What is a Pituitary Tumor?
The pituitary is one of the most important glands in the body. It is attached to the base of the brain. Its function is to control the secretion of hormones; therefore, it is known as the "master gland." It affects growth, metabolism, sex drive, and stress functions. Pituitary tumors are abnormal growths of cells within the pituitary gland.
Pituitary tumors are classified as one of three types: benign pituitary adenomas, invasive pituitary adenomas, and pituitary carcinomas. Benign pituitary adenomas are non-cancerous tumors that grow at extremely slow speeds, and do not spread to surrounding structures. Invasive pituitary adenomas are benign tumors that grow and affect the bones of the skull or sinus cavities. Pituitary carcinomas are cancerous tumors that can grow and affect the brain, spinal cord and areas outside the central nervous system, or CNS.
These tumors can affect the pituitary gland's functions. They can make it secrete either too many or too few hormones. As a result, abnormal hormone levels can cause problems in other areas of the body.
Causes of Pituitary Tumors
A tumor is an abnormal growth caused by abnormal cell multiplication that does not serve any physiological function. Cell division is regulated by the tumor suppressor genes. These genes also help to repair any damage caused to the DNA. Tumor suppressor genes are constantly at war against the cancer-causing genes called oncogenes. When tumor suppressor genes fail to function properly due to mutations that affect protein encoding, unregulated cell division and growth can occur and cause the development of a tumor.
The body's natural defense system should optimally detect the abnormal cells and kill them. But tumors may produce substances that obstruct the immune system from recognizing the abnormality of tumor cells and eventually the tumor cells may overpower all internal and external checks to their growth.
Certain types of radiation exposure and genetic disorders have been linked with tumor growth. Although some environmental factors are suspected of contributing to the development of tumors, doctors do not know many of the risk factors of many types of tumors yet.
Symptoms of Pituitary Tumors
The symptoms of pituitary tumors depend on whether they are functioning or non-functioning. Functioning tumors are those that produce hormones. A wide variety of symptoms are possible depending upon the hormone affected. Non-functioning tumors are those that do not produce hormones. Symptoms will be directly related to the tumor's size. These may include headaches, nausea, vomiting and vision problems.
Other symptoms of pituitary tumors may include:
- Production of breast milk (even in women who are not pregnant or nursing)
- Loss of male sex drive or lower sperm count
- Unexplained weight changes
- Bruising easily
- Aching joints and muscle weakness
Diagnosis of Pituitary Tumors
If a person is suspected of having a brain tumor, a neurological exam will be done. This involves checking the function of eyes, ears, nose, and muscles. Sensation, balance and coordination are also tested. Mental state and memory are also assessed, and the levels of hormones in the blood are examined.
Diagnostic imaging tests may be ordered, including computerized tomography, or CT, scans or magnetic resonance imaging, or MRI, scans. The results from these imaging studies can help to determine the size, location, and type of tumor. The diagnosis may also be confirmed by examining a tissue sample taken from the tumor in a procedure called a biopsy.
Treatment options may vary depending on the severity of the condition. Some pituitary tumors may be treated with medication, but observation of the tumor with regular MRI scans should be performed to ensure your safety. You may be referred to an endocrinologist if hormone changes occur or if you are prescribed hormone-blocking medication as a form of treatment.
If the pituitary tumor is large, aggressive or putting pressure on nearby structures, like the optic nerve, then surgery may be necessary. Radiation therapy may be used to complement surgery.