Overview

Prolactinoma is a noncancerous tumor of the pituitary gland. This tumor causes the pituitary to make too much of a hormone called prolactin. The major effect of prolactinoma is decreased levels of some sex hormones — estrogen in women and testosterone in men.

Although prolactinoma isn't life-threatening, it can cause vision difficulties, infertility and other problems. Prolactinoma is the most common type of hormone-producing tumor that can develop in your pituitary gland.

Doctors can often treat prolactinoma with medications to restore your prolactin level to normal. Surgery to remove the pituitary tumor also might be an option.

Symptoms

Prolactinoma might not cause any noticeable signs or symptoms. However, excessive prolactin in your blood (hyperprolactinemia) or pressure on surrounding tissues from a large tumor can cause signs or symptoms. Because elevated prolactin can disrupt the reproductive system (hypogonadism), some of the signs and symptoms of prolactinoma are specific to females or males.

In females, prolactinoma can cause:

  • Irregular menstrual periods or no menstrual periods
  • Milky discharge from the breasts when not pregnant or breast-feeding
  • Painful intercourse due to vaginal dryness
  • Acne and excessive body and facial hair growth

In males, prolactinoma can cause:

  • Erectile dysfunction
  • Decreased body and facial hair
  • Enlarged breasts, uncommonly

In both sexes, prolactinoma can cause:

  • Low bone density
  • Reduction of other hormone production by the pituitary gland as a result of tumor pressure
  • Loss of interest in sexual activity
  • Headaches
  • Visual disturbances
  • Infertility

Women tend to notice signs and symptoms earlier than men do, when tumors are smaller in size, probably because of missed or irregular menstrual periods. Men tend to notice signs and symptoms later, when tumors are larger and more likely to cause headache or vision problems.

When to see a doctor

If you develop signs and symptoms associated with prolactinoma, see your doctor to determine the cause.

Causes

Prolactinoma is one type of tumor that develops in the pituitary gland. The cause of these tumors is unknown.

The pituitary gland is a small bean-shaped gland situated at the base of your brain. Despite its small size, the pituitary gland influences nearly every part of your body. Its hormones help regulate important functions such as growth, metabolism, blood pressure and reproduction.

Other possible causes of prolactin overproduction include medications, other types of pituitary tumors, an underactive thyroid gland, ongoing irritation to the chest, pregnancy and breast-feeding.

Risk factors

More prolactinomas occur in women than men. The disorder is rare in children.

Complications

Complications of prolactinoma may include:

  • Bone loss (osteoporosis). Too much prolactin can reduce production of the hormones estrogen and testosterone, resulting in decreased bone density and an increased risk of osteoporosis.
  • Pregnancy complications. During a normal pregnancy, the production of estrogen increases. If you are pregnant and have a large prolactinoma, these high levels of estrogen may cause tumor growth and associated signs and symptoms, such as headaches and changes in vision.
  • Vision loss. Left untreated, a prolactinoma may grow large enough to compress your optic nerve. This can cause a loss of peripheral vision.
  • Low levels of other pituitary hormones. With larger prolactinomas, pressure on the normal pituitary gland can lead to lower levels of other hormones controlled by the pituitary, including thyroid hormones and cortisol (a stress-response hormone).

If you have prolactinoma and you want to become or are already pregnant, talk to your doctor. Adjustments in your treatment and monitoring may be necessary.