The vast majority of pituitary tumors are benign (non-cancerous), but can be difficult to treat and cause a wide range of serious health problems.
It is estimated that as many as one in every five people worldwide has a pituitary tumor, but many remain undiagnosed, either causing no symptoms or causing “non-specific” symptoms resulting from hormonal abnormalities. Pituitary tumors tend to grow slowly, rarely spreading to other areas; these tumors can go undetected until they begin to press against the pituitary gland or other critical structures.
The pituitary is a pea-size gland surrounded by bone that is situated behind the nose at the base of the cranium (skull). Its location makes the gland and related structures difficult to reach surgically.
The pituitary gland is a major component of the endocrine system, which produces and regulates hormones – chemicals that influence organs and basic body functions. The pituitary gland is often referred to as the body’s master gland; it secretes hormones into the bloodstream that control other hormone-secreting glands in the body.
Actually, the pituitary is controlled by the hypothalamus, a small structure on the underside of the brain that serves as the control center to monitor and regulate a body’s basic functions. One way it does this is by controlling release of hormones from the pituitary into the bloodstream. A fluctuation in the delicate balance of hormones can have a cascading effect throughout the body.
The pituitary consists of two major parts: a larger front (anterior) lobe and a smaller back (posterior) lobe, which is connected to the hypothalamus at the pituitary stalk, or infundibulum. The hypothalamus communicates with the posterior pituitary through nerve fibers extending through the pituitary stalk to produce two hormones:
Oxytocin causes the uterus to contract during childbirth and stimulates milk ducts in the breasts.
Vasopressin, or antidiuretic hormone (ADH) regulates water retention in the kidneys.
The hypothalamus communicates with the anterior lobe through the release of certain hormones into a network of small blood vessels. These hypothalamic hormones control the release of hormones produced in the anterior lobe, which include:
Adrenocorticotropic hormone (ACTH) stimulates the adrenal glands to produce a hormone called cortisol. Cortisol plays a key role in response to stress and has widespread effects on numerous body systems.
Growth hormone (GH) stimulates growth and cell reproduction. In excess, growth hormone can cause gigantism if it begins in childhood, or a condition called acromegaly with adult onset. Growth hormone deficiency in childhood may cause short stature and other problems, such as delayed onset of puberty, while adults with a deficiency may develop obesity, loss of muscle mass and decrease in energy.
Prolactin stimulates the mammary glands to produce milk.
Luteinizing hormone (LH) and follicle-stimulating hormone (FSH) influence a variety of reproductive processes.
Thyroid stimulating hormone (TSH) stimulates the thyroid gland and affects temperature tolerance, energy, body weight, bowel regularity, and skin health.
Common Pituitary Tumors
A few rare hereditary disorders, such as multiple endocrine neoplasia type 1 (MEN1) syndrome, Carney complex, and familial acromegaly, may increase risk, but most pituitary tumors occur for reasons not yet known. Common tumors or disorders found in the pituitary region include:
Typically benign tumors, adenomas often press on the pituitary gland, causing loss of function of one or more hormones. Many pituitary adenomas are called “functioning tumors” because they actually make hormones and may cause an increase in hormone levels instead of a decrease.
Usually benign, these tumors can still be challenging. Craniopharyngiomas are often located above the pituitary gland or next to the pituitary stalk, the structure at the back of the gland that connects to the hypothalamus. It is not uncommon for craniopharyngiomas to grow to a large size before being detected.
Rathke’s cleft cysts are benign growths filled with fluid and found in an indentation (Rathke’s cleft) between the front and back lobe of the pituitary gland. Rathke’s cleft cysts do not make hormones and frequently exist without causing symptoms.
At Cedar's Sinai Medical Center, many medical and surgical specialists work together to plan, coordinate and carry out a treatment approach to address the unique challenges that a pituitary tumor presents. In addition to choosing the best option for treating the tumor itself, this multidisciplinary team, which includes experts from Cedars-Sinai’s Pituitary Center, works to restore balance to hormones that may have been out of control for years, while treating serious conditions caused by irregular hormones. Among the leading programs of its kind, the Pituitary Center conducts research and clinical trials to develop new treatments for patients suffering from endocrine disorders.
Surgical approaches for pituitary tumors have evolved substantially since the introduction of the endoscope for surgery inside the skull. The endoscope consists of a camera lens at the tip of a long tube, which is inserted through a nostril to enter the skull base via the sphenoid sinus, located deep within the cranium below the pituitary gland. This “endoscopic transsphenoidal approach” is available only at a few specialized pituitary centers in the nation.
A decade ago, neurosurgeons removing pituitary tumors typically used a large, bulky surgical microscope and entered through an incision under the lip, causing significant damage to nasal structures. But the nostril is a very narrow corridor, and the microscope is a large, fixed instrument that requires the surgeon to work at a greater distance. The surgical microscope is still used, but today, some surgeons utilize an endoscope for a nasal approach to tumor removal.
The endoscope is more maneuverable, fits within the nostril and provides the surgeon a panoramic view of the surgical site. The endoscopic procedure leaves no visible scars and because there is so little tissue destruction, the nose rarely needs to be packed to prevent post-surgical bleeding.
Open brain surgery (craniotomy) is still needed in some instances, when a tumor is located in a position that is not accessible endoscopically; but many operations that once could be performed only with open surgery can now be accomplished in a minimally invasive procedure.
In some cases, surgery will be followed by focused radiation therapy, which may be referred to as radiosurgery or radiotherapy.
Although terminology sometimes overlaps, radiosurgery is accomplished with a single, high dose of radiation, while radiotherapy usually consists of “fractionated” treatments delivered in smaller doses over a period of days or weeks. The goal of either approach is to bombard the tumor with a destructive dose of radiation while minimizing damage to healthy tissue.
Cedars-Sinai’s treatment teams have several advanced options for focused radiation treatment. For tumors within the cranium, the Gamma Knife® is an extremely precise system that uses up to 201 separate beams of radiation converging at a single point.
A Leading Center for Treatment of Brain and Cranial Base Tumors
With state-of-the art technology and facilities, Cedars-Sinai’s Brain Tumor Center is among the nation’s top referral centers. We emphasize patient-centered collaboration among physicians and surgeons from a wide variety of specialty fields, and the experience and expertise of neurosurgeons specializing in complex and challenging tumor-removal surgery.
Basic scientific research conducted at the Maxine Dunitz Neurosurgical Institute is translated into clinical trials at the Johnnie L. Cochran, Jr. Brain Tumor Center.
Cedars-Sinai is ranked among the nation’s leaders for Neurology and Neurosurgical services in U.S. News and World Report’s annual list of America’s Best Hospitals. For more than 20 years, Los Angeles area residents have named Cedars-Sinai the “most preferred hospital for all health needs,” according to National Research Corporation’s annual Healthcare Market Guide survey.