Pituitary tumor

A growth in the small gland under the brain that controls hormones. Why sight and hormones are the two things to watch. What the names on your report mean. And the two emergencies this page carries rules for.

The short version

A pituitary tumor is a growth in a small gland that sits under your brain. Almost all of them are not cancer.

The gland runs your hormones, and the nerves for sight pass just above it. So the two things a team watches are your hormones and your sight.

Treatment is not always surgery. Some are watched. Some are treated with pills alone. When there is an operation, it is usually done through the nose.

Two things on this page are emergencies: a sudden, severe headache, and being ill if you take steroid replacement. Both are further down, and both are worth knowing before you need them.

What is a pituitary tumor?

It is a growth in the gland that tells your other glands what to do.

The pituitary is about the size of a pea. It sits at the base of the brain, behind your nose. It makes hormones that travel round the body, and many of them tell other glands to get to work. That is why it gets called the master gland.

A tumor here is a growth in that gland.

These are not brain tumors, and that is worth saying plainly. The Endocrine Society puts it that way: they are not brain tumors, and they are almost always not cancer. The gland sits under the brain rather than inside it, and the name for that is extra-axialextra-axial: Growing outside the brain itself, not inside it. A meningioma is one. It starts in the layers around the brain and presses inward. See the glossary.

That matters, and it does not settle everything. A growth outside the brain can still press on the nerves for sight. It can still stop a gland working. What it tells you is where the trouble comes from, not how much trouble you have.

You are reading this on a site about brain tumors, and your team may well have used those words. That is not a mistake either. This tumor sits in the same small space, gets found on the same scans, and is treated by some of the same people.

Is it cancer? What does its grade mean?

Almost always, no. Cancer of the pituitary is extremely rare.

Most pituitary tumors are what doctors call benign. But that word does more work than it can carry, so here is what it does and does not mean.

It means the growth is not spreading round your body. It does not mean harmless. A small growth in this spot can take part of your sight, because of what is sitting right above it. It can stop a gland working, and that can be serious. Not cancer and not a problem are two different sentences.

The grade 1 to 4 you may have read about for other brain tumors is not used for this one. Your report describes what the tumor is made of and which hormone, if any, it makes. Those are the things that change the plan. If a number does turn up beside a word you do not know, ask what it measures.

The useful questions are what it is pressing on, and whether it is making a hormone. Both are further down this page.

Where does it grow, and why does it cause these symptoms?

Almost everything on this page follows from what is next door.

The gland sits in a small hollow of bone. Directly above it, the nerves that carry sight from each eye cross over. To each side run the nerves that move your eyes.

So a growth here has three ways of causing trouble.

It can press upward on the nerves for sight. They cross right above the gland, which is why the sight that goes first is usually at the outer edges. You may not notice it early. People often find it by bumping into door frames, or in a sight test.

It can press sideways on the nerves that move your eyes. Then things look double, or one eyelid droops, or an eye does not move the way the other one does.

It can change your hormones, in either direction. Some of these tumors make too much of one hormone. Others get big enough to stop the normal gland working, so you end up with too little. Both happen, and they feel completely different.

That three-way split is why two people with the same diagnosis can describe nothing alike.

The place rather than the name. Where your tumor is, and what that changes works from the spot on the scan. The same page has a section on why a scan result takes time to turn into a plan.

What symptoms does it cause?

They fall into the three groups above: pressure on sight, pressure on the nerves that move your eyes, and hormones.

From pressure, the common ones are headaches and trouble seeing, especially at the edges of your vision. Eye movements can be affected too, which shows up as double vision or an eyelid you cannot fully open.

From too little hormone, the list is long and vague, which is exactly why it gets missed: feeling tired, feeling weak, feeling dizzy, dry skin, periods that change or stop, and loss of interest in sex. None of it points at your head.

From too much hormone, what you notice depends on which one.

• Prolactin. Periods that become irregular or stop, milk from the breasts when you are not feeding a baby, and in men, trouble with erections. A tumor making prolactin is called a prolactinoma.
• Growth hormone. Hands, feet and facial features that slowly change, often over years. Doctors call that acromegaly.
• ACTH, which tells the body to make a stress hormone. Weight gain around the face and middle, and other changes. Doctors call that Cushing's disease.

If you recognize something in that list, say so at your next appointment, even if it seems small. A lot of these are easy to explain away one at a time.

Two emergencies here have rules of their own. They come after the lists below.

