A pituitary tumour is an abnormal growth in the pituitary gland, the part of the brain that regulates the body’s balance of hormones.
Causes
Most pituitary tumour are noncancerous (benign). Up to 20% of people have pituitary tumours. However, many of these tumours do not cause symptoms and are never diagnosed during the person’s lifetime.
The pituitary gland is a pea-sized endocrine gland located at the base of the brain. The pituitary helps control the release of hormones from other endocrine glands, such as the thyroid and adrenal glands. The pituitary also releases hormones that directly affect body tissues, such as bones and the breast milk glands.
These hormones include:
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- Adrenocorticotropic hormone (ACTH)
- Growth hormone (GH)
- Prolactin
- Thyroid-stimulating hormone (TSH)
As the tumour grows, hormone-releasing cells of the pituitary may be damaged, causing hypopituitarism.
The causes of pituitary tumours are unknown.
Other types of tumours that can be found in the same part of the head as a pituitary tumour:
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- Craniopharyngiomas
- Cysts
- Germinomas
- Tumours that have spread from cancer to another part of the body (metastatic tumours)
Symptoms
Most pituitary tumours produce too much of one or more hormones. As a result, symptoms of one or more of the following conditions can occur:
- Hyperthyroidism
- Cushing syndrome
- Gigantism or acromegaly
- Nipple discharge
Symptoms caused by pressure from a large pituitary tumour may include:
- Headache
- Lethargy
- Nasal drainage
- Nausea and vomiting
- Problems with sense of smell
- Visual changes
- Double vision
- Drooping eyelids
- Visual field loss
Rarely, these symptoms may occur suddenly and can be severe.
Exams and Tests
Your health care provider will perform a physical examination. The provider will note any problems with double vision and visual field, such as a loss of peripheral vision or the ability to see in certain areas.
Endocrine function tests include:
Cortisol levels:
- Dexamethasone suppression test
- Urine cortisol test
- Follicle-stimulating hormone (FSH) levels
- Insulin growth factor-1 (IGF-1) levels
- Luteinizing hormone (LH) levels
- Serum prolactin levels
- Testosterone/estradiol levels
Thyroid hormone levels:
- Free T4 test
- TSH test
Tests that help confirm the diagnosis include the following:
- Formal visual field testing
- MRI of head
Treatment
Pituitary tumours are usually not cancerous and therefore won’t spread to other areas of the body. However, as they grow they may place pressure on important nerves and blood vessels.
Surgery to remove the tumour is often necessary, especially if the tumour is pressing on the optic nerves, which could cause blindness.
Most of the time, pituitary tumours can be removed through the nose and sinuses. However, some tumours cannot be removed this way and will need to be removed through the skull (transcranial).
Radiation therapy may be used to shrink the tumour, either in combination with surgery or for people who cannot have surgery.
Sometimes medication may be used.
Outlook (Prognosis)
If the tumour can be surgically removed, the outlook is fair to good, depending upon whether the entire tumour is removed.
Possible Complications
The most serious complication is blindness. This can occur if the optic nerve is seriously damaged.
The tumour or its removal may cause permanent hormone imbalances. The affected hormones may need to be replaced.
