Pituitary Tumor

What is pituitary tumor?

A pituitary tumor is an abnormal growth of cells in the pituitary gland. The pituitary gland is a small, pea-sized organ that sits at the base of the brain, just behind the bridge of the nose. It is often called the “master gland” because it releases hormones (chemical messengers that travel through the blood) that control many other glands, including the thyroid, the adrenal glands, the ovaries and the testicles.

The large majority of pituitary tumors are benign, which means they are not cancer and do not spread to other parts of the body. Doctors usually call these growths pituitary adenomas. Even though they are not cancer, they can still cause problems in two main ways: by producing too much of a hormone, or by pressing on the gland and nearby structures such as the nerves that carry signals from the eyes to the brain.

Pituitary tumors are grouped in several ways. By size, a tumor smaller than about one centimeter is called a microadenoma, and a tumor larger than that is called a macroadenoma. By behavior, a tumor is described as functioning (it makes excess hormone) or non-functioning (it does not make excess hormone, and problems come from its size). Common functioning types include prolactinomas, which make too much prolactin; growth-hormone-secreting tumors, which cause a condition called acromegaly in adults; and ACTH-secreting tumors, which lead to Cushing disease.

Pituitary tumors can occur at any age but are found most often in adults. Many small pituitary tumors never cause symptoms and are discovered by chance when a brain scan is done for another reason. Care for these tumors usually involves an endocrinologist (a doctor who specializes in hormones) working together with specialists in neurology, neurosurgery, eye care and, when needed, radiation treatment.

Pituitary tumor symptoms

Pituitary tumor symptoms depend mainly on whether the tumor produces hormones, how large it is and how quickly it grows. Some people have no symptoms at all. Others develop a mix of hormone-related and pressure-related problems that build up slowly over months or years, which is one reason the condition is often diagnosed late.

Symptoms caused by pressure from a larger tumor may include:

• Headaches, often persistent and not clearly linked to another cause
• Loss of side (peripheral) vision, sometimes noticed as bumping into objects or difficulty seeing in a car mirror
• Blurred or double vision
• Drooping eyelid or trouble moving one eye
• Nausea or vomiting

Symptoms caused by too little normal pituitary hormone, because the tumor is crowding out healthy gland tissue, may include:

• Unusual tiredness and weakness
• Feeling cold, or unexplained weight change
• Loss of interest in sex, erectile difficulty or irregular or absent menstrual periods
• Low blood pressure or dizziness
• Increased thirst and urination

Symptoms caused by too much of a specific hormone vary with the hormone involved. A prolactinoma can lead to milky breast discharge (in women and sometimes men), absent periods and infertility. Excess growth hormone in adults can cause gradual enlargement of the hands, feet and facial features, joint pain, thickened skin and sweating; in children it can cause unusually tall stature. Excess ACTH (a hormone that stimulates the adrenal glands) leads to Cushing disease, with weight gain around the abdomen and face, a rounded face, easy bruising, purple stretch marks, muscle weakness, high blood pressure and high blood sugar. Rarely, a tumor that makes thyroid-stimulating hormone causes symptoms of an overactive thyroid, such as rapid heartbeat, nervousness and weight loss.

Because these changes appear slowly, they are frequently mistaken for normal aging, stress or other common conditions. Vision changes and headaches tend to appear with larger tumors, while hormone symptoms may appear even when the tumor is very small.

Causes and risk factors

In most cases the exact pituitary tumor causes are not known. Researchers believe that tumors begin when changes (mutations) occur in the genetic material of a single pituitary cell, causing it to multiply when it should not. In the great majority of people these changes happen by chance during life and are not passed down from parents.

A small number of pituitary tumors are linked to inherited conditions that run in families. These include:

• Multiple endocrine neoplasia type 1 (MEN1), a condition that causes tumors in several hormone-producing glands
• Multiple endocrine neoplasia type 4 (MEN4)
• Carney complex
• Familial isolated pituitary adenoma (FIPA), in which pituitary tumors occur in more than one family member
• McCune-Albright syndrome

Recognized risk factors are limited. Having a close relative with one of the inherited conditions above raises the chance of developing a pituitary tumor. Age is a factor in the sense that these tumors are found more often in adults than in children, although they can occur at any age. Unlike many other tumors, pituitary tumors have not been clearly linked to lifestyle factors such as smoking, diet, alcohol or exposure to particular chemicals, and there is no evidence that stress, injury or infection causes them. Having a risk factor does not mean a tumor will develop, and many people with a pituitary tumor have no identifiable risk factor at all.

Pituitary tumor diagnosis

Pituitary tumor diagnosis usually begins when a doctor notices a pattern of symptoms that points toward a hormone problem or toward pressure at the base of the brain. Because the symptoms overlap with many other conditions, confirming the diagnosis normally requires several kinds of tests.