When to call for help right now

Some things should not wait for the next appointment.

Call an ambulance for any of these. Call 911, or your local emergency number:

• A first ever seizure.
• A seizure that lasts more than five minutes.
• One seizure right after another, with no waking up in between.
• Someone who cannot be woken.
• Trouble breathing, or someone who seems to be choking.
• Suddenly not being able to speak, move one side, or see.

A seizure like the ones you usually have, that stops on its own, is not an ambulance call. What to do during a seizure draws the line.

Call your team the same day for any of these:

• A headache much worse than usual, or one that wakes you from sleep.
• Throwing up again and again.
• New weakness in the face, an arm or a leg.
• New trouble speaking, or understanding what people say.
• New confusion.
• Sleeping much more than being awake.
• A sudden change in your vision.

If you are having chemotherapy, a fever is its own rule. It means calling your team right away, at any hour, not waiting for the morning. An infection during chemotherapy can get dangerous fast, and it is treatable when it is caught early. The fever rule explains why, and what number your team will give you.

In the weeks after brain surgery, a fever is its own rule too, especially with a stiff neck or a bad headache. What comes after a craniotomy has the rest of that list.

If you have a shunt, the signs it has stopped working are their own rule. For you, everything on the same-day list above is a right-away call instead, and so are a few other signs. Get help right away, at any hour: call your team, or go to the emergency department. Signs a shunt is not working has the full list.

If you are not sure whether to call, call. Nobody on that team minds a phone call that turns out to be nothing.

Same day means today, not the next clinic appointment. Ask your team now for the after-hours number, and put it somewhere you will find it at two in the morning rather than somewhere sensible.

What to do during a seizure has the step-by-step, and getting help now is the short version to keep on a phone.

This tumor has two emergencies of its own, and the list above does not cover them. Both are worth reading once now rather than looking up at two in the morning.

A sudden, severe headache. Sometimes a pituitary tumor bleeds, or loses its blood supply. Doctors call it apoplexy. The headache comes on suddenly, often behind the eyes, and it is the most common sign of it. It can come on its own. It can also come with sight that drops, double vision, a drooping eyelid, feeling sick to your stomach, passing out, or feeling confused. This one cannot wait for morning. Call 911, or your local emergency number, or go straight to the emergency department. This needs a scan and treatment that a phone call cannot give you. Tell your team as well, at whatever hour it is. It is treated, and treating it early is what protects your sight.

If you take steroid replacement, being ill is its own rule. When the gland cannot make the hormone that tells your body to produce its stress hormone, a plain illness can become dangerous. So can an infection, an operation, or an accident. The Endocrine Society calls that an adrenal crisis, and says that without treatment it can kill.

The signs are being very sick to your stomach, confusion, and feeling faint or passing out. If those are happening now, that is an emergency: call 911, or your local emergency number. If you have been given an emergency injection, that is what it is for, and the Endocrine Society says you still go straight to a hospital afterwards. Ask your team now for your own plan: what to do when you are ill, what to do if you are throwing up and cannot keep pills down, and whether you should carry an injection and wear a medical alert bracelet. Throwing up and not being able to keep pills down needs help the same hour, not the next day. Steroids covers the medicine itself, and carries the same rule for anyone on replacement.

You do not have to be on replacement for this to be yours. Some people find out they have the problem when a crisis is the first sign of it. If this tumor or an operation on it has hurt your gland, treat these signs the same way.

Both of these are uncommon. Both are worth telling the people you live with as well.

How do doctors find out it is this?

Blood tests and a scan, and usually a check of your sight.

Your team will take blood to measure hormone levels, because the answer changes the plan more than the size does. An MRI scan shows the gland and what is around it.

If the tumor is near the nerves for sight, you will be sent for a proper sight test. It is not the one you have at the eye doctor for glasses. It maps the outer edges of what you can see, which is where loss tends to start here, and it is repeated over time so small changes show up.

Some people need a further test that checks how the gland responds. Your team will tell you which.

Unlike most tumors on this site, a piece of tissue is not usually taken first. Here the blood tests and the scan often give the answer, and any tissue comes from the operation itself if there is one.

What do the words on my report mean?

Your report may carry two names for the same thing, and neither is a mistake.

Pituitary adenoma, and PitNET. The older name is adenoma. The World Health Organization now prefers pituitary neuroendocrine tumor, shortened to PitNET. You may see either, or both together.

