larger tumors may cause headaches or problems with vision if the tumor compresses the nearby optic nerves.

Prolactinoma Diagnosis

Prolactinomas are diagnosed using blood tests that look for abnormal amounts of prolactin. 

You may also need to have an MRI scan of the brain, where the pituitary gland is located, to determine the exact size and location of the tumor.

Prolactinoma Treatment

More than 90 percent of people who develop a prolactinoma can be treated with medication alone. At Memorial Sloan Kettering, we usually prescribe cabergoline (Dostinex^®). The drug comes in pill form and is generally taken once or twice a week. Another medication that can be used to treat prolactinomas is bromocriptine.

Radiation Therapy for Prolactinomas

Radiation therapy can be used in several ways for a prolactinoma. It may be recommended as additional therapy after surgery to prevent regrowth of the tumor. Radiation may also be used as the sole treatment if the tumor cannot be removed surgically, or if the tumor regrows after surgery.

The radiation therapy team at MSK is highly experienced in caring for people with prolactinomas, and works closely with the other members of your care team. They have access to every form of modern radiation therapy available and will customize a treatment plan so precise that it factors in the size and shape of your tumor to the millimeter. 

Their goal is to not only eliminate the tumor cells but to prevent the side effects of treatment by keeping the healthy cells around the tumor safe.

We offer several radiation therapy options for people with a prolactinoma. Learn more about our approach to radiation therapy for pituitary tumors.

Prolactinoma Surgery

Surgery is not commonly used to treat a prolactinoma, but it is recommended in patients who develop significant side effects or who do not respond to the medication. Cabergoline is not approved for use during pregnancy, so women planning to conceive may also be candidates for surgery.

If surgery is necessary, Memorial Sloan Kettering surgeons are experienced in using a minimally invasive approach called transsphenoidal surgery to remove pituitary tumors. The approach allows our surgeons to bypass brain tissue, operating instead through an incision inside the nasal passage. The risk for neurologic complications with this technique is very low, and the surgery leaves no visible scar.