Pituitary Tumours

What are pituitary tumours?

Pituitary tumours are abnormal growths that form in the pituitary gland, which is a key part of the body’s endocrine system. These tumours can interfere with hormone production and cause various symptoms depending on their size and the hormones affected. Generally, the majority of pituitary tumours are benign (non-cancerous) and slow-growing. They constitute approximately 10 percent of all primary brain tumours.

What is a pituitary gland?

The pituitary gland is a small oval-shaped endocrine gland located at the base of the brain just behind the nose and below the optic nerve (the nerve which leads to the eyes). It is about the size of a pea and is very important because it secretes several chemical messages known as hormones.

Hormones produced by the pituitary gland help to regulate and control the secretion of hormones from other endocrine glands which are responsible for the body’s growth, metabolism and maturation.

What are the types of pituitary tumours?

Pituitary tumours are either functioning (secreting excess hormones) or non-functioning (not secreting hormones). Both categories may invade or press on structures around the pituitary fossa (e.g., the optic nerves).

Functioning (secreting) tumours

These produce excessive amounts of specific hormones, which can lead to noticeable hormonal imbalances and related symptoms. Depending on the hormone involved, patients may experience symptoms due to hormone excess. These tumours are often detected earlier due to the effects of hormone overproduction on the body.

• Prolactinomas: Secrete prolactin can lead to irregular menstrual periods, infertility, and milk production (galactorrhoea) in women, and reduced libido and erectile dysfunction in men. These are one of the few types of pituitary tumours that can be treated with medications.
• Somatotroph tumours: Secrete growth hormone (GH). This can cause acromegaly in adults (disproportionately enlarged hands, feet, facial features) or gigantism (excessive growth) in children.
• Corticotroph tumours: Secrete adrenocorticotropic hormone (ACTH). This stimulates the adrenal glands to produce cortisol, leading to Cushing’s disease (weight gain, high blood pressure, skin changes, suppressed immune system).
• Thyrotroph tumours: Secrete thyroid-stimulating hormone (TSH). This causes hyperthyroidism, resulting in symptoms such as weight loss, rapid heart rate, tremors and anxiety.
• Gonadotroph tumours: Secrete luteinizing hormone (LH) or follicle-stimulating hormone (FSH). These are rare and often do not cause noticeable hormone-related symptoms, but may result in infertility or menstrual irregularities.

Nonfunctioning (non-secreting) tumours

These tumours do not release active hormones. They may grow slowly and remain undetected until they become large enough to press on nearby structures. Symptoms are usually due to the mass effect of the tumour, such as headaches, visual disturbances or fatigue due to reduced hormone production from the surrounding normal pituitary gland tissue.

• Reduced vision: This is caused by longstanding direct pressure from the tumour on the optic nerves. This results in ischaemia of the optic nerves and manigests as progressive decline in visual acuity, colour vision and the field of vision. Pituitary tumours classically cause narrowed vision due to compression on the optic chiasm (intersection of the optic nerves), which is directly above the pituatary gland.
• Hypopituitarism: It results in amenorrhoea (no menstruation), cold intolerance, general weakness, decreased libido, etc. At its most severe state, it can be life-threatening due to low blood pressure and drowsiness (from low cortisol and/or thyroid hormone levels).
• Gigantism: It happens to the younger group of patients before bones mature if the tumour produces excessive amount of growth hormone.
• Acromegaly: It causes enlargement of lip, hand and feet, also lead to high blood pressure and diabetes if the tumour produces excessive amount of growth hormone.
• Moon face, weight gain, increase facial hair in women and mental health: Excessive Adreno-Corticotrophic hormone (ACTH) stimulates the adrenal gland to make and secrete glucocorticoids. Excessive amounts of glucocorticoid hormones causes build up of fats in the face, neck, trunk, weight gain, increased facial hair in women and mental health such as depression. Excessive amount of sugar (Diabetes Mellitus) and high blood pressure may occur.
• Irregularity of menstruation, loss of sexual function, infertility and general weakness: Due to excessive production of prolactin, there may be irregular menstruation, inappropriate milk production by the breast (galactorrhoea) and infertility in women; impotence and infertility in men.
• Headaches, nausea, drowsiness: If left unchecked, pituitary tumours can grow until they are very large, and cause obstruction to the cerebrospinal fluid flow in the brain, resulting in water accumulation and increased intracranial pressure (hydrocephalus).

When should you see a doctor?

You should see a doctor if you notice any unusual changes in your health that do not improve or have no clear explanation. This includes concerns related to hormonal imbalance, reproductive health or general well-being.

What are the potential complications of pituitary tumours?

Complications of pituitary tumours are long-term problems that may develop due to the tumour's growth, its impact on hormone production or as a result of treatment

• Delayed or incomplete recovery of vision: Even after treatment, vision may not fully return if the optic nerves have been compressed for too long.
• Hormonal dependency: Surgery or radiotherapy may damage healthy pituitary tissue, resulting in the need for lifelong hormone replacement therapy, including cortisol, thyroid and sex hormones.
• Recurrent tumour growth: Some tumours can regrow after surgery, requiring further intervention or long-term monitoring with imaging and blood tests.
• Secondary tumours from radiotherapy: Though rare, radiation treatment carries a small risk of inducing other tumours in the long term.
• Complications from hormone overexposure: Prolonged excess of hormones such as growth hormone or cortisol can lead to permanent changes, including joint deformities, metabolic disease or damage to the heart and blood vessels.
• Infertility and sexual dysfunction: Persistent hormonal disruption can impair fertility, libido and sexual function even after tumour removal.
• Emotional and psychological burden: Living with a chronic pituitary disorder can lead to anxiety, depression or reduced quality of life, especially if treatment is complex or prolonged.
• Pituitary crisis (apoplexy): Sudden bleeding into the tumour or loss of blood supply can cause collapse, severe headache and hormonal shock. It is a medical emergency that may result in permanent endocrine damage.

