What are pituitary tumors?
Pituitary tumors are abnormal growths that develop on your pituitary gland. Some pituitary tumors are high in hormones that regulate the vital functions of your body. Some of these tumors cause your pituitary gland to make low levels of hormones.
Most of these tumors are non-cancerous growths (adenomas). Adenomas are found in the pituitary gland or surrounding tissues and do not spread to other parts of your body.
There are several options for treating pituitary tumors, such as removing the tumor, controlling its growth, and maintaining your hormone level with medications.
The pituitary gland, also known as the “master” gland, is a pea-sized gland that is important for the functioning of the human body. It is located behind the eyes and in front of the brain.
The pituitary gland produces hormones that regulate complex glands and organs of the body:
- Thyroid gland
- Kidney glands
Tumors that form in the pituitary gland are very rare and are generally not cancerous or benign. Most are considered “functional,” which means that they produce hormones. Tumors that do not produce hormones are called “dysfunctional.”
According to the American Cancer Society, some of the 10,000 tumors estimated to be diagnosed in 2016 will be cancerous.
- Pituitary Adenoma
Types of pituitary tumors
Pituitary tumors are almost always benign or cancer-free. Benign tumors are called adenomas. Adenomas range from a few millimeters to several centimeters. Microdenomas smaller than 1 cm in diameter (the size of a dime) is called macroadenomas that are larger than 1 cm.
At least half of pituitary adenomas are dysfunctional, which means they do not cause the level of pituitary hormones in your body to increase. However, dysfunctional tumors can grow large enough to cause symptoms such as headaches or vision problems when they are pressed on the nerves that lead from the eyes to the brain. Sometimes pituitary hormone levels drop if they hit the pituitary gland.
Functional pituitary tumors produce elevated levels of one of the above hormones, which can lead to certain hormonal conditions. They grow large enough to cause other symptoms, including headaches and vision problems. Some functional tumors increase in size as the tissue of the pituitary gland shrinks, while the secretion of other pituitary hormones decreases.
Carcinoma or cancer of the pituitary
Cancer or rare malignant pituitary tumors are functional or inactive. Malignant tumors, also known as pituitary carcinomas, destroy pituitary tissue and cause a decrease in hormone levels. If left untreated, pituitary cancer can affect vision, cause headaches, and eventually spread to the brain or other parts of the body.
Causes of pituitary tumors
Scientists don’t know what causes most pituitary tumors. In recent years, they have made great strides in understanding how certain changes in a person’s DNA can cause pituitary cells to produce a tumor. DNA is a chemical in every cell in our body that makes up our genes – instructions for how our cells work. We generally resemble our parents because they are the source of our DNA. But DNA affects us more than how we see it.
As cells grow, some genes control them to divide into new cells and die. Oncogenes are genes that help cells grow, divide, and stay alive. Genes that slow down cell division or kill cells at the right time are called tumor suppressor genes. Tumors are caused by changes in DNA that activate oncogenes or inhibit tumor suppressor genes.
Some people inherit genetic mutations (changes) from their parents that greatly increase the risk of developing pituitary tumors. Some of these mutations are described in the risk factors for pituitary tumors. Genetic testing can be done to determine if family members with these genetic syndromes are affected.
But often, genetic mutations occur in life rather than being inherited. In some types of cancer, these mutations can be caused by external exposure to radiation or carcinogenic chemicals. Most pituitary tumors are not cancerous and there are no environmental causes for these tumors. Genetic changes in these tumors can be random events that sometimes occur when a cell divides, without an external cause.
Some non-hereditary (scattered) pituitary tumors, which do not run in families, have mutations in a gene called AIP. Many growth hormone-secreting adenomas have a mutation in a gene called GNAS1. These mutations are very rare in other types of pituitary adenomas.
Changes in other genes have been found in other types of pituitary adenomas, but it is not clear whether abnormal genes are always necessary for the formation of pituitary tumors. What is known is that damage to the regulatory mechanism generally prevents pituitary cells from growing and producing more hormones.
Since there are no known environmental or lifestyle causes of pituitary tumors, it is important to remember that people with these tumors cannot do anything to prevent them.
Symptoms of pituitary tumors
The symptom may be caused by a different medical condition that does not have a pituitary gland tumor.
- Eyesight problems
- Indescribable fatigue
- Humor changes
- Changes in structural cycles in women
- Erectile dysfunction is caused by the inability of men to achieve or maintain an erection and hormonal changes
- Infertility, which is the inability to have children
- Inadequate breast growth or breast milk production
- Cushing’s syndrome is a combination of minor injuries caused by weight gain, high blood pressure, diabetes, and high production of the hormone ACTH (see below)
- Acromegaly, enlargement of the arms or legs, and hardening of the skull and jaw due to high growth hormone
But very rarely, pituitary tumors are inherited.
Sometimes when these tumors are inherited, they appear along with other types of tumors as part of an inherited genetic syndrome (see next section).
Sometimes, however, only pituitary tumors occur. Researchers have discovered that some of these are caused by genetic changes in a person’s genes. (See What Causes Pituitary Tumors?)
However, more often, the cause of hereditary pituitary tumors is unknown.
