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Pituitary adenoma

Pituitary adenomas (also called pituitary neuroendocrine tumour or PitNET) aren’t brain tumours, strictly speaking. But they have many similar symptoms and side effects. These tumours form in the pituitary gland and are usually slow-growing. It’s estimated that up to one in five people will develop them at some point.

Short summary

A pituitary adenoma is a tumour that develops in the pituitary gland, which is not technically part of the brain. However, the pituitary gland does affect brain function, which is why these tumours can have similar symptoms to brain tumours.

Symptoms can relate either to hormone production or pressure in the brain. They can include loss of periods in women, lowering of testosterone in men, unexpected weight gain, bruising of the skin and muscle weakness.

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What is a pituitary adenoma?

A pituitary adenoma (also called pituitary neuroendocrine tumour or PitNET for short) is a tumour that develops from the tissue of the pituitary gland (or hypophysis).

The pituitary gland is found at the base of the brain and belongs to the endocrine system (which controls many of the body functions through the hormones).

Pituitary adenomas are identified incidentally in around 17% of the population.

The commonness of pituitary adenoma increases with age and they occur equally in men and women, although some studies show that certain subtypes occur more often in women.

What are the pituitary adenoma symptoms?

Pituitary adenomas can cause symptoms either by affecting hormone production or by the effect of a large mass pressing on surrounding brain tissue. Below we’ll discuss the pituitary adenoma symptoms related to both of these.

How hormone production affects pituitary adenoma symptoms

Our hormones regulate many important bodily functions and processes. Symptoms will depend on which hormone is affected. Possible symptoms of hormone-producing adenomas include:

From over-production

  • Loss of menstrual periods in women
  • Lowering of testosterone in men, leading to loss of sexual appetite
  • Acromegaly in adults or gigantism in children, which causes extreme growth spurts
  • Unexpected weight gain
  • Easy bruising of the skin and muscle weakness

From under-production

  • Loss of sex drive and infertility
  • Hypothyroidism, causing appetite loss, weight gain, fatigue and decreased mental function
  • Adrenal insufficiency, which can cause fatigue, low blood pressure, electrolyte abnormalities
  • Growth hormone insufficiency which can cause delayed puberty and in adults tiredness and loss of muscle mass
  • disorder of the endocrine system in which the thyroid gland does not produce enough thyroid hormone

How the size of the tumour affects pituitary adenoma symptoms

The growth of this type of tumour can put pressure on surrounding tissue, especially the optic nerve, causing vision problems or loss of peripheral (side) vision and other related problems. An increase in the pressure surrounding the optic nerve can be identified during an eye test.

Pituitary adenomas can also cause many of the same symptoms as other brain tumours.

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How is a pituitary adenoma treated?

Pituitary adenoma treatment depends on the symptoms and the tumour itself.

If the only symptom relates to the levels of hormones produced, this can be managed by medication and is usually arranged by a neuro-endocrinologist.

If the size or growth of the tumour is of concern, then neurosurgery may be required. The surgery can be non-invasive by using instruments inserted through the nose.

Alternatively, stereotactic radiosurgery can be used to very accurately target the tumour with radiation. This causes much less damage to the healthy brain cells around the tumour than regular radiotherapy.

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What causes pituitary adenomas?

The causes of pituitary adenomas remains largely unknown and more research is still needed. A small number of cases are believed to be hereditary.

It has not been proven that exposure or lifestyle are risk factors for pituitary adenomas.  

It’s important to know that there is nothing you could have done, or avoided doing, that would have caused you or somebody you know to develop a brain tumour.

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Pituitary adenoma life expectancy

For most people, treatment can control or remove the tumour giving you a normal lifespan. But you may have to deal with its consequences, such as vision or hormonal issues.

It’s also hard not to worry about the tumour growing or coming back. It can help to talk to others in a similar situation about how they have learned to live with this uncertainty.

Our online brain tumour support groups are a great way to connect with other people who’re affected by a brain tumour or you could find a local support group.

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If you have further questions, need to clarify any of the information on this page, or want to find out more about research and clinical trials, please contact our team:
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