That change is argued about, and the argument is worth knowing because it is about you. The editors of the medical journal for this field have objected in print. They say renaming these growths does not change what they are under a microscope, and does not change the outlook. Another review put the worry plainly: the new name risks needless worry for people whose tumor is not dangerous, because "tumor" sounds worse than "adenoma" did.

So if your report says PitNET and you read it as bad news, that reading is one that specialists themselves predicted and argued against.

Pituitary carcinoma, and metastatic PitNET. The same change renamed the rare cancerous form. Both names mean the same rare thing.

Diabetes insipidus, and arginine vasopressin deficiency. This one is the opposite story, and it is a good one.

Damage to the back of the gland can leave you very thirsty and passing a lot of water. It has nothing to do with diabetes of the sugar kind. That shared word caused real harm: people were admitted to the hospital, staff assumed the wrong illness, and treatment was held back. In 2022 a working group proposed a new name, arginine vasopressin deficiency, so the word "diabetes" would stop causing that mix-up. Eight hormone societies endorsed it, including the Pituitary Society.

They also said they would keep the old name in brackets for some years. So a report that says "arginine vasopressin deficiency (cranial diabetes insipidus)" is doing exactly what was intended.

Arginine vasopressin deficiency often follows the operation through the nose, which is why it is here.

Two renames on one page, made for opposite reasons. One, doctors argue, frightens people for no benefit. The other was made because a word was getting people hurt. Your paperwork may carry both.

Your pathology report goes through the document itself. It is written for reports that carry a grade and come from a piece of tissue, and yours may have neither.

How is it usually treated?

Three routes, and which one you get depends mostly on whether the tumor makes a hormone, and which.

Pills, for some. A tumor making prolactin is usually treated with medicine rather than surgery. The Endocrine Society says these tumors are mostly treated successfully that way. The pills lower the hormone and often shrink the growth, and the common side effects are feeling sick to your stomach and feeling dizzy. Surgery comes up if the medicine does not work.

Watching, for some. If the tumor is small, not growing and not causing symptoms, your team may follow it with scans and blood tests instead of treating it. Watching a tumor, step by step covers what that involves and why it is a plan rather than a delay.

Surgery, for some. It is usually advised when the tumor is affecting your sight or threatens to, when it is pressing on other nerves, when it is growing, or when it is causing headaches.

Radiation is used less often here, usually when some tumor is left behind or it comes back.

What is treatment actually like, and what is normal afterwards?

The operation goes through your nose

It is not like the brain operations described elsewhere on this site.

The surgeon reaches the gland through your nose and the sinus behind it. There is no cut in your scalp and no shaved head. The route is called transsphenoidal, after the sinus it passes through.

Afterwards, expect your nose to feel blocked and sore for a while, the way a bad cold feels. Tell your team about clear fluid running from your nose, which needs checking.

For a few people the tumor is too large or awkward for that route, and the surgeon goes through the scalp instead. Your team will say which one is planned and why.

What comes after an operation covers the general aftercare, though the nose route is gentler than the operation that page describes.

Hormones afterwards

Some people need hormone pills afterwards, sometimes for good, because the gland cannot make enough on its own. That is not a complication that went wrong. It is a known outcome and it is treatable.

If one of those is a steroid replacement, read the emergency rule further up this page again, and ask for your own written plan before you leave.

Tell your team if you are very thirsty and passing a lot of water. That often follows an operation on the pituitary. It can be arginine vasopressin deficiency, the second of the renames above, and there are other reasons for it too, which is why it is worth saying rather than working it out at home. Either way it is treated.

Sight often improves once the pressure is off, and your team will check it after the operation.

Everyday life

Day to day, life here turns on your hormones and your sight, the same as the rest of this page.

Two things are worth planning for. If you take hormone replacement, you need a routine for it and a plan for days when you are ill. And if your sight changed, have it checked properly before you drive, because the part that goes first is the part you use at intersections.

When what changed is your sight sets out what a field test can and cannot settle. Your own team is who to ask for the rule where you live.

Follow-up scans, and what to do while you wait

Follow-up here is scans and blood tests together, and often a sight test as well.

Scans continue for years and spread further apart if nothing changes. Follow-up scans explains how one scan is read against the last. Waiting for results is about the days in between.

Ask your team for your own timetable, and ask what would make it change.

If it comes back

Some tumors regrow, and there is usually something to do about it. The choices are the same three as before: pills, another operation, or radiation. Which one depends on what was used the first time and what is left.

