What is a Prolactinoma?

A prolactinoma is a prolactin-producing tumour of the pituitary gland. This is a benign tumour, and not a brain tumour or cancer.

Doctors use the words ‘tumour’, ‘adenoma’ or ‘growth’ which means a swelling on the pituitary gland. These tumours only grow very slowly and many do not seem to grow at all.

We do not know exactly what causes prolactinomas, but they are the most common type of hormone-producing pituitary tumour.

The action and stress of performing a blood test can mildly elevate the prolactin level and for this reason more than one level requires to be checked.

An appointment with an endocrinologist is usually sought by the GP, when there have been repeated raised levels of prolactin. Following referral to an endocrine department, the initial appointment will probably entail having your prolactin level re-checked.

Prolactinomas come in various sizes, but the vast majority are less than 10mm (3/8 inch) in diameter. These are called microprolactinomas. The rarer, large tumours greater than 10 mm in size are called macroprolactinomas. Prolactinomas can occur in men and women. The symptoms produced by a prolactinoma depend on the sex of the patient and the size of the tumour.

Typical Symptoms

  • discharge from breasts (Galactorrhoea) - females
  • irregular periods (Oligomenorrhoea) or loss of normal menstrual function (Amenorrhoea) - adult females
  • impotence - adult males
  • reduced fertility
  • decrease in sex drive
  • headaches
  • vision disturbance

Common causes of raised prolactin

  • Pregnancy
  • Nipple stimulation and suckling
  • Stress
  • Certain medications such as:
  • Anti sickness medications e.g. Metoclopramide, stemetil, Domperidone, also acid reducing medication like Omeprazole can raise your prolactin level.
  • Certain antidepressants and tranquillisers used to treat mental health illness can raise prolactin: examples include Amytriptyline and Fluoxetine (Prozac) and risperidone.
  • Some homeopathic and herbal medications.
  • Another possibility of raised prolactin is an underactive thyroid gland, which can be diagnosed by a simple blood test and which requires treatment with thyroid hormone tablets.

Once your doctor has excluded these causes, he or she will consider the possibility of a prolactinoma.

Make sure you tell your doctor about all your current prescribed and any non-prescription medication you are taking.