Pituitary Tumors and Diseases

Pituitary tumors are abnormal growths that can develop in your pituitary gland, causing excessive production of certain hormones (secretory) or inhibit pituitary function (non-secretory) and even sometimes can do both overproduce a hormone and inhibit others.
Your pituitary gland is a pea-sized gland that’s located at the base of your brain.
Although it’s small, your pituitary gland is mighty – it’s known as the “master gland” because it’s responsible for regulating the activities of other glands in your endocrine system. Your pituitary gland releases hormones that regulate most of the endocrine glands such as thyroid, adrenal, testes/ovaries and general growth and prolactin, which is specialized for milk production in the woman who is breastfeeding.

Symptoms of a Pituitary Tumor

Pituitary tumors may cause symptoms that usually develop gradually. Some of the symptoms of pituitary tumors are subtle, such as fatigue and weakness so many people overlook their symptoms. Sometimes when you have a pituitary tumor, your body produces excessive amounts of certain hormones (which hormones it overproduces depends on the tumor). For example, pituitary tumors can make too much growth hormone (acromegaly), too much thyroid-stimulating hormone (hyperthyroidism), too much ACTH (Cushing’s disease), too much sex hormone (virilization or Infertility) or too much prolactin (galactorrhea or breast milk). Most pituitary tumors are less than 1cm and are called microadenomas. But larger tumors (> 1cm) are called macroadenomas. These large tumors can put pressure on your pituitary gland and surrounding tissues which cause loss of hormone production or changes in your vision, such as loss of peripheral vision. These large tumors can also suppress the pituitary from making hormones and cause deficiencies such as loss of growth hormone, loss of LH/FSH (sex hormones), loss of ACTH (adrenal insufficiency), or loss of thyroid hormone (hypothyroidism).

Causes of Pituitary Tumors

Most pituitary tumors are benign (non-cancerous) and no one really knows for sure what causes most pituitary tumors to develop on your pituitary gland. However, some pituitary tumors may be hereditary. There are very few known risk factors for pituitary tumors. The main risk factors are age and family history of certain genetic conditions. When pituitary tumors run in families, there are several genes that your doctor may want to test to see if that is what is causing the tumor. A small number of pituitary tumors are caused by a rare genetic disorder called multiple endocrine neoplasia type 1 (MEN 1). This endocrine disorder can lead to over-activity or enlargement of four different endocrine-related glands, including the pituitary, parathyroid, pancreas or gastric hormones. Another rare cause of pituitary tumors is multiple endocrine neoplasia type 2 (MEN 2) which is associated with a rare thyroid cancer, adrenal tumor, and possible parathyroid disease. If you have a pituitary tumor, your doctor may do a genetic blood test to rule out MEN 1 or MEN 2. But as far as non-hereditary pituitary tumors, the cause remains unknown. In most cases, scientists are unsure what causes the uncontrolled growth of certain cells that leads to a pituitary tumor.
What we do know is that pituitary tumors cause certain hormones to be produced excessively and some tumors are destructive, causing certain hormones to be deficient. Because pituitary tumors have very few known risk factors, it’s difficult to prevent them. It is also sometimes difficult to detect them because symptoms of pituitary tumors can be subtle. But researchers are hard at work to try to understand why certain people – who don’t have the main risk factors of pituitary tumors – can develop them anyway.

Diagnosing Pituitary Tumors

About 10% of all people will develop a pituitary adenoma (benign tumor) at some point in their lives, but most pituitary tumors do not cause any symptoms – and most are never even diagnosed or ever cause a clinical problem. We call these tumors “incidentalomas”.

Before performing any tests, we will obtain your complete health history and ask about your symptoms. A detailed family health history may aid the provider because some pituitary tumors are linked to certain genetic conditions, which can be passed from generation to generation. A physical exam is very important to assess either over or under function of pituitary hormones.

Although a lot can be learned during the history and exam part of your doctor’s visit, you will need to run some simple tests:

• Blood and urine tests: These tests can determine whether you have an excessive amount – or a deficiency – of certain hormones. We will look for abnormal adrenal and thyroid hormone levels, for example.
• Imaging tests: A magnetic resonance imaging (MRI) scan of your brain can show the location, size, and shape of a pituitary tumor. Sometimes a computerized tomography (CT) scan will be done instead.
• Formal visual fields: These tests can help determine if a pituitary tumor is impacting your vision, especially your peripheral vision.

Being diagnosed with a pituitary tumor doesn’t mean that you have cancer. In fact, most pituitary tumors are benign (non-cancerous), which means that they won’t spread. However, it’s important to diagnose pituitary tumors early on to prevent possible complications of a pituitary tumor. Although most pituitary tumors are benign (non-cancerous) some pituitary tumors do cause complications. You may be able to prevent these complications if you recognize the symptoms of a pituitary tumor and get treatment for it early on. One of the most serious pituitary tumor complications is loss of some vision or even blindness. This can happen if a tumor puts too much pressure on your optic nerve. These nerves are very close to your pituitary gland. Not everyone who has a pituitary tumor will have vision problems, however testing for usual field problems are done in most patients with a pituitary problem. Tumor growth and vision loss usually happen very gradually, so most patients do not notice an abrupt change in vision.

