There are numerous symptoms of a prolactinoma. The symptoms depending on the persons sex and the size of the tumour.
Symptoms in Women and AFAB
Most women with prolactinomas are likely to have microprolactinomas. Your first symptoms may relate to loss of periods (amenorrhoea) as excessive prolactin interferes with the pituitary’s production of the hormones FSH and LH which control the menstrual cycle.
You may have reduced interest in sex (low libido) and experience vaginal dryness and discomfort during intercourse.
You may also be infertile because of impaired egg release by the ovaries – there is usually effective treatment for this problem.
You may also develop excess breast milk production (called galactorrhoea), which may leak spontaneously. This is due simply to the biological action of prolactin and is not a sign of breast disease, particularly breast cancer. Women with prolactinomas do not have any increased risk of breast cancer. If galactorrhoea is a symptom: it is important to note that self-examination and expressing of milk acts as stimulation and therefore reinforces the raised prolactin level, making galactorrhoea persist! Although it is tempting to look to see if it is still present, you should resist the temptation.
Symptoms in Men and AMAB
Men with prolactinomas usually have tumours larger than 10mm in diameter (macroprolactinomas). Excessive prolactin reduces production of FSH and LH by the pituitary gland. This in turn lowers testosterone levels and may result in a reduced interest in sex (low libido) and in impotence.
Men may also have infertility due to a low sperm count. Milk production by the male breast can occur but is very uncommon even when prolactin levels are very high.
Once diagnosed and treatment with medication has been established and the abnormal level of prolactin starts to decrease, the abnormally low testosterone level should in turn start to recover and rise again. This does not happen in all cases and in that instance the men will go on to have hormone replacement therapy in the form of testosterone.
Symptoms of large tumours
If you have a large tumour, you may have pressure symptoms such as headache or visual problems. This is because the nerves to your eyes pass over the top of the pituitary gland. In a minority of patients, an increase in pituitary size may cause pressure on these nerves and produce visual disturbance.