What is a pituitary adenoma?

Pituitary adenomas are benign tumors that arise from the pituitary gland. Pituitary tumors are rarely malignant. They are common tumors that arise from the pituitary gland located at the base of the brain. If they grow large enough, they can compress the optic nerves causing serious vision problems. Small pituitary tumors are known as microadenomas. Larger pituitary tumors are called macroadenomas.

Some pituitary tumors produce excessive amounts of hormones that can disrupt the body's metabolism. The most common type of hormonally active pituitary tumor is the prolactinoma. Excess prolactin in the blood may lead to irregular or absent menstrual periods in women (amenorrhea), decreased libido (sex drive) and erectile dysfunction (ED) in men. In addition, prolactinomas can cause infertility or inappropriate milk production by the breast in both men and women. A number of medicines are available to treat this disorder so that surgery is needed only infrequently. Most patients with prolactinomas are treated by endocrinologists, who are medical specialists, rather than neurosurgeons. However, surgery is still used to treat large tumors that threaten vision and in patients who do not tolerate medical therapy.

Other hormone-producing pituitary tumors include those that cause Cushing's Disease and acromegaly. Too much adrenocorticotropic hormone (ACTH) leads to overproduction of cortisol by the adrenal glands, giving rise to a disorder called Cushing's Disease. This leads to a particular kind of obesity, high blood pressure and many other problems. Surgical removal of these tumors can restore normal hormone production in many cases and relieve the adverse effects of the excess cortisol. Acromegaly results from excessive production of growth hormone by a pituitary tumor and is associated with coarsening of facial features, thickening of the soft tissues of the face, hands and feet, high blood pressure, diabetes mellitus and excessive sweating.

Also, pituitary tumors compress the normal pituitary gland and can adversely affect its function. Some pituitary tumors can be treated medically with drugs like bromocryptine and octreotide. Others must be treated surgically. For some patients, conventional radiation therapy and gamma knife (radiosurgery) can be used effectively as well.

Regardless of hormone production, all pituitary tumors can cause problems due to their size and location. This is because they can compress both the normal pituitary gland and the surrounding structures. Just as the tumor can produce an excess of a single pituitary hormone, a deficiency of the other pituitary hormones can arise as a result of compression of the normal pituitary gland by the tumor. Pituitary tumors can also cause vision problems by growing upwards against the optic nerves, which are essential for vision. Surgery to remove such tumors can relieve the pressure on the optic nerves and