Pituitary tumor

The endocrine system is made up of glands that secrete chemicals called hormones into the bloodstream. The master gland is the pituitary, a pea-sized structure located at the base of the brain just behind the nose. The pituitary oversees the other glands of the endocrine system and controls hormone levels.

It can bring about a change in hormone production somewhere else in the system by releasing its own ‘stimulating’ hormones. The pituitary gland is also connected to the nervous system by a part of the brain called the hypothalamus. A pituitary tumor (also called an adenoma) is a mass of cells that grow on the gland.

Some tumors release hormones, although most do not. Generally, pituitary tumors are benign (not cancerous) and slow growing, and pituitary cancers are rare. Benign tumors don’t spread to other parts of the body, so there is no chance of secondary tumors developing.

Treatment may include surgery, radiation therapy and medication#

Symptoms of a pituitary tumor may have different causes#

If the tumor is releasing a hormone, high levels of that hormone may be present in the bloodstream. If the normal pituitary gland function has been affected, there may be lower levels of one or more of the pituitary hormones.

There could also be symptoms caused by a growth or ‘mass effect’, resulting in pressure of the tumor on surrounding structures. Symptoms may include: visual disturbances, such as loss of peripheral vision (giving you ‘tunnel vision’) or (rarely) double vision fatigue. The pituitary gland regulates many important bodily processes by releasing hormones into the bloodstream.

Some of the key hormones include:

• Adrenocorticotropic hormone (ACTH) – stimulates the adrenal glands to produce the hormone cortisol
• which is essential for life
• helps to regulate blood pressure
• blood sugar levels. Antidiuretic hormone (ADH) – helps the kidneys to maintain the correct amount of water in the body

Follicle stimulating hormone (FSH) and luteinizing hormone (LH) – regulate the menstrual cycle in women, sperm production in men and sex hormone levels in both sexes.

Growth hormone – influences a person’s height, contributes to bone and muscle building and influences the control of body fat. Oxytocin – is involved in childbirth and breastfeeding.

This hormone is also thought to help relieve the physical effects of stress#

Prolactin – prompts milk production after childbirth. Thyroid stimulating hormone (TSH) – stimulates the thyroid gland to produce the hormone thyroxine, which regulates energy expenditure. Although the effects of pituitary tumors are understood, like many tumors, the causes remain largely unknown.

A small percentage may arise because of an altered gene.

The different types of pituitary tumor include: growth hormone-producing tumor#

This is the most common pituitary tumor and doesn’t release any hormones.

Symptoms are caused by a deficiency in the normal pituitary hormones (because the tumor restricts the function of the normal gland), or by pressure on surrounding structures near the pituitary. Some of the symptoms of a non-functioning pituitary tumor include:

• loss of libido. This type of tumor secretes adrenocorticotropic hormone (ACTH)
• which causes the adrenal glands (situated above the kidneys) to produce greater than normal amounts of cortisol

This causes a disorder known as Cushing’s disease#

Too much circulating cortisol may also occur due to non-pituitary influences, including adrenal gland tumors or other tumors outside the pituitary that make too much ACTH. These result in a clinical syndrome called Cushing’s syndrome. The symptoms include:

• build-up of fat on the face (producing a ‘moon face’ appearance) plus a build-up of fat on the abdomen
• upper back purple stretch marks

This type of tumor releases prolactin, the hormone that naturally increases during pregnancy and after childbirth to stimulate milk production. A woman with a prolactin-producing tumor (prolactinoma) may have irregular or absent menstrual periods and her breasts may make milk, even if she isn’t pregnant.

The effects of this type of tumor in men include loss of libido and erectile dysfunction.

This type of tumor releases growth hormone#

Too much growth hormone forces certain body structures such as the face, hands and feet to enlarge and thicken considerably. This condition is called acromegaly, or gigantism if it occurs before growth stops during the adolescent years. The cardiovascular changes caused by the high levels of growth hormone can be fatal if untreated.

This condition also increases the risk of bowel polyps and cancer. A pituitary tumor is diagnosed using a number of tests including: computed tomography (CT) scans. Treatment depends on the type and size of the tumor, and the person’s age and general health.

Generally, the treatment options include:

• Surgery – the pituitary gland is accessed via the nasal cavity
• no visible cuts are made. The tumor is removed using an endoscope or microscope. In rare cases
• the tumor may have to be removed through the front of the skull (craniotomy)

Surgery is the first-line treatment for all tumors except prolactinomas. Radiation therapy – targets and destroys the tumor cells. Radiosurgery is focused radiotherapy that has improved the accuracy and minimized the risks of treating pituitary tumors.

Radiosurgery is used in conjunction with surgery and medications to control the growth of tumors or to stop the activity of hormone-releasing tumors. Medication – to shrink the tumor and stop it from producing hormones.

Medication is the first line of treatment for prolactinoma#

Hormone replacement therapy may also be required in cases of pituitary hypofunction or post-operatively. Your doctor may refer you to a medical specialist such as: an endocrinologist – one who is experienced in the management of pituitary tumors.

They will decide on the appropriate investigations#

If surgery is necessary, they will refer you to a neurosurgeon with a special interest in pituitary tumor surgery a neurosurgeon– the skill of the neurosurgeon (particularly one who treats pituitary tumors regularly) is the most important variable in a cure, especially for functioning tumors (ones that are making excessive amounts of a hormone).

Symptoms of pituitary tumors loss of libido (sex drive) or erectile dysfunction (inability to have an erection) in men menstrual period irregularities in women changes to appearance cognitive difficulties, including problems with thinking persistent headaches nausea and vomiting light-headedness on standing up Roles of the pituitary gland Types of pituitary tumors non-functioning pituitary tumor ACTH-producing tumor prolactin-producing tumor (prolactinoma) Non-functioning pituitary tumor general fatigue and feeling unwell persistent headaches menstrual cycle irregularities loss of peripheral vision ACTH-producing tumor wasting of the arm and leg muscles high blood sugar levels a reddened, flushed face high blood pressure (hypertension) osteoporosis (thinning of the bones) thinning of the skin and easy bruising Prolactin-producing tumor Growth hormone-producing tumor Diagnosis of pituitary tumors medical history physical examination blood tests magnetic resonance imaging (MRI) scans Treatment for pituitary tumors Specialist advice about pituitary tumors

Where to get help#

Key Points#

• Treatment may include surgery, radiation therapy and medication
• Symptoms of a pituitary tumor may have different causes
• pituitary gland regulates many important bodily processes by releasing hormones into the bloodstream
• Antidiuretic hormone (ADH) – helps the kidneys to maintain the correct amount of water in the body
• Although the effects of pituitary tumors are understood, like many tumors, the causes remain largely unknown