Frequently Asked Questions about Pituitary Tumours

The pituitary, also called the hypophysis, is a gland situated in the sella turcica, and is considered the principle gland of the endocrine system. It has a coordinating function that collects the messages from the brain and uses this information to produce hormones that stimulate and regulate other endocrine glands (thyroids, adrenals, gonads – testicles and ovaries-) and segregates hormones that act directly on essential biological functions such as growth, body water balance, or partum and lactation.

The pituitary is situated at the base of the skull, behind the bridge of the nose, in a bone depression that is called the sella turcica. It weighs approximately half a gramme and measures about 10 mm wide x 6 mm from the anteroposterior axis x 5 mm in height. It is joined to the hypothalamus via the pituitary stalk, which is part of the brain. The optic nerves (involved in the sight) pass immediately above the pituitary, and their nerve fibres cross (optic chiasma). The sphenoid sinus is situated at the lower edge, which is the usual entry route by the surgeon in pituitary surgery. The cavernous sinuses are situated on either side, where the vascular and nerve structures are found.

The pituitary is formed by two lobes: the anterior lobe, or adenohypophysis, and the posterior lobe, or neurohypophysis.

The anterior lobe produces 6 hormones: growth hormone (GH); prolactin; thyrotropin (TSH); corticotropin (ACTH); the gonadotropins (luteinising hormone –LH- and follicle stimulating hormone –FSH-).

The posterior pituitary (neurohypophysis) releases 2 hormones that are produced in the hypothalamus and that, conducted by the pituitary stalk, are stored in the posterior pituitary until they are released. These are oxytocin and antidiuretic hormone or vasopressin.

A pituitary tumour is a lesion located in the pituitary gland. The majority of pituitary tumours are pituitary adenomas (estimated at 95%) that originate from the cells of the pituitary itself. They are practically always benign and slow growing, with only a small percentage extending into neighbouring structures. Craniopharyngiomas and meningiomas are also pituitary tumours. Other pituitary lesions, which are not of tumour tissue, are the vascular lesions (haemorrhages, aneurysms, etc.), inflammatory (hypophysitis), infectious (pituitary abscess, tuberculosis…), or cysts. Pituitary metastases (metastasis in pituitary of tumours of other origins) are rare.

The pituitary adenomas are the most common intracranial tumours (estimated as 10% of all central nervous system tumours). They often go clinically unnoticed and are detected while performing an imaging test for another reason. This is what is known as a pituitary incidentaloma.

They are more common in women, and between the third and sixth decade of life.

They are sporadic in 95% of cases and the cause is unknown. The remaining 5% have a genetic cause, and are produced due to complex familial syndromes, such as multiple endocrine neoplasia types 1 and 4, Carney complex, or familial isolated pituitary adenomas (FIPA). 

Nothing can be done to prevent a pituitary tumour; however, it is important that in the case of a significant headache that is not usual, or the loss of vision, to go to the doctor for an appropriate study and to rule out a pituitary tumour in the event that the clinical symptoms suggest this.

Pituitary tumours are often asymptomatic, and their finding is casual while performing a brain imaging test for another reason. The symptoms that appear are associated with the size of the lesion, the relationship with the neighbouring structures or the production of hormones.

The symptoms can be divided into three groups: symptoms associated with the compression of neighbouring structures (mass effect) can cause headache, loss of vision, or double vision. There could also be symptoms associated with hormone deficiencies, giving rise to tiredness, weight increase, decreased libido, changes in menstrual rhythm, mood changes… Similarly, there may be symptoms associated with the excessive production of hormones, as in the case of functioning adenomas. The symptoms are different depending on the hormone that is produced in excess.

Pituitary tumours are often diagnosed casually while performing a brain imaging test. The ideal imaging test to evaluate a pituitary tumour is a nuclear magnetic resonance scan, which allows us to evaluate the type of pituitary tumour, the size, and the relationship with the neighbouring structures.

When the presence of a pituitary tumour is confirmed, blood tests are performed to determine the pituitary production of hormones, as well as the peripheral ones, and to assess if there is any hormone deficiency or over-production.

Five percent (5%) have a genetic cause, and are produced due to complex familial syndromes, such as multiple endocrine neoplasia types 1 and 4, Carney complex, or familial isolated pituitary adenomas (FIPA). When a familial type is suspected, whether in the family or other cases, due to the type of tumour or due to the presence of other tumours in other organs, the first thing is to analyse the patient by means of a genetic study with blood tests. Changes will be looked for in the DNA compared to the normal pattern, called mutations. If this study is positive, the mutation found will be analysed in first degree relatives (parents, siblings and children). If the mutation is found in relatives, it will be studied using the tests required to find out if they have the disease.

