A pituitary tumor is an abnormal growth of cells on the pituitary gland. This small, bean-shaped gland is located inside the skull, just below the brain and above the nasal passages. The pituitary gland connects directly to an area of the brain called the hypothalamus, providing a link to the body’s endocrine system which controls hormone production. Most pituitary tumors are benign; pituitary cancer is rare. However, even benign tumors may cause serious health problems due to their proximity to the brain and the sinuses. Many of these tumors produce excessive amounts of hormones. Pressure on nearby structures may cause headaches. A person may experience changes in vision because the optic nerve, which connects the eyes to the brain, passes very close to the pituitary gland.
Symptoms of pituitary tumors
Some pituitary tumors don’t cause symptoms. People may be unaware that they have a tumor. Small tumors may not put pressure on surrounding structures. They may not spread to other tissues and may not produce excess hormones. However, larger pituitary tumors, known as macroadenomas, may press on nearby structures or cause changes in hormone levels. Symptoms of a larger pituitary tumor may include some of the following:
- Vision loss, especially peripheral vision
- Overproduction of hormones
- Hormone deficiencies
- Sexual dysfunction
- Irregular menstrual periods
- Unintended weight loss or weight gain
- Cushing’s syndrome
- Thyroid disease
Hormones affected by pituitary tumors
Different symptoms are related to which of the body’s hormones are overproduced or deficient. The following are body functions that may be affected by the overproduction or lack of specific hormones.
- Growth hormone (somatotropin)- promotes body growth during childhood
- LH and FSH hormones- control ovulation in women and sperm production in men
- Prolactin- causes milk production in women
- Oxytocin- causes uterine contractions during childbirth
- Vasopressin- controls urination
- Thyroxine- controls the thyroid gland and the body’s metabolism
Who is at risk?
Individuals with a family history of multiple endocrine neoplasia, type 1, are at increased risk of developing pituitary tumors. In most cases, though, there is no known cause or family history of these types of tumors. Tumors are more common as people age.
Diagnosing pituitary tumors
Physicians may use a combination of tests to diagnose pituitary tumors. They may be diagnosed by a CT scan or an MRI of the brain. Blood and urine tests will determine whether there are excessive amounts or a lack of certain hormones. A vision test can help determine whether a tumor may be pressing on the optic nerve.
Treatment of pituitary tumors
Many pituitary tumors require no treatment. If the tumor is not causing symptoms, the physician may decide to watch and wait. Some factors to consider include the size of the tumor and how far it has gone into the brain. Medications can be used to bring hormone levels to normal and sometimes shrink the tumor. A neurosurgeon may remove the tumor if it is pressing on the optic nerve. A small tumor may be removed through the nasal passage and sinuses. Larger tumors may be removed through an incision in the upper part of the skull. Radiation therapy may also be used to destroy the tumor. Pituitary hormone replacement therapy may be necessary after surgery and radiation.