• Medical history and physical examination. The doctor asks about headaches, vision changes, menstrual and sexual function, energy levels and changes in appearance, and examines features such as skin, body shape and reflexes.
• Blood and urine tests. These measure levels of pituitary hormones and the hormones they control, such as prolactin, growth hormone, IGF-1 (a marker of growth hormone activity), cortisol, thyroid hormones and sex hormones. Some tests are done at specific times of day, or after giving a substance that should normally raise or lower a hormone, to see how the gland responds. A 24-hour urine collection or a late-night saliva test may be used to check cortisol.
• Magnetic resonance imaging (MRI). MRI uses magnets and radio waves to create detailed pictures of the brain. A dedicated pituitary MRI, often with a contrast dye injected into a vein, is the main imaging test. It can show the size of the tumor and whether it is pressing on nearby structures. Computed tomography (CT), a type of detailed X-ray scan, may be used when MRI is not possible.
• Vision testing. An eye specialist may test how wide the field of vision is, because a tumor can press on the optic nerves and cause loss of side vision that the person has not noticed.
• Tissue examination. When surgery is performed, a pathologist studies the removed tissue under a microscope to confirm the tumor type and which hormones, if any, it produces.

Doctors combine these results to decide whether a tumor is functioning or non-functioning, how large it is, and whether it is affecting vision or normal pituitary function. Sometimes an MRI done for another reason shows a small pituitary growth in a person with no symptoms. In these situations the doctor usually orders hormone tests to check whether the growth is active, and may recommend repeat imaging over time rather than immediate treatment.

Pituitary tumor treatment options

Pituitary tumor treatment options depend on the type of tumor, its size, whether it makes hormones, whether it is affecting vision, the person’s age and general health, and personal preferences. Care is usually planned by a team that may include an endocrinologist, a neurosurgeon, a radiation oncologist and an eye specialist. At Acibadem, this coordination typically involves the endocrinology, neurosurgery and neurology departments. The main approaches are described below.

• Observation (watchful waiting). Small tumors that do not produce excess hormone and do not press on nearby structures often need no immediate treatment. Instead, the doctor may arrange regular MRI scans, hormone tests and vision checks to watch for change. Many such tumors remain stable for years.
• Medication. Drugs are the first-line treatment for most prolactinomas. Medicines called dopamine agonists can lower prolactin levels and often shrink the tumor. For growth-hormone-producing tumors, drugs such as somatostatin analogs or growth-hormone-receptor blockers may be used, usually when surgery has not fully controlled hormone levels. Medications that reduce cortisol production may be used in Cushing disease. Medicines are also used to replace hormones that the damaged pituitary gland can no longer make.
• Surgery. Surgery is often recommended when a tumor is pressing on the optic nerves, when it produces excess growth hormone or ACTH, or when medication has not worked. The most common operation is transsphenoidal surgery, in which the surgeon reaches the pituitary gland through the nose and the sphenoid sinus (an air space behind the nose) using an endoscope, a thin tube with a camera. This approach avoids opening the skull and leaves no visible scar. Occasionally a very large tumor requires an operation through the skull (craniotomy). Possible risks include bleeding, leakage of the fluid that surrounds the brain, infection, and damage to the normal pituitary gland leading to hormone deficiencies that need lifelong replacement.
• Radiation therapy. Radiation uses high-energy beams to damage tumor cells. It may be used when tumor tissue remains after surgery, when the tumor returns, or when surgery is not suitable. Options include conventional radiation given in daily sessions over several weeks and stereotactic radiosurgery, a highly focused single or short-course treatment. Radiation acts slowly, so hormone levels may take months or years to fall, and it can gradually reduce normal pituitary function over time.
• Hormone replacement and follow-up care. If the tumor or its treatment reduces normal pituitary function, doctors prescribe replacement hormones such as thyroid hormone, cortisol, sex hormones or growth hormone. Long-term follow-up with periodic blood tests and imaging is a standard part of care for almost everyone with a pituitary tumor, whatever the initial treatment.

Rehabilitation may be helpful for some people, for example vision rehabilitation if sight has been affected, or physical therapy for joint problems related to acromegaly. Your doctor may combine several of these approaches over time, and the plan is often adjusted as test results change.

Living with pituitary tumor and outlook

For most people, a pituitary tumor is a long-term condition to be managed rather than a life-threatening illness. Because nearly all pituitary tumors are benign, the outlook is generally favorable, especially when the tumor is found before it has caused permanent damage to vision or to the gland. Many people return to their normal activities after treatment, although recovery times vary.

Outcomes depend on several factors. Small tumors that are fully removed by surgery often do not return, but some tumors, particularly larger ones that have grown into surrounding tissue, cannot be removed completely and may need additional treatment or monitoring. Hormone problems caused by functioning tumors frequently improve after successful treatment, but some changes, such as bone enlargement in acromegaly, may not fully reverse. Vision loss often improves if pressure on the optic nerves is relieved promptly, but long-standing damage can be permanent.

