Pituitary Tumors

What are pituitary tumors?

The pituitary gland is a small, pea-sized organ in the brain behind the back of the nose. The pituitary gland produces hormones that affect many other glands in the body. Although rare, most pituitary tumors are noncancerous (benign), comprising only 10 percent of brain tumors. However, because of the location of the pituitary gland, at the base of the skull, a pituitary tumor grows upward. And, eventually, most pituitary tumors press against the optic nerves, causing vision problems.

What are symptoms of pituitary tumors?

Symptoms vary depending upon what type of tumor is growing and what area of the pituitary gland is affected. Pituitary tumors can cause symptoms that are caused by excess production of pituitary hormones and symptoms caused by reduced production of pituitary hormones. Each individual also experiences symptoms differently, and the symptoms many resemble other conditions or medical problems. Always consult your physician for a diagnosis.

Causes and types of tumors:

Researchers do not know at this time what causes pituitary tumors. However, research studies show that having a hereditary condition, multiple endocrine neoplasia, type I (MEN 1), increases the risk of developing pituitary tumors, thyroid tumors, and pancreatic tumors. Multiple endocrine neoplasia, type I (MEN 1) has been shown to be responsible for about all inherited (those that run in families) pituitary tumors, but only 3 percent of all pituitary tumors.

The most common type of pituitary tumor is called an endocrine inactive tumor, which destroys some of the hormone-producing cells in the pituitary. An endocrine inactive tumor causes hypopituitarism, or an underactive pituitary gland, which may lead to failure of sexual function, reduced sperm production, and cessation of a woman's menstrual period.

Another common pituitary tumor is called a prolactinoma, a benign tumor that produces the prolactin hormone. Prolactin stimulates breast milk production after childbirth. According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), autopsy studies indicate that 25 percent of the US population have small pituitary tumors. Forty percent of these pituitary tumors produce prolactin, but most are not considered clinically significant. Clinically significant pituitary tumors affect the health of approximately 14 out of 100,000 people.

Other types of tumors act on other parts of the pituitary, with varying effects.

How are pituitary tumors diagnosed?

In addition to a complete medical history and medical examination, diagnostic procedures for pituitary tumors may include:

• blood and urine tests (to measure hormone levels)
  
  
• computed tomography scan (Also called a CT or CAT scan.) - a diagnostic imaging procedure that uses a combination of x-rays and computer technology to produce cross-sectional images (often called slices), both horizontally and vertically, of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat, and organs. CT scans are more detailed than general x-rays.
  
  
• magnetic resonance imaging (MRI) - a diagnostic procedure that uses a combination of large magnets, radiofrequencies, and a computer to produce detailed images of organs and structures within the body.
  
  
• biopsy - a procedure in which tissue samples are removed (with a needle or during surgery) from the body for examination under a microscope; to determine if cancer or other abnormal cells are present.

Treatment for pituitary tumors:

• your age, overall health, and medical history
• extent of the disease
• your tolerance for specific medications, procedures, or therapies
• expectations for the course of the disease
• your opinion or preference

• surgical removal of the tumor
  
  
• external radiation (external beam therapy) - a treatment that precisely sends high levels of radiation directly to the cancer cells. The machine is controlled by the radiation therapist. Since radiation is used to kill cancer cells and to shrink tumors, special shields may be used to protect the tissue surrounding the treatment area. Radiation treatments are painless and usually last a few minutes.
  
  
• stereotactic radiation therapy - a new radiation therapy that uses a single high dose of radiation sent directly into the cancerous tissue with very narrow beams of radiation. This is a precise technique that targets the cancer tumor, causing less damage to the surrounding tissues. An example of stereotactic radiation is called “gamma knife”.
  
  
• medications - to control the growth-hormone production by the tumor (i.e., bromocriptine - a drug which acts on hormone-producing tumors to suppress its hormone-producing function).

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