Being diagnosed with a pituitary tumor is frightening, but with proper medical care, these tumors of the master gland are treatable and curable.
Jerry Croopnick had no idea there was anything wrong with his health until a routine eye exam turned up an unexplained loss of peripheral vision.
Then a subsequent magnetic resonance imaging (MRI) of his head determined the cause as a pituitary adenoma-a small growth on the pituitary gland just behind and between the eyes-and he started to worry.
"It's not a fun thing to hear that you have a tumor pushing on your brain. It was an extremely nervous time for me," says the 59-year-old Californian.
As frightening as it may sound, more than one person in five has a small pituitary tumor. Unlike Croopnick, however, most of those people live their entire lives without suffering any ill effect and, usually, never suspecting they have it.
Martin Weiss, M.D., chair of the Department of Neurological Surgery and holder of the Martin Weiss Chair in Neurological Surgery, says that only about 10,000 Americans a year suffer significant health problems as a result of pituitary tumors, but notes that, untreated, they can cause abnormal growth, facial deformities, loss of sex drive, blindness and a wide range of other health effects.
Fortunately, with proper diagnosis and medical care, fully 98 percent of all pituitary tumors are treatable and 92 percent of all pituitary tumors are curable.
That was the case for Croopnick, who underwent successful surgery and follow-up treatments at USC that restored his peripheral vision and excised the tumor.
Weiss says that in many respects Croopnick was lucky, because the tumor was accurately diagnosed fairly early.
"Problems of the pituitary just aren't that common. Some doctors go their entire careers without ever seeing one. And because problem pituitary tumors are so uncommon, they're not recognized enough by patients or their doctors," Weiss says. "Patients are often frustrated that it took so long to find a reason for their symptoms."
In fact, according to the Pituitary Network Association, it is not uncommon for a delay of several years between onset of symptoms and a correct diagnosis.
The pituitary, a peanut-shaped gland located at the base of the brain behind and between the eyes, secretes hormones that govern diverse and vital bodily functions such as growth, sexual development and urine output. Operating as a "master gland," it also regulates other important glands such as the thyroid, adrenals and gonads to ensure they are producing the proper amount of hormones.
The symptoms of pituitary tumors vary depending on the size and location of the tumor and whether or not the particular tumor secretes hormones. The majority of pituitary tumors-called adenomas-grow slowly within the pituitary gland and are generally classified according to their size and whether they secrete hormones. Microadenomas are less than 10 millimeters in diameter, while tumors larger than 10 millimeters are called macroadenomas.
Of hormonally active, or "functional," adenomas, about 50 percent secrete prolactin, which influence reproductive and sexual functions, 20 percent secrete human growth hormone and another 20 percent secrete hormones that stimulate the adrenal glands. The remainder of hormonally active tumors secrete multiple hormones.
The type and amount of hormones that a hormonally active tumor secretes can produce wide-ranging-and potentially life-threatening-effects:
o Prolactin-producing tumors, the most common pituitary adenoma, overload the body with a hormone that induces lactation. Most commonly occurring clinically in women of childbearing age, the tumor can interfere with menstruation or trigger inappropriate production of milk by the breasts. In men, prolactin-producing tumors may cause headaches, vision loss, impotence or a decreased sex drive.
o Growth hormone-producing tumors, more commonly found in men, can cause a painful chronic condition called acromegaly, in which bones grow out of control. The condition can cause facial deformities, enlargement of the hands, feet and head and numerous other symptoms such as hypertension, cardiac enlargement, diabetes, excessive sweating and mood disorders. When excessive secretion of growth hormone occurs in children before normal growth has been completed, growth hormone-producing tumors can cause gigantism, wherein the long bones of the body continue to grow past the normal stopping time, making them unusually tall. Delayed onset of puberty is also common.
o Adrenocorticotropic-producing pituitary tumors, more common in women than men, stimulate the adrenal glands, which in turn secretes glucocorticoids, or natural steroids. Excess glucocorticoids cause Cushing's disease, with symptoms including weight gain, muscle weakness, diabetes, menstrual irregularities, excessive hair growth, bruising and hypertension.
Although pituitary adenomas are an equal opportunity problem, affecting young and old, men and women, they tend to be more noticeable and consequently diagnosed earlier in women because such tumors frequently disrupt or stop menstruation.
Tumors that do not secrete hormones can still have dramatic impact on a person's health, Weiss notes. They can grow large enough to crowd out and kill normal pituitary cells that produce hormones that keep the body's metabolism in balance, a condition known as hypopituitarism. A broad constellation of symptoms resulting from hypopituitarism include: fatigue, weakness, sensitivity to cold, decreased appetite, weight loss, impotence, infertility, low blood pressure and headache.