Pituitary tumors are a component of the syndrome that increases the risk of other types of tumors. These syndromes are caused by abnormal changes (mutations) in a person’s genes. Among them are:
Multiple endocrine neoplasias, type I (MEN1): This is an inherited condition in which people are at risk of developing tumors of 3 glands: pituitary, parathyroid, and pancreas. It is caused by changes in the MEN1 gene and reaches half of the children of affected parents. If MEN1 syndrome affects your family, you should talk to your doctor about testing for this condition.
Multiple endocrine neoplasias, type IV (MEN4): This rare syndrome carries the risk of pituitary tumors and some other growths. MEN4 is caused by inherited mutations in a gene called CDKN1B.
McCain-Albright syndrome: This syndrome is caused by a mutation in a gene called GNAS1, which is inherited but occurs before birth. People with this syndrome have brown spots on their skin (called caffeine – light spots) and they develop many bone problems. They also have hormonal problems and pituitary tumors.
Carney complex: This is a rare syndrome in which people have heart, skin, and adrenal problems. They are also at risk of developing a wide variety of growths, including pituitary tumors. Most cases are caused by inherited changes in the PRKAR1A gene, but they have yet to be identified due to mutations in some other genes.
Diagnosis of pituitary tumors
NYU Longone endocrinologists are experienced in diagnosing pea-sized tumors of the pituitary gland at the base of the brain. This gland releases hormones that control many other glands in the body.
Functional pituitary tumors or adenomas produce high levels of hormones that cause a person to develop certain hormonal conditions. These can cause a variety of symptoms, depending on the hormones affected. An unborn premenopausal woman may produce breast milk or have irregular or abnormal ejaculation, and the man may have sexual problems. People may experience bone and soft tissue growth, high blood pressure, weight gain, and the presence of fat deposits on the face, upper back, shoulders, and midsection.
Dysfunctional pituitary tumors do not cause an increase in hormone levels. However, functional and dysfunctional tumors can grow large enough to cause headaches and vision problems. Larger tumors can also press on the pituitary gland and disrupt its ability to secrete hormones, causing hormone levels to drop.
These usually appear suddenly for no apparent reason. However, people with rare genetic defects called multiple endocrine neoplasia syndromes or familial pituitary tumor syndromes are at increased risk of developing functional and dysfunctional tumors. This risk may be higher in people with a history of radiation exposure.
To diagnose these tumors, endocrinologists will perform a physical exam. They will ask you about current or past health conditions and any symptoms you may have. Our experts can perform one or more of the following tests. Asymptomatic pituitary tumors are sometimes found during imaging tests for other conditions.
If a person has stretched their arms and legs, a doctor can perform a blood test to check for elevated levels of growth hormone. Some pituitary tumors produce elevated growth hormones in adults, causing a condition called acromegaly. In this disorder, growth hormone is referred to by the liver to make another hormone that “tells” the body’s tissues to grow, called insulin-like growth factor-1 (IGF-1). A blood test reveals high levels of this hormone.
To make a diagnosis of acromegaly, doctors can perform a glucose tolerance test. Blood is drawn before and after drinking a solution that contains glucose (sugar) so that doctors can measure glucose and growth hormone levels. In those without acromegaly, high blood glucose levels generally stop the body from producing growth hormones.
Cushing’s disease caused by a pituitary tumor can also be diagnosed by a doctor. With this condition, the pituitary adenoma produces too much adrenocorticotropic hormone, or ACTH, which signals the adrenal gland for large amounts of cortisol, a hormone that generally helps control stress. Blood, saliva, and urine tests can be used to detect high cortisol levels. Also, a doctor can measure blood levels of ACTH.
Doctors may also order blood tests for hypopituitarism, which may include low levels of one or more hormones released by the pituitary. This condition occurs when the tumor grows too large and interferes with the normal function of the pituitary gland.
Treatment of pituitary tumors
Most pituitary tumors do not require treatment. Treatment for those who do depends on the type of tumor, its size, and how much it has grown in their brain. Your age and your overall health are also factors.
Treatment involves a team of medical professionals, possibly a neurosurgeon (neurosurgeon), an endocrine systems specialist (endocrinologist), and a radiation oncologist. Doctors often use surgery, radiation therapy, and actions alone or in combination to treat pituitary tumors and restore hormone production to normal levels.
Transsphenoidal transnasal surgery
Open the Transhenoidal Transnasal Endoscopic Surgery pop-up dialog
If the tumor presses on the optic nerve or if the tumor overproduces certain hormones, the pituitary tumor may need to be surgically removed. The success of the surgery depends on the type of tumor, its location, its size, and whether the tumor has invaded the surrounding tissues. There are two main surgical methods for treating pituitary tumors:
Transsphenoidal transnasal endoscopic procedure. This usually allows your doctor to remove the tumor through the nose and sinuses without external incisions. Other parts of his brain are not affected and there is no visible scar. Large tumors are difficult to remove in this way, especially if the tumor attacks nearby nerves or brain tissue.
Transcranial procedure (craniotomy). The tumor is removed through the top of the skull through an incision in the scalp. Larger or more complex tumors are easier to reach with this approach.