A prolactinoma is a benign tumor of the pituitary gland that produces the hormone prolactin. Prolactin is the hormone that is responsible for signaling a woman's body to produce milk after she has had a baby.

Prolactinomas can be various sizes. Most are less than half an inch in diameter.


The symptoms are usually caused by higher levels of prolactin in the blood. Symptoms may also be caused by the pressure of the tumor on surrounding tissues, glands and nerves.
The most common symptoms are absence of menstrual periods and abnormal production of breast milk. Other symptoms may include reduced sex drive, impotence, vaginal dryness, infertility, headaches, disturbed vision, brittle bones (osteoporosis), mood changes and depression.

Causes and Risk Factors

Prolactinomas can occur in both men and women.


Prolactinomas can be diagnosed on the basis of the symptoms they produce and a blood test to measure prolactin levels in the blood. Additional tests such as computed tomography scans or magnetic resonance imaging scans may be needed to identify and locate the tumor.


Few people with prolactinomas need surgery. Most prolactinomas - especially the small ones - shrink with treatment with medication. Sometimes radiation may be used to help shrink the tumor.

© 2000-2022 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.
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