How are pituitary tumours prevented? 

There is no known way to prevent pituitary tumours, as most cases occur without a known cause. However, the following steps may support early detection and reduce the risk of complications:

• Attend regular health check-ups to monitor for hormonal imbalances or unexplained symptoms
• Seek medical advice promptly if you experience vision changes, persistent headaches or signs of hormone irregularities
• Manage known hereditary conditions, such as multiple endocrine neoplasia type 1 (MEN1), through genetic counselling and routine screening
• Maintain a healthy lifestyle to support overall endocrine health, including a balanced diet, regular exercise and adequate sleep
• Avoid unnecessary exposure to radiation, especially to the head or neck region
• Keep a record of family medical history and inform your healthcare provider of any relevant conditions

What causes pituitary tumours?

The cause of pituitary tumours, like that of other brain tumours, is unknown. It can occur in all age groups, but it is more common in middle and older age groups.

What are the risk factors for pituitary tumours?

Several factors may increase the likelihood of developing pituitary tumours, including:

• Hereditary conditions: Certain inherited disorders are associated with an increased risk of pituitary tumours. These include Multiple Endocrine Neoplasia type 1 (MEN1), Carney complex and familial isolated pituitary adenomas (FIPA). A family history of endocrine tumours may also raise suspicion.
• Long-term use of hormone-related medications: Prolonged use of certain drugs that affect hormone levels may influence pituitary activity.
• Immune system disorders: Some autoimmune or inflammatory conditions may alter hormone regulation and potentially affect pituitary health.
• Metabolic conditions: Chronic issues such as obesity or insulin resistance may impact hormone feedback systems and contribute to tumour development.

How are pituitary tumours diagnosed?

The diagnosis of pituitary tumours may involve the following:

• Clinical history and examination: A detailed medical history taking and physical examination helps identify signs and symptoms related to hormonal imbalance, neurological changes or visual disturbances. This provides important clues about the tumour’s presence and effects.
• Computed tomography (CT) scan / magnetic resonance imaging (MRI) studies: Imaging studies are essential for visualising the size, location and extent of the tumour. MRI is preferred due to its superior detail in soft tissue structures around the brain and pituitary gland. CT may be used when MRI is not suitable.
• Endocrine evaluation: Blood and urine tests are conducted to assess hormone levels and detect overproduction or deficiency caused by the tumour. This helps determine if the tumour is functioning (hormone-secreting) or non-functioning.
• Visual field and acuity examination: Since pituitary tumours can press on the optic chiasm, formal testing of peripheral vision is performed to identify any loss or defects. Changes in visual field and acuity may indicate the need for earlier treatment.

• Transsphenoidal surgery: This is the preferred method for most pituitary tumours. This minimally invasive technique involves accessing the tumour through the nasal passage using an endoscope or microscope. This approach avoids external scars and generally results in a shorter recovery period. It is best suited for tumours that are confined to the sellar region or have only limited extension beyond it. The procedure is associated with a lower risk of complications and is widely used in centres specialising in pituitary surgery.
• Craniotomy: This is an open surgical approach used for larger or more complex tumours that cannot be safely accessed through the transsphenoidal route. In this procedure, a portion of the skull is temporarily removed to allow direct access to the tumour from above. This approach may be necessary when the tumour has extended significantly into areas such as the brain or the cavernous sinuses. After the tumour has been removed, the bone flap is replaced and secured. Craniotomy carries a longer recovery time and a higher risk of complications, but it may offer the only viable route for complete or partial removal in select cases.

Drug therapy
Thyroxine and hydrocortisone tablets are some examples of common drugs to replace hormones deficiencies. Drug therapy may be a lifelong treatment and must be continued even in sickness.

Bromocriptine or cabergoline is given for prolactinomas, as suppressing prolactin production may cause shrinkage of the tumour.

Radiation treatment
Pituitary tumours in patients unfit for surgery or those that extend beyond the pituitary fossa require treatment by radiation. Radiation treatment is also an option for small pituitary tumours that do not compress the optic nerves.

Radiation is carried out using a Novalis Shaped-Beam machine that delivers narrow beams of strong radiation aimed precisely at the tumour from many different directions. Normal brain tissue therefore receives only a fraction of the total radiation dose received by the tumour.

Exact knowledge of the tumour location is necessary, and this is achieved by securing the head firmly but painlessly in a custom-made mask system and doing a CT scan of the head with the mask system in place. For treatment planning, an MRI scan of the head is also required.

Follow-up and monitoring for recurrence
It is very important to visit your doctor regularly for follow-up with laboratory tests of hormone levels and imaging studies (e.g., MRI). If recurrence is diagnosed, further treatment may be necessary. Large recurrences may require radiation therapy and/or drug therapy as well.

Are pituitary tumours cancerous?
Most pituitary tumours (>98%) are benign, meaning they are not cancerous (i.e. they do not spread to elsewhere in the brain or body). They usually grow slowly and do not spread to other parts of the body, but can still cause health problems if they affect hormone levels or press on nearby structures.

Can pituitary tumours cause vision problems?
Yes, if a pituitary tumour grows large enough, it can press on the optic chiasm, the intersection of the optic nerves. This pressure can lead to blurred vision or reduced peripheral vision, and may require earlier treatment.

Do all pituitary tumours require surgery?
Not all pituitary tumours need surgical removal. Treatment depends on its size, location and whether the tumour is producing hormones. Some tumours may be managed with medication, observation or radiotherapy.