Although the vast majority of pituitary adenomas are non-malignant-cancerous pituitary tumors are extremely rare-and grow slowly within the pituitary gland, more aggressive and invasive tumors do occur. As they grow out of control into other regions of the brain, they can cause blindness, increased pressure on the brain and eventually become life threatening, Weiss says.
The good news is that pituitary adenomas can be treated relatively easily with drugs, surgery, or radiation-individually or in combination. Peter Singer, M.D., professor of clinical medicine, says that physicians decide on the best approach after a thorough clinical examination, blood tests to determine hormone levels as well as MRI scans of the pituitary.
Surgery is the cornerstone of treatment for patients with pituitary tumors, although for some tumors that secrete hormones, specifically prolactinomas, medical therapy may be approved. Drugs such as bromocriptin or cabergoline block production of excess hormones and shrink the adenomas they target. Symptoms caused by the tumors may disappear within weeks after a drug regimen is started. Patients with growth hormone-secreting tumors and Cushing's disease are also best treated surgically, although the medication octreatide is sometimes necessary for individuals not cured surgically.
Singer recommends that younger patients with prolactinomas, especially women under 20, be treated with surgery rather than medication "because it's a very low-risk procedure in the hands of someone like Dr. Weiss and then when you're done with it, you're done with it."
Singer points out that the drugs must be taken indefinitely-often several times a day-and are not tolerated by everyone. For example, fully 40 percent of people with growth hormone-secreting tumors cannot be treated with octreatide because of side effects-although new drugs are being investigated that may block excess growth hormone circulating in the body from causing harm.
When surgery is indicated, it usually involves a transphenoidal operation, in which surgeons use small instruments to remove the tumor through an incision under the upper lip or through a nasal passage. Alternatively, for tumors that are large or difficult to reach, surgeons may elect to approach and remove them through the base of the skull.
A transphenoidal operation was the initial treatment that Croopnick underwent for his pituitary tumor in January 1998.
"I went in with some trepidation, which I think is natural any time you go in for brain surgery, but they emphasized how simple a procedure it was and that Dr. Weiss has done more of these than probably anybody. It went surprisingly well and I was in the hospital for three or four days and then back at work within two weeks," Croopnick says.
Because a portion of the tumor was encasing the carotid artery, the surgical team was unable to remove it entirely without risking injury to the carotid. Several months later, Croopnick returned for radiosurgery treatment that eradicated the remaining portion of the growth.
Michael L.J. Apuzzo, M.D., the Todd-Wells Professor in Neurosurgery, says that in radiosurgery, physicians use beams of radiation to treat tumors in a painless outpatient procedure.
Called stereotactic radiosurgery, the procedure, which does not cause hair loss or other side effects often associated with radiation therapies, shrinks the tumor over time and is often successful with tumors that are surgically inaccessible.
"It's important to stress that this is a very benign procedure-if a patient is a candidate for it, they're very fortunate," he says.
Apuzzo emphasizes that no one form of treatment is "best" because what works well for one patient may be futile for another: "We use a combined approach, relying on microsurgery and radiosurgery as just two arrows in the quiver" in attacking the source of pituitary problems.
When radiosurgery is needed, physicians at USC University Hospital use the model C Gamma Unit-which is one of only five such operating machines in the world and is the most advanced machine of its kind. It uses robotics to position the patient's head precisely and quickly to deliver radiation where it belongs-and nowhere else.
"The patients love it because they may come in at 11 a.m. for a 1 p.m. procedure and by 4 p.m. they're already home."
Still, Apuzzo notes that although state-of-the-art equipment is a great boon, USC's main advantage is the expertise and experience of its neurosurgery team.
"Twenty-eight years ago, we were among the first groups anywhere to introduce stereotactic neurosurgery and later to use CT and magnetic resonance imaging to create navigational maps to do precise surgeries. Our radiosurgery team has developed many of the groundbreaking methodologies that are now used elsewhere," Apuzzo says.
Croopnick says USC's expertise in treating pituitary tumors is well known in the national medical community and was, in fact, the primary reason he sought treatment here.
He adds that he never would have found USC unless he had been an active participant in his own health care and urges others who have potential health problems to educate themselves about their conditions and learn about the various kinds of treatments available.
"I tend to be very proactive when it comes to my health and I think that everyone should be aggressive in getting problems diagnosed and treated," he says. "It's always easier to treat a problem when it's small rather than when it's big."
For more information about neurological surgery at the Keck School of Medicine, or to learn more about The Doctors of USC, call 1-800-USC-CARE (1-800-872-2273) or visit www.usc.edu/go/usc-care.