The pituitary gland is a small oval gland at the base of the brain. It controls most of our hormones. These control thyroid activity, the monthly cycle in women, sex drive, growth in children, adrenal gland activity, urine output, the start childbirth and milk-production after pregnancy.
Doctors describe these tumors in several ways. One is as:
- Secreting, which release hormones. These can trigger symptoms such as impotence, stopping of a woman's monthly periods, galactorrhea, abnormal body growth, Cushing's syndrome or hyperthyroidism.
- Non-secreting, which are usually larger when found and treated with surgery and radiation therapy.
Another is by size:
- Microadenomas, which are smaller than one centimeter
- Macroadenomas, which are larger than one centimeter. These can be quite large if not found until they affect nearby brain tissues. The optic nerves are particularly vulnerable. Early on, the vision at the edges of the field of sight can be affected. Pituitary tumors can spread into the area of the head that contains the carotid artery and cranial nerves. When this occurs, the tumors may be particularly difficult to completely remove.
Symptoms vary based on the tumor's size, where it is and whether it secretes or not. They may include:
- Overproduction of hormones. Functional tumors, which secrete hormones, can produce too much hormones. Almost 20% secrete prolactin, a hormone that causes milk production in women. Very high levels can cause milk production in men and women who are not pregnant. Menstrual irregularities may also occur.
- Underproduction of hormones. Some 75% of pituitary tumors don't produce hormones. These can grow and damage normal gland tissue. This cuts hormone production. Often the first hormones affected are those that relate to sex. This can cause irregularity or loss of menstruation in women and sterility with loss of sex drive in men and women.
- Growth disorders. These cause excessive growth (gigantism) in children. In adults, they cause acromegaly, or abnormal growth of the face bones, enlarged hands and feet, excessive sweating and heart disease.
- Disturbances in vision will occur if the tumor presses on the optic nerves.
A magnetic resonance imaging (MRI) scan is the most sensitive test for pituitary tumors. It can rapidly show even small tumors. Sometimes computed tomography (CT) scanning is used. However, this may not detect small tumors.
Complete hormone testing is also important. An endocrinologist may need to be consulted. A complete neurological evaluation, including a visual field exam, is also needed to see if there is any visual loss.
Treatment is set by the size of the tumor and the patient's symptoms and hormone status. Reducing pressure on nearby structures (generally the optic nerves) and restoring normal hormone production is important.
Treatment may include:
- Observation and monitoring with MRI scans and visual field studies, if the patient's vision is not threatened and hormone production is normal
- Stereotactic radiosurgery
- Radiation therapy