Brain Tumor and Spinal Tumor Program

Pituitary Adenoma

For more information, please visit our Comprehensive Brain & Spinal Tumor site or the Multidisciplinary Neuroendocrine Program

Information

Most pituitary tumors can be cured or controlled with appropriate treatment. There are different types of treatments, utilized depending on your tumor type and symptoms.

Treatment options include:
  • Observation over a period of time to see if treatment is needed
  • Medications
  • Surgery
  • Radiation therapy

The most common surgical procedure is performed through the nose called a transsphenoidal operation.

Observation without treatment

Some pituitary tumors may be observed without treatment because they grow very slowly. This may also be recommended if other medical conditions seriously increase the risk of surgical or other treatments. Because pituitary tumors are slow growing, patients can often be observed without treatment for long periods of time without the tumor causing serious problems. This is often the recommended form of treatment for patients who are age 75 or older (however, there is no specific age limit for pituitary surgery) or who have a serious medical illness such as heart disease. If a decision is made to observe the tumor without treatment, you may need continued hormone testing coordinated by our Neuroendocrine clinic, and you may need periodic visual testing with an ophthalmologist. CT or MRI scans are performed three to six months after initial diagnosis and every six to 12 months thereafter until the situation has been clarified. This period of observation without treatment provides information which helps the doctors decide if it is necessary to use other treatments which carry more risk.

Treatment with drugs

One type of pituitary tumor in particular, prolactinomas, can be successfully treated with drugs. Prolactinomas secrete a hormone called prolactin and can often be controlled by a drug called bromocriptine or a newer medication called cabergoline. These drugs often cause a reduction in the tumor size and at the same time decrease the abnormally high level of prolactin in the blood. Although bromocriptine or cabergoline may control the tumor and bring the levels of prolactin in the blood back to normal, they most likely will not make the tumor disappear unless the tumor is very small. Treatment with these drugs often must be continued for many years or indefinitely.

In most cases, bromocriptine is an effective treatment for prolactin secreting tumors and has few side effects. However, some patients taking bromocriptine develop nausea, headache, dizziness and weakness. Usually these symptoms can be avoided by taking small doses of the drug at first and slowly increasing the dosage up to the needed level over a period of several weeks or months. Side effects are similar with cabergoline but less common. Bromocriptine and cabergoline will not control all prolactin secreting tumors, and approximately 20 percent of patients with prolactinomas may need surgery or radiation therapy.

There are other drugs that may aid in the control of tumors that produce excess growth hormone. These drugs are used only if surgery and/or radiation therapy fail to cure the tumor, or during the period while the patient is waiting for radiation therapy to take effect. However, if a patient cannot have surgery, drugs can sometimes be an effective alternative treatment.

Radiation Therapy

Another treatment option for pituitary tumors is radiation therapy, which is most commonly used after surgery. Most people think of radiation therapy as a treatment for malignant tumors (cancer) but pituitary tumors (which are NOT cancerous) also respond well to radiation treatment. Some tumors have roots in the bone or coverings around the brain that involve vital nerves or blood vessels in such a way that surgical removal would cause significant damage to these important structures. In these cases, it is best to treat the main part of the tumor with surgery and to use radiation therapy for the roots or remaining tumor.

Radiation therapy, given under the direction of a radiation oncologist, is most effective after surgery has reduced the size of the tumor. The smaller the tumor is at the time of radiation therapy, the more effective the treatment is. Radiation usually requires a series of treatments that last a few minutes each day for four to six weeks. In most cases, the treatment is painless and is done on an outpatient basis. Radiation treatments generally begin a few weeks or months after surgery to allow time for incisions from the surgery to heal.

The ability of the gland to produce hormones often decreases slowly after radiation therapy. Twenty percent of patients who have normal pituitary function soon after the radiation therapy ends will require hormone replacement after two years. This figure rises to 50 percent after five years.

A specialized form of radiation therapy called radiosurgery can be used in selected cases. Radiosurgery involves a single, highly focused radiation treatment. The patient often can return home after the single treatment, which is done on an outpatient basis. Which form of radiation treatment (fractionated radiotherapy or radiosurgery) depends on recommendations of the neurosurgeon and the radiation oncologist.

Surgery

Surgery is the preferred treatment for most pituitary tumors. Two types of surgeries are offered for pituitary tumor removal.

Transsphenoidal Surgery

Most pituitary tumors are removed by the transsphenoidal method of surgery, directed through the nose to the bottom of your skull where the pituitary gland is located.. In the past, transsphenoidal surgery was started by making a one to-two inch incision under your lip at the top of your upper gum or within the front part of the nose.

In recent years, the surgery has been modified so that there is no need for an incision under the lip or in the front part of the nose. The new procedure is called an endonasal procedure because the tumor is approached through the nasal cavity without an incision.

