Non-functioning pituitary adenoma: symptoms, tests, treatment and follow-up

The pituitary gland is a small gland at the base of the brain, just behind the eyes. Cancer Research UK explains that it makes and releases hormones into the bloodstream and that these hormones control many functions in the body. Tumours of the gland are called pituitary adenomas or pituitary neuroendocrine tumours (PitNETs), and they are divided into two groups depending on whether or not they make hormones.

A non-functioning adenoma is one that does not make hormones. The Pituitary Foundation describes it as by far the most common type, about half of all pituitary tumours. Because it does not release a hormone that produces a recognisable syndrome, it is often found late, either because of the effects of its size or because it shows up on a scan done for another reason.

Symptoms come from two mechanisms. The first is pressure from the tumour on nearby structures. Cancer Research UK says non-functioning tumours are usually larger than those that produce hormones and can cause headaches, and that they can press on the optic nerves, which connect the eyes to the brain, causing changes such as blurred or double vision. The Pituitary Foundation also lists visual field disturbance.

The second mechanism is pressure on the normal part of the pituitary gland. The Pituitary Foundation says this can stop the gland producing enough of one or more of its hormones, leading to hypopituitarism. The symptoms depend on which hormones are low, and a decrease in only one hormone would not cause all of them.

• Excessive tiredness and decreased energy.

• Muscle weakness, weight gain, increased sensitivity to cold, constipation and dry skin.

• Reduced body hair and a pale appearance.

• In women, irregular periods or loss of periods; in men, impotence. Reduced fertility and decreased sex drive can affect either.

• Low blood pressure with dizziness on standing.

• Headaches and vision disturbance.

• Very rarely, a loss of the hormone that controls water balance (arginine vasopressin deficiency).

Cancer Research UK says that a doctor examines you and checks your symptoms, then arranges tests to diagnose a pituitary tumour and plan treatment. The tests include blood tests and an MRI scan or CT scan. The blood tests look at pituitary hormone levels and those of the glands the pituitary controls, which shows whether any hormones have been lost and whether the tumour is secreting one after all, which would make it a functioning tumour.

Because the tumour sits close to the optic nerves, an eye and visual field check is often part of the work-up when symptoms suggest pressure on them. The scan shows the size of the tumour and its relationship to surrounding structures, which helps decide whether treatment is needed. Some small tumours are found by chance on a scan done for something unrelated, and for these the question is whether anything needs doing at all.

Cancer Research UK says the treatment depends on the type of tumour, how well you are and your symptoms. Pituitary tumours usually grow slowly over several years, so for a small tumour that is not causing symptoms, the doctor might monitor you with regular MRI scans, called active monitoring, and treat only if the tumour grows or starts to cause symptoms.

Surgery is considered for larger tumours. A neurosurgeon removes as much of the tumour as possible. Most people have surgery through the nose, called transsphenoidal surgery, using a thin tube with a camera and light (an endoscope). A craniotomy through the skull may be used if the tumour is large. Radiotherapy may be given after surgery to treat any tumour left behind, or if surgery is not suitable.

Hormone replacement is part of treatment for many people, because the tumour, surgery or radiotherapy can leave one or more hormones low. Whether replacement is needed, and for how long, depends on which hormones are low, and your endocrinology team will review this over time.

Even after successful treatment, follow-up is long term. Typical follow-up includes repeat blood tests for pituitary hormones, checks of vision and periodic MRI scans to look for regrowth, and the schedule is set by your endocrinology team and depends on the tumour, the treatment and whether the tumour was fully removed.

Living with hormone replacement means learning to take medicines such as steroid replacement reliably and knowing the sick-day rules that apply, which the Pituitary Foundation provides information about. The charity also runs support groups and telephone buddies, and it has information on living with a pituitary condition. Tiredness and low mood can persist for some time even when hormone levels are corrected, and it is worth raising them at follow-up.

A sudden, severe headache or a rapid change in vision, particularly in someone known to have a pituitary tumour, should be treated as urgent and assessed through NHS 111, 999 or A&E. If you take steroid replacement, the Pituitary Foundation publishes emergency information and steroid sick-day rules, and you should follow the guidance your endocrinology team has given you.

Less dramatic changes, such as gradual headaches, tiredness or changes in vision, should lead to a GP appointment so that hormone levels and, if needed, scans can be arranged.

On the NHS, pituitary tumours are usually looked after by an endocrinologist, with a specialist surgical team involved if an operation is needed and an eye team monitoring vision. Private endocrinology and imaging are also available and can sometimes shorten the wait for tests, but surgery for pituitary tumours is a specialist field and is best carried out by a team that does it regularly.