Prolactinomas are the most common hormone-secreting pituitary tumors. It is a noncancerous (benign) pituitary tumor that produces a hormone called prolactin. This results in too much prolactin in the blood. These occur most commonly in people under age 40. They are about five times more common in women than in men, but are rare in children. Larger tumors are more common in men. They tend to occur at an older age. The tumor can grow to a large size before symptoms appear.
Symptoms: Women will have absent or irregular menstrual periods,women who are not pregnant or breastfeeding frequently experience a milky breast discharge. Breast discharge (galactorrhea) can occur in men, but is much less common than in women.