Overview

Prolactinomas are prolactin-secreting adenomas, which cause hyperprolactinaemia. In women, the main symptoms of hyperprolactinaemia are menstrual disturbance, infertility and galactorrhoea; men can experience erectile dysfunction and diminished libido. In children, hyperprolactinaemia can cause pubertal delay.

Most prolactinomas are less than 10 mm in diameter (microprolactinomas). Prolactinomas that are 10 mm or more in diameter (macroprolactinomas) can cause pressure effects, such as headache and visual impairment, in addition to hyperprolactinaemia. Males tend to have larger and more aggressive prolactinomas than females.

A pregnancy test is mandatory in women of reproductive age with amenorrhoea and hyperprolactinaemia. Prolactinomas (and other pituitary adenomas) can occasionally expand during pregnancy, and the risks associated with expansion must be carefully assessed before attempting to conceive. See Prolactinomas during pregnancy.

Prolactinomas are usually treated with dopamine agonist therapy.

Serum prolactin concentration can be elevated by mechanisms other than prolactinomas (see Causes of hyperprolactinaemia).
Figure 1. Causes of hyperprolactinaemia.

[NB1]

Hyperprolactinaemia can be caused by:

  • a prolactinoma
  • disruption of the pituitary stalk (trauma, surgery, tumour)
  • pregnancy
  • a hypothalamic disorder, including:
    • tumour (craniopharyngioma, glioma)
    • infiltration (sarcoidosis)
    • radiotherapy
  • certain drugs, including:
    • antipsychotics [NB2]
    • methyldopa
    • metoclopramide
    • domperidone
    • opioids
    • selective serotonin reuptake inhibitors (SSRIs)
    • tricyclic antidepressants
    • cannabis
    • oral contraceptive pills
  • a systemic disorder, including:
    • hypothyroidism
    • kidney disease
    • liver failure
    • epileptic seizures
  • a neurogenic cause, including:
    • breast stimulation and lactation
    • chest wall trauma or lesion
    • stress
  • pseudohyperprolactinaemia.
Note:

NB1: Hyperprolactinaemia is occasionally idiopathic, with no pituitary adenoma or other cause apparent.

NB2: For antipsychotic-induced hyperprolactinaemia, aripiprazole can be useful; see Hyperprolactinaemia caused by antipsychotics for more information.