Ask what each choice is meant to achieve, and make notes while you are being told.

Did I cause this?

What follows is written about brain tumors in general. This tumor is not one, as the top of this page says. But the question is the same, and so are the answers. It is worth reading as yours.

Almost everybody asks this, usually in the first week, usually in private. It is worth answering plainly.

For most brain tumors, nobody knows the cause. That is the honest state of it. The exact cause of most brain and spinal cord tumors is not fully understood, and there are very few well established risk factors. Tumors start when genes that control how cells grow and divide are changed, and in most cases those changes happen by chance during a person's life. Not because of something done or not done.

Cell phones. They give off a kind of radiation called radiofrequency. It is not the same as the radiation in an x-ray. The energy is too low to damage DNA, and it is not known to cause cancer. The evidence so far is that using a cell phone does not cause brain tumors.

Stress. There is no scientific evidence that stress causes brain tumors, and no data linking stress to a higher chance of getting one. A hard year before a diagnosis is a hard year. It is not a cause.

Something you ate, or did not eat. No food and no diet is an established cause of a brain tumor. It is not on the list of known risk factors at all.

Something you passed on, or caught. Brain tumors are not contagious. Most are not inherited either. A small number of people do have an inherited condition that raises the risk, and if that applies to you, your team will raise it and offer to talk it through.

If you are turning this over at three in the morning, that is ordinary and it happens to nearly everyone. It is also worth saying out loud to somebody on your team, because they have answered it many times and they would rather you asked.

What might happen over time

For the person caring for someone with this

If you are the one driving to the appointments, keeping track of the pills, and lying awake at night worrying about them, this part is for you.

You are allowed to ask questions. In one study, families said they were afraid of annoying the doctor by asking too much. One of them was told by a doctor to stop playing doctor. Ask anyway. Write your questions down before you go, and bring a notepad. Two people in the room hear more than one.

Ask who your first call is. Care comes from a lot of people at once, and it is easy to end up as the only one holding it together. Ask the team: who do I call first? Some teams have one person whose job this is, often a nurse. Get the name and the number.

Get two numbers, and know which one to use. One for work hours, one for nights and weekends. Then ask what counts as "call us today" and what counts as "call an ambulance" for this tumor, and write the answer down where you can see it. If you are not sure which it is, call. Nobody on that team will mind.

If they have seizures, read about them before you need to. What to do when someone has a seizure is the one to know by heart. Living with seizures is about the rest of the time: what is safe, what to change, and driving.

Ask to be shown anything you are sent home to do. In that same study, families were sent home to change dressings and give medicines with no training at all. That is not fair to you. Before you leave the hospital, ask someone to show you. Then do it once while they watch.

Say what you notice. You may see a change before they do. Changes in thinking, mood and behavior can show up to the people close by first. Telling the team is not going behind their back. It is something the team cannot learn any other way.

Look after yourself, and let people help. Eat, sleep, and keep your own appointments. Take a little of the day back for yourself. When someone asks what they can do, give them a real job: a meal, a ride, an hour with the kids. Most people want to help and do not know how to offer.

You can talk to somebody about all of this today. See where to get help.

Two things are specific to this tumor.

Learn the two emergency rules with them. A sudden, severe headache, and being ill while on steroid replacement. You may be the one who notices first, and neither can wait for morning.

Hormone changes can look like mood or personality. Tiredness, low mood and loss of interest can all come from a gland that is not working, not from someone giving up. It is worth saying to the team rather than absorbing at home.

What to ask your team

• Is my tumor making a hormone, and which one?
• Has my sight been checked, and when will it be checked again?
• Is the plan pills, surgery, or watching, and why that one?
• My tumor makes a hormone. Which of those three does that point to for me?
• If it is surgery, will it be through the nose?
• Will I need hormone replacement afterwards?
• If I need steroid replacement, what is my plan for days when I am ill?
• Should I carry an emergency injection or wear a medical alert bracelet?
• What would make you want me to call before the next appointment?
• Who do I call after hours, and what is the number?

Where to get support

• Getting help now, for the day when you need a person rather than a page.
• The Pituitary Society publishes patient material on these tumors and the conditions they cause.
• The Endocrine Society has a patient library covering the hormone side, and a directory for finding a hormone specialist.
• The specialist nurse on your team. Most people find that is the fastest route to a real answer.