Most pituitary tumors are pituitary adenomas: benign, slow-growing tumors that arise from cells in the pituitary gland. The pituitary gland is located at the base of the brain, just behind the eyes. The pituitary gland is considered to be the master hormone gland that regulates the body's hormones.
Our comprehensive approach to diagnosis and treatment of pituitary conditions sets the UCLA Pituitary Tumor Program apart. Our physicians treat a high volume of patients every year and perform over 100 pituitary surgeries a year, making us one of the top programs in the United States.
Learn more about pituitary adenomas:
The pituitary gland has different types of pituitary cells, each producing special hormones released into the bloodstream that affect other organs in the body.
Pituitary tumors originate from one of these specialized cells. If the tumor cells produce an excess of one or more hormones, it is called a "functional" adenoma. Examples of functional adenomas include:
Pituitary tumors that do not secrete active hormones are called clinically nonfunctioning adenomas.
Pituitary adenomas are relatively common. Tiny, microscopic pituitary adenomas are found in one in five adults. However, most of these tumors never grow or cause problems. Often, a patient is undergoing a magnetic resonance imaging (MRI) scan of the brain for another reason, and the doctor discovers a pituitary adenoma.
Pituitary adenomas are classified in several different ways depending upon their properties:
Most pituitary adenomas occur spontaneously, meaning they are not inherited.
There are cases of familial pituitary tumors, which is an inherited tendency to develop pituitary adenomas. However, these cases are uncommon. In many familial cases gigantism or a young onset of acromegaly is more common.
Multiple endocrine neoplasia type 1 (MEN 1) is a rare condition characterized by simultaneous tumors of the pituitary, pancreas and parathyroid glands. Pituitary adenomas develop in 25 percent of patients with MEN 1.
The symptoms that pituitary adenomas produce depend upon several factors, including whether the tumors are hormone-producing or clinically nonfunctioning.
Hormone-producing pituitary tumors can also grow to large sizes, causing the same problems described above in addition to the hormone-related effects.
When the tumor compresses the normal pituitary gland, it can cause it to fail leading to pituitary insufficiency (hypopituitarism). The symptoms will depend upon which hormone is involved.
Pituitary adenomas can suddenly bleed internally (hemorrhage), leading to an abrupt increase in size. In other cases, the tumor can outgrow its blood supply, leading to swelling of the dead tissue. These scenarios are termed "pituitary apoplexy."
Patients with pituitary apoplexy generally experience a sudden headache. If accompanied by acute vision loss, this is a surgical emergency. Pituitary apoplexy can also lead to severe pituitary insufficiency, the symptoms of which can occur days to weeks later.
A pituitary adenoma may be suspected based on symptoms, the medical history, and physical findings. Explaining your symptoms is a crucial part of diagnosis, as your doctor uses the information to determine whether a pituitary tumor is secreting an excess of hormones and if there is evidence of pituitary insufficiency.
Standard diagnostic tests include:
Hormone testing can detect or confirm a functional adenoma, as well as determine if there is evidence of pituitary insufficiency. Some functional tumors, particularly prolactinomas, can effectively be treated without surgery and therefore it is very important that comprehensive hormone testing be performed prior to the consideration of surgical removal of the tumor. An endocrinologist who specializes in pituitary tumors will help interpret the results of the test.
One method we use to detect pituitary adenomas is a magnetic resonance imaging (MRI) scan. An MRI can reliably detect adenomas larger than four millimeters. We use a special pituitary protocol to help obtain an accurate image. In some cases, a powerful 3T (Tesla) MRI scanner may detect even smaller tumors not visible during a regular MRI scan. MRI is the preferred imaging scan for detecting pituitary adenomas, though sometimes a computed tomography (CT) scan is used.
A neuroradiologist specializing in pituitary tumor imaging may help in finding very small tumors, particularly in Cushing's disease.
There are other tumors that produce symptoms similar to that of a pituitary adenoma. Your doctor will want to rule out these other tumors before confirming a diagnosis. Tumors that mimic the symptoms of a pituitary adenoma include:
Treating a pituitary adenoma depends on several factors, including:
Ideally, more than one specialist is involved in managing the treatment of pituitary adenomas. Our dedicated Pituitary Tumor Program includes specialists in many different fields, working together to ensure the best outcomes for you.
If you have a hormone-producing pituitary adenoma, it can sometimes be treated medically. An endocrinologist who specializes in hormone-producing tumors, called a neuro-endocrinologist, may be necessary in managing your care. He or she can also provide enrollment in clinical trials if standard treatments are insufficient.
Medication can help certain pituitary tumors:
It is also important to address pituitary failure (hypopituitarism), especially prior to surgery. Inadequate cortisol or thyroid levels can be life threatening if they are not treated before surgery.
If the pituitary adenomas require surgery, typically the best procedure is through a nasal approach. Our neurosurgeons who specialize in pituitary tumor surgery are experts in the minimally invasive endoscopic endonasal technique. This procedure removes the tumor while minimizing complications, hospital time and discomfort. This advanced technique requires specialized training and equipment.
Very large tumors that extend into the brain cavity may require opening the skull (craniotomy) to access the tumor. Our surgeons are also experts in the minimally invasive "key-hole" craniotomy, utilizing a small incision hidden in the eyebrow.
Some tumors cannot be removed surgically and may not respond to medications. Radiation therapy can be effective in controlling the growth of these tumors.
We use an advanced method of radiation therapy called stereotactic radiosurgery. This is a carefully sculpted radiation beam that delivers a high dose of radiation to the tumor target; the surrounding brain structures receive only a fraction of the radiation. The healthy structures are typically unharmed, with the exception of the pituitary gland.
A consequence of radiation treatment is that it can cause delayed pituitary failure. This typically occurs several years after treatment. If this happens, you will require hormone replacement.
The UCLA Pituitary Program offers numerous clinical trials, testing new therapies for pituitary adenomas.
To schedule an appointment with one of our physicians at the Pituitary Tumor Program, please call (310) 825 5111.
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