Other potential pituitary tumor complications include:

• Diabetes Insipidus: This type of diabetes is mostly associated with larger pituitary tumors (macroadenomas) and is not to be confused with type 1 or type 2 diabetes which causes an increase in your blood glucose level. Diabetes insipidus occurs when your pituitary gland and the gland found just above it, the hypothalamus, don’t produce enough of a hormone vasopressin (ADH), that’s in charge of maintaining the body’s water and salt balance. The most common symptom is constant thirst, which can lead to frequent bathroom stops from drinking too much fluids. This is because without vasopressin, the kidneys aren’t able to hold onto water as they should and you get dehydrated, triggering you to be thirsty. This condition can also be a complication of some pituitary tumor treatments.

Permanent hormone deficiency: It’s possible for a pituitary tumor to cause a permanent hormone imbalance. If this happens, you may need to take medications to replace the lost hormone. For example, if your pituitary tumor causes a thyroid-stimulating hormone (TSH) deficiency, you may need to take thyroid replacement to get your thyroid levels back to normal.

Pituitary apoplexy: This is a rare but serious complication that causes sudden bleeding into the pituitary tumor. Pituitary apoplexy typically needs immediate treatment – usually medicines such as corticosteroids and/or surgery. Symptoms include a severe headache and vision problems, such as double vision or vision loss. You can also have symptoms of hypopituitarism (when your pituitary gland releases low amounts of certain hormones). Symptoms of hypopituitarism can include excessive thirst (from diabetes insipidus), lightheadedness (from adrenal insufficiency), and cold intolerance (from hypothyroidism).

These are just some of the possible symptoms and complications you may experience if you have a pituitary tumor, but many people with pituitary tumors don’t experience any problems.
However, if you have been diagnosed with a pituitary tumor and you notice sudden, unusual changes in your health, you should ask your doctor if they could be related to your pituitary tumor. Getting proper treatment for your pituitary tumor can prevent complications from getting worse.

Pituitary Tumor Treatment

Treatment for pituitary tumors usually depends on what type of tumor it is, including its size and shape. Generally, pituitary tumor treatment involves a combination of treatments to control the tumor or remove it: medication, surgery and/or radiation therapy. The main goals of all of these treatments are the same; to return your hormone levels to normal if possible and to treat any symptoms caused by the size of the tumor (which means that you may need surgery to remove the tumor, radiation to kill the tumor or medical treatment to shrink your tumor).

To treat a pituitary tumor medications are sometimes used to help block too much of a certain hormone being produced. What medications you take depends on what hormone is being overproduced and there are some medications that may shrink pituitary tumors.
Surgery may be used to cure or remove some pituitary tumors, such as those less than 1 cm. Surgery may be necessary if the tumor is large and pressing on your optic nerves, which can decompress the pressure on the optic nerve and therefore prevent or improve the loss of vision.
Radiation therapy may also be used to treat your tumor. Using high-energy x-rays or gamma rays to shrink your tumor, radiation therapy can be used alone or in combination with surgery. It’s especially useful if a tumor persists or returns even after surgery.

Treating a pituitary tumor isn’t the same for everyone. For example, you may only need to take medications to normalize your hormone levels and shrink your tumor, or you may need to use all 3 treatments. It really depends on what type of tumor you have. Additionally, if one type of treatment doesn’t work to control your tumor, you may need to try another treatment. For instance, medications may be used if surgery is unsuccessful in normalizing your hormone production. If your tumor grows back after surgery, you may need radiation therapy to prevent further growth.

Another thing to keep in mind is that treating a pituitary tumor isn’t always appropriate, especially if you’re older or are in poor health. However, many people who have pituitary tumors (no matter what their age or how healthy they are) can function normally without their tumor causing any problems or ever needing treatment for it.

It’s important to note that you may need to take hormone replacement medication – even after your pituitary tumor has been successfully treated- because of decreased hormone production, either directly caused by the pituitary tumor, the removal of a pituitary tumor or secondary to radiation damage to the pituitary.

Medications for Pituitary Tumors

Pituitary tumor medications are one of the most common treatments for pituitary tumors. Although the type of treatment you receive typically depends on what type of tumor you have – including the size and shape of it- certain medications may be effective on their own in treating your tumor. These medications work to return your hormone levels to normal and shrink the size of your tumor. This is important because if your tumor is too large (more than 10 mm), it can put pressure on your optic nerve, potentially leading to vision loss or blindness.

Bromocriptine and Cabergoline

Bromocriptine (brand name: Parlodel) and cabergoline (brand name: Dostinex) treat prolactin-secreting tumors, which are called prolactinomas. These medications work to reduce your prolactin levels and can shrink your tumor. In most cases, these drugs are so useful that surgery isn’t needed.

