Pituitary adenoma

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

Some pituitary adenomas make hormones, but others do not. Pituitary adenomas that do not make hormones are called non-functioning or non-secreting tumours. Whereas those that do make hormones are called functioning or secreting tumours.

Our hormones regulate many important bodily functions and processes. Symptoms will depend on which hormone is affected.

There are a number types of Pituitary adenomas that make hormones:

• Prolactinomas – these tumours produce the hormone prolactin and can cause increased milk production and menstruation to decrease or stop, infertility and loss of sex drive.
• Somatotroph Adenomas – these tumours produce growth hormone and can Acromegaly in adults or gigantism in children characterised by unusual increases in height in young people and unusual growth of some body parts such as the hands and feet in adults.
• Corticotroph adenomas – produce the hormone adrenocorticotropic hormone (ACTH) which is linked to the production of another hormone called cortisol. Over production of cortisol is known as Cushing’s syndrome which can cause symptoms such as weight gain and a red, puffy, rounded face.
• Thyrotroph adenomas – these tumours produce thyroid-stimulating hormone (TSH), which can cause the thyroid to become overactive (hyperthyroidism) and which can cause symptoms such as weight loss, mood swings, heart palpitations and sensitivity to heat.

How the size of the tumour affects pituitary adenoma symptoms

The terms micro and macro are used to describe the size of a Pituitary Tumour.

Micro – is used for tumours that are below 10mm or 1cm in diameter

Macro – is used for tumours that are larger then 10mm or 1cm in diameter

Therefore a pituitary adenoma that produces prolactin and is over 10mm in size may be referred to as a macroprolactinoma.

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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