The tumor is reached by working through one nostril and making a hole in the back of the nose into the bottom of the skull. Through this hole, the surgeon can see the bottom of the pituitary gland and the tumor, and can thus remove the tumor. The endonasal procedure reduces operating room time by as much as two hours, reduces the discomfort associated with the surgery, and allows for a quicker recovery compared to the older techniques. In fact, most patients now go home the next day or the day after that.

Often, the surgeon will remove a small piece of fat from just below the skin on the abdomen to fill the cavity created by the tumor removal. The bottom of the skull is sometimes reconstructed using an absorbable man-made mesh. This will help bolster the strength of the repair of the hole made in the bottom of the skull, and helps prevent leakage of cerebrospinal fluid (CSF). The CSF fluid surrounds the brain, spinal cord, and pituitary gland and acts as a cushion, and provides nutrients to the nervous system.

In a small number of patients, the fat or muscle packing will not hold and CSF may leak from the nose. If the drainage continues, it may allow bacteria into the CSF and may result in an infection called meningitis. Sometimes waiting a few days, or treatment with a small drainage tube in the lower back, will allow this drainage to stop so that no further treatment is needed. However, in a few patients (less than 2%), another procedure may be necessary to seal the hole at the bottom of the skull.

What is the pituitary gland?

The pituitary gland, located at the base of the brain, is a small organ about the size of an acorn. It is surrounded by a bony saddle like structure called the sella turcica, which resides above the sinuses at the back of the nose. The pituitary gland is sometimes referred to as the "master gland" because it releases substances that control the basic functions of growth, metabolism, and reproduction, including substances that change the activity level of the thyroid and adrenal glands, the testicles in the male, and the ovaries in the female.

The pituitary gland is divided into two parts, called lobes. These are referred to as the anterior (front) and the posterior (back) lobes. Each lobe releases hormones, which control basic activities within the body. The specific hormones and their activities are shown in this table.

ANTERIOR LOBE HORMONES FUNCTIONS
Thyroid Stimulating Hormone (TSH) Causes the thyroid gland to grow and releases thyroid hormones (called T4 & T3)
Adrenocorticotrophic Hormone (ACTH) Causes the adrenal gland to release several hormones; the major one is cortisol
Growth Hormone (GH) The main hormone for general body growth (in children) and body composition (in adults)
Follicle Stimulating Hormone (FSH) Stimulates ovulation in women and the production of sperm in men
Luteinizing Hormone (LH) Stimulates ovulation in women and testosterone production in men
Prolactin (prl) Responsible for breast milk production in women
POSTERIOR LOBE HORMONES
Antidiuretic Hormone (ADH) Controls thirst and the amount of water released into the urine
Oxytocin Stimulates uterine contractions in women

Pituitary tumors are almost always benign. It is rare for them to ever become malignant.

Understanding Your Symptoms

A tumor in the pituitary gland causes symptoms by either stimulating the gland to release too many hormones or by pressing on the gland, causing it to release too few, symptoms often determined by the type of tumor.

A pituitary tumor can cause an increase in any of the anterior pituitary hormones listed in the table. Examples include:

  • An increase in the amount of growth hormone (GH) causes the body to grow at an abnormally fast rate. Bones become thicker, the hands and feet may appear wider or thicker and the jaw may protrude. This condition is called acromegaly.
  • If a tumor releases adrenocorticotrophic hormone (ACTH), it causes the adrenal glands to secrete too much cortisol; this leads to fat deposits, especially in the shoulders, face, and abdomen. It can also cause diabetes, osteoporosis, abnormal hair growth (especially in women), and stretch marks called striae. This condition is called Cushing's disease.
  • Elevated levels of prolactin may cause secretion of breast fluids in women and decreased sexual drive in men and women. It also may cause irregular or absent menstrual periods in women, and difficulty in having an erection in men.

Because the pituitary gland is located within the skull, when a tumor becomes large it may cause headaches that worsen as it grows. Also, since the pituitary gland is located near the nerves that connect the eyes to the brain, a pituitary tumor can press on the nerves and cause vision loss. Loss of peripheral vision may occur first and be undetectable, but it may progress to eventual blindness if the pressure is not removed from the nerve. The tumor may also press on the nerves that move the eye and cause double vision. If the tumor is very large, it may press on other parts of the brain and cause problems with memory, weakness or numbness.


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Condition Facts

  • May cause excessive secretion of hormones
  • Accounts for 6% of all brain tumor
  • Common symptoms: headache, depression, visual loss, nausea or vomiting, behavioral or cognitive changes, cessation of menstrual period, leaking of fluid from breasts, hair growth in women, impotence in men, abnormal growth of hand and feet, abnormal weight gain