Octreotide, Lanreotide and Pegvisomant

Usually used to treat growth hormone-secreting tumors, octreotide (brand name: Sandostatin LAR), lanreotide (brand name: Somatuline), and pegvisomant (brand name: Somavert) can reduce the size of your pituitary tumor by decreasing growth hormone production (octreotide and lanreotide) or blocking its action (pegvisomant). If surgery doesn’t normalize the production of growth hormone, these drugs can help do that or at least block its activity.
Medications can be extremely useful in treating pituitary tumors, but sometimes they’re not enough to shrink your tumor or regulate your hormone production. That’s why there are other treatment options for pituitary tumors: radiation therapy and surgery.

Radiation Therapy for Pituitary Tumors

If you’ve been diagnosed with a pituitary tumor, you’ll most likely need some type of treatment to reduce the size of your tumor and normalize your hormone levels. Radiation therapy for pituitary tumors can achieve these goals. Radiation therapy is not usually the first treatment tried for pituitary tumors – most often it’s used in combination with surgery or after other medical treatments has failed. Radiation therapy uses special x-rays or gamma rays to shrink your tumor, and it can be used after surgery or on its own. It’s especially useful when all of your tumor can’t be safely removed by surgery, if your tumor returns after you’ve had surgery, or if it causes symptoms that medication can’t treat.

There are 2 main types of radiation therapy: external beam radiation therapy and stereotactic radiosurgery. Your doctor will let you know which type is right for you and very specific radiation may require referral to a specific institution which specializes in the treatment. External beam radiation delivers small doses of radiation to the tumor to shrink it and is usually performed as a series of treatments done five times a week over a month and a half. Although it is generally very useful in treating pituitary tumors, it make take years to fully shrink your tumor and regulate hormone production. However, external beam radiation therapy can damage the healthy cells of the pituitary gland (panhypopituitarism) and brain tissue, which is a risk to discuss with your doctor. Stereotactic radiosurgery uses special brain-imaging techniques and radiation beams, which are the exact shape and size of your tumor, to target the tumor. There is a minimal amount of radiation and it is concentrated on the tumor, so there’s less damage to healthy tissues near the pituitary gland. But like external beam radiation therapy, the benefits of this treatment aren’t instant, and there are some drawbacks: In some people, it can take months or even years for this treatment to fully work. Also, doctors can’t use it if the pituitary tumor is too close to your optic nerves. If these nerves are damaged, it can lead to blindness.

Surgery for Pituitary Tumors

Pituitary tumor surgery involves removing all or most of the tumor that’s growing in the pituitary gland. But what type of surgery you have depends on the type of pituitary tumor you have, as well as the tumor’s size and shape.

Surgery is typically needed for 2 reasons:
1. If the tumor is pressing on your optic nerves, which can potentially lead to blindness
2. If the tumor is producing too much of a certain hormone (e.g., growth hormone or cortisol), which can cause and endocrine disorder (e.g. acromegaly or Cushing’s disease) and are amenable to surgery.

These are 2 main types of surgery for pituitary tumors:
1. Endoscopic transnasal transsphenoidal approach: Although “endoscopic transnasal transsphenoidal” is hard to pronounce, it’s easy to understand. The pituitary sits at the base of the brain just above the back of the nose. With this surgery, a team of surgeons (Neurosurgery and an Ear, Nose, Throat (ENT) surgeon) use special microsurgical tools to remove your tumor through your nose (transnasal) and sinuses (transsphenoidal). One of the tools your doctor will use is called an endoscope, which is a tiny video camera that helps guide your surgeon during surgery. Many patients like this option because there is no visible incision, which means no scar and patients typically leave the hospital in 2-3 days. Generally no other part of your brain is touched. However, extremely large pituitary tumors may be too hard to remove with this type of surgery, especially if they’ve spread to healthy tissue.

2. Transcranial approach: This surgery is a type of craniotomy (brain surgery). Cranium means skull, so craniotomy is brain surgery that involves reaching your tumor through an incision on the side of your cranium or forehead. A Neurosurgeon will remove your pituitary tumor through a small incision in the upper part of your skull – that’s why it is called transcranial (which means through your skull). With this approach, it’s much easier to reach larger tumors.

Surgery to remove a pituitary tumor typically takes about 3 hours, and most patients leave the hospital within several days. For the first few weeks after surgery, you may feel tired, have a headache, or slight nasal congestion, but these symptoms should gradually improve. And within 2 weeks, you should be back to your normal daily activities, including work.

Removing a pituitary tumor may cause abnormal hormone levels. That’s because your pituitary gland may produce lower levels of some hormones (e.g. thyroid-stimulating hormone) once the tumor is gone. To get your hormone levels back to normal – and to keep them there – you’ll most likely need frequent endocrine testing and possibly need to take hormone replacements.
Pituitary tumor surgery is considered low-risk for young, healthy people. However if you are older or have other medical problems, your surgical risks increase, and these risks need to be balanced against the expected benefits of surgery. It’s important to talk to your doctor about whether surgery is a good option for you.

With any surgery or radiation therapy, specific tests are required to monitor pituitary function. For example, pre and post-operatively, full pituitary testing is required to assess potential damage to the pituitary. When a radiation is used, yearly endocrine testing of the pituitary may be required for 10 years or more.