Living with a pituitary tumor commonly means regular appointments for blood tests and scans, and for some people it means taking replacement hormones every day for life. People who take cortisol replacement need to understand how to increase the dose during illness and when to seek help, since a sudden shortage of cortisol can be dangerous. Fatigue, mood changes and difficulty with concentration are reported by some people even after successful treatment, and it is reasonable to raise these with the care team. Fertility questions are also common and are usually addressed with an endocrinologist, because several treatments can affect the ability to have children. Support from family, and from patient organizations for pituitary conditions, can help with the practical and emotional side of ongoing care.

Frequently asked questions

What is a pituitary tumor and is it cancer?

A pituitary tumor is an abnormal growth of cells in the pituitary gland at the base of the brain. The vast majority are benign, meaning they are not cancer and do not spread to other organs. Cancerous pituitary tumors, called pituitary carcinomas, are extremely rare. However, a benign tumor can still cause significant problems by producing excess hormones or by pressing on nearby nerves and the normal gland.

What are the first pituitary tumor symptoms people notice?

Early pituitary tumor symptoms vary widely and are often subtle. Many people first notice hormone-related changes such as irregular or absent periods, milky breast discharge, reduced interest in sex, unexplained fatigue or gradual changes in the shape of the face, hands or feet. Others first notice headaches or difficulty with side vision. Because these signs develop slowly and overlap with other conditions, they are easy to overlook, and only a medical evaluation can determine the cause.

What are the main pituitary tumor causes?

In most cases the cause is unknown. The tumor is thought to start when a single pituitary cell develops a genetic change that makes it multiply abnormally. These changes usually occur by chance and are not inherited. A small proportion of pituitary tumors are linked to inherited conditions such as multiple endocrine neoplasia type 1, and in those families testing of relatives may be considered. Lifestyle factors have not been shown to cause pituitary tumors.

How is pituitary tumor diagnosis confirmed?

Pituitary tumor diagnosis is confirmed by combining blood or urine tests that measure hormone levels with an MRI scan of the pituitary gland. Hormone tests show whether the tumor is producing excess hormone or whether the normal gland is underactive, while the MRI shows the size and position of the growth. Vision field testing is often added if the tumor is large. When surgery is performed, examination of the removed tissue confirms the exact type.

What are the pituitary tumor treatment options if the tumor is small?

Small tumors that do not produce hormones and are not affecting vision are often simply monitored with regular MRI scans and hormone tests, an approach known as watchful waiting. If a small tumor is a prolactinoma, medication is usually the first treatment and may shrink it. Surgery is generally reserved for small tumors that produce growth hormone or ACTH, or for tumors that grow or start causing symptoms during monitoring. The decision is individual and is made together with your doctor.

Can a pituitary tumor come back after treatment?

Yes, some pituitary tumors return after surgery or medication, particularly larger tumors or those that could not be removed completely. For this reason, long-term follow-up with periodic scans and hormone tests is recommended for most people, even after apparently successful treatment. If a tumor does return, options such as repeat surgery, medication or radiation therapy may be considered depending on the situation.

Does a pituitary tumor affect fertility or pregnancy?

It can. Some pituitary tumors, especially prolactinomas, interfere with the hormones that control ovulation and sperm production, which may cause infertility. Treating the tumor often restores fertility, although this is not guaranteed. Pregnancy in a person with a known pituitary tumor generally needs closer monitoring, because pregnancy hormones can cause some tumors to enlarge. An endocrinologist can advise on medications and monitoring before and during pregnancy.

When to see a doctor

Many pituitary tumor symptoms develop gradually, and it is reasonable to arrange a medical evaluation if you notice persistent changes such as new or worsening headaches, unexplained fatigue, changes in menstrual periods or sexual function, breast discharge not related to breastfeeding, gradual enlargement of the hands, feet or facial features, unexplained weight gain with easy bruising, or any change in your vision. These symptoms have many possible causes, and a doctor can arrange the appropriate tests.

Some situations are urgent and need emergency medical care because they may indicate bleeding into the tumor (a condition called pituitary apoplexy) or a dangerous shortage of cortisol. Seek immediate help for:

• A sudden, severe headache, especially if it is described as the worst headache of your life
• Sudden loss of vision, sudden double vision or new difficulty moving the eyes
• Severe nausea and vomiting together with headache
• Confusion, extreme drowsiness or fainting
• A stiff neck or sensitivity to light with headache
• In someone taking cortisol replacement or known to have low cortisol: severe weakness, vomiting, low blood pressure, dizziness on standing or collapse, particularly during another illness
• Signs of a leak of clear fluid from the nose after pituitary surgery, or fever and headache after surgery

Anyone already being monitored for a pituitary tumor should report new or worsening symptoms between scheduled visits rather than waiting for the next appointment, as changes may indicate that the tumor has grown or that hormone levels have shifted.