The first line treatment in pituitary tumours is usually surgery. It is indicated in cases of macro-adenoma (tumour more than 1 cm), when it compresses the optical pathways, or when the hormone study demonstrates an excessive production (as in the cases of GH and ACTH production in acromegaly and Cushing’s disease, respectively). However, the prolactinoma, a prolactin secreting tumour and the most common of the functioning pituitary tumours, is a secreting tumour that is usually treated medically, with no need for surgical intervention except in special cases.

Pituitary surgery consists in extirpating the tumour, leaving the healthy tissue of the gland intact. Pituitary surgery has markedly improved in the last few years, mainly due to the approach by the trans-sphenoidal route, which consists of extirpating the tumour by making an incision at the level of the nose, entering through the sphenoidal sinus (a cavity located behind the nose). Classically, it was performed through a craniotomy (transcranial route), in which the skull was opened to enter and remove the tumour. Currently, this transcranial technique is only used in exceptional cases where the trans-sphenoidal approach is not possible. In order to visualise the surgical area by the trans-sphenoidal route, a surgical microscope or a fibre optics endoscope is employed that allows using a minimally invasive approach to the pituitary.

The benefits of the trans-sphenoidal technique compared with the classic technique have a direct impact on the patient, with a significant reduction in local complications, a decrease in surgical time, an increase in patient comfort (absence of post-surgical nasal plugging, and a decrease in post-surgical pain), as well as a reduction in the mean hospital stay, which may be only 24-48 hours.

In general, after the surgery, intensive care is not needed. There is often headache and nasal congestion, a slight decrease in taste and smell, which will gradually disappear in the following days. Although you may feel tired, it usually improves in a few days, which means that you can start working again in a few weeks. It is important to get in touch with the doctor if there is fever, abundant clear fluid comes out of the nose or the throat, a headache that does not ease with the prescribed analgesics, a loss of vision, or a significant increase in the amount of urine or thirst.

Among the complications directly related to the surgery are haemorrhages, leaks by the nose of internal fluid of the brain, or infections, but they are very uncommon. The risk of a pituitary function deficiency (partial or complete hypopituitarism) depends on the size of the tumour and other characteristics.

The majority of pituitary tumours are benign and slow growing, and for this reason the prognosis is good and they are usually cured with medical or surgical treatment. However, some tumours can damage neighbouring structures and have a more aggressive behaviour, requiring multiple surgeries and more complex treatments, associated with radiotherapy and/or medical treatment.

Secretory tumours and non-secretory tumours can reappear after apparently being cured and, for this reason it is very important to be followed-up for life, by means of blood tests, magnetic resonance scans and/or eye tests. The frequency of the reviews and the tests will be set by the endocrinologist depending on the type of tumour and the treatments that may have been received.

In some tumours with small remains, that do not affect the sight, and are non-secretors, a close follow-up can be established using magnetic resonance scans, laboratory tests to evaluate hormone function as well as a study of the visual field. Some tumours may require multiple surgeries and more complex treatments, such as radiotherapy and/or medical treatment.

Radiotherapy is a type of treatment that uses high-energy particles or waves to eliminate tumour cells in order to prevent them growing and dividing, and can be used in both benign and malignant tumours. The radiation damages the tumour cells, which will stop them growing and dividing.

In the case of pituitary tumours, it is used when the tumour persists, grows, or re-appears after surgery, or when surgery cannot be performed due to a contraindication, or a low probability of success.

The medical treatment consists, on the one hand, of the treatment of the hormone deficiencies that may appear due to the presence of the tumour, or once it has been extirpated and, on the other hand, of the medical treatment that some tumours need in order to control excessive hormone secretion and their growth. 

In general, individuals with pituitary tumours, whether or not they are surgically treated, usually have a good quality of life, with no special limitations from the point of view of diet, exercise or sexuality, except in very rare cases with significant visual involvement or in certain secreting tumours.

Pregnancy may or may not be advised depending on the type of tumour.

Secretory tumours and non-secretory tumours can reappear after apparently being cured and, for this reason it is very important to be followed-up for life, by means of blood tests, magnetic resonance scans and/or eye tests. The frequency of the reviews and the tests will be set by the endocrinologist depending on the type of tumour and the treatments that may have been received.