A pituitary tumour is a tumour that grows on the pituitary gland. This important gland plays a major role in controlling the balance of hormones in the body. In some cases, tumours lead to a reduction in hormone secretion, while in others they can cause an excessive production of certain hormones. Most pituitary tumours are benign (non-cancerous) and these are known as adenomas. They do not spread to other parts of the body. Large tumours are known as macroadenomas, while smaller tumours are called microadenomas.
Symptoms of a pituitary tumour
Symptoms that can arise as a result of a pituitary tumour include:
- nausea and sickness
- feeling weak and tired
- unexplained changes in weight
- loss of body hair
- disturbed vision (especially related to peripheral vision)
- erectile dysfunction and loss of libido
- changes in periods in women
- increased urination
In some cases, tumours also produce hormones and this contributes to over-production of certain hormones. This can cause additional symptoms. The type of tumour often affects the nature of symptoms as follows:
ACTH (adrenocorticotropic hormone-secreting) tumours create the hormone adrenocorticotropin, which results in the adrenal glands producing more cortisol. One effect of excessive levels of cortisol is Cushing’s syndrome. Symptoms of this syndrome may include:
- high blood pressure
- fat collection in the upper back and around the waist
- weight gain in the face
- reduced muscle strength
- bruising easily
- a humped back
- stretch marks in the skin
- increased susceptibility to anxiety and stress
- thinner skin
Prolactin-secreting tumours: excessive production of prolactin can affect both male and female sex hormones. In women, symptoms include irregular periods, less frequent periods and lactation from the breasts, while men may experience reduced libido, erectile dysfunction and even infertility.
Thyroid-stimulating hormone-secreting tumours: over-production of thyroid hormone contributes to hyperthyroidism and symptoms include:
- rapid and unexplained weight loss
- irregular heartbeat and palpitations
- more frequent bowel movements
- struggling to control body temperature
- feeling anxious or irritable
What causes pituitary tumours?
It is not known what causes pituitary tumours. In some cases, there is evidence to suggest that tumours run in families, but this is not the case in the majority of individuals. Risk factors that have been identified include:
- age: most cases occur in older adults
- family history of MEN I (multiple endocrine neoplasia type I)
When should I see my doctor?
If you experience symptoms like those listed above, arrange an appointment with your GP. Your doctor will talk through your symptoms with you and they may also carry out a quick physical examination. If they suspect you have a pituitary tumour, further tests will be carried out. If your hormone levels are imbalanced, it is usually possible to treat this effectively and treatment usually alleviates the associated symptoms.
Before you go to your GP, it’s a good idea to note down any symptoms you have been experiencing and any medications you are taking or have taken in the past 6-12 months. If you have any questions, don’t be afraid to ask your doctor.
What are the effects of pituitary tumours?
In most cases, there is no danger of a tumour growing or spreading outside of the gland. However, tumours can cause complications, including:
- Disturbed vision and loss of peripheral vision (this is due to the tumour applying pressure to the optic nerve)
- Loss of hormone regulation: a tumour may affect your ability to regulate and supply certain hormones
- Diabetes insipidus: this form of diabetes causes you to experience frequent thirst and an urge to urinate frequently. It occurs as a result of reduced production of vasopressin by the pituitary gland. This chemical is related to kidney function and is responsible for regulating the concentration of the urine
- Bleeding: in very rare cases, a tumour can bleed. This is known as pituitary apoplexy and it requires urgent medical treatment
How is a pituitary tumour diagnosed?
If your GP suspects that you have a tumour, they will suggest further tests, including blood tests, vision and sight tests and imaging scans, which may include a CT scan, an MRI scan or both. The results of the tests will be used to confirm or rule out a diagnosis. If you are diagnosed with a tumour, you will probably be referred for specialist treatment and your care team will explain exactly what the diagnosis means, how it affects you and what kinds of treatments are available to you.
Treatment for pituitary tumours
The treatment options usually depend on the size and exact location of the tumour and also the type of tumour. Your age, general health and medical history will also be taken into consideration when exploring possible treatment options. Treatment is usually required, as the tumour places pressure on the gland and the brain. Early treatment is usually the best option.
Surgery is often recommended to treat a tumour and will usually involve removing the mass. There are two main types of surgery used for this type of tumour: the endoscopic transnasal transsphenoidal approach and transcranial treatment. When using the endoscopic method, the surgeon can usually access the tumour through the nose. The transcranial method involves removing the tumour by making an incision in the scalp in the upper part of the skull. Endoscopic treatment is usually recommended for smaller tumours, while transcranial treatment may be better for larger tumours.
Radiotherapy, also known as radiation therapy, is a technique used to destroy tumours. It can be used independently or in addition to surgery. There are two main types of radiotherapy, including external beam radiation and Gamma Knife stereotactic radiosurgery.
External beam radiation exposes you to small doses over a period of time and treatment is delivered in a sequence of sessions. Although treatment may be effective, it can take time and there is a risk of damage to the surrounding healthy tissue.
Gamma Knife stereotactic radiosurgery concentrates on the tumour only and exposes you to a lower dose of radiation. Imaging technology is used to deliver radiation beams that are the same shape as the tumour. This technique helps to protect healthy tissue around the tumour, but it can take a long time to produce positive results.
Medication can be used to reduce the size of tumours and control hormone production, also helping to alleviate symptoms.
Growth-hormone secreting tumours: medicines used to treat this type of tumour include somatostatin analogs. These drugs help to reduce the size of the tumour and decrease the production of growth hormone. Possible side-effects include feeling dizzy and sick, vomiting, changes in bowel habits, tiredness and drowsiness.
Prolactin-secreting tumours: drugs including cabergoline and bromocriptine are used to treat this type of tumour. These medicines decrease the size of tumours and also reduce prolactin secretion. Often, medication is effective and surgery is not required. Possible side-effects include nausea and sickness, feeling tired and drowsy, dizziness, changes in bowel habits and an increased risk of anxiety and depression.
Sometimes, if the tumour is not causing any problems or symptoms, doctors may advise a policy of watchful waiting. This involves refraining from giving treatment and keeping an eye on the tumour to see if it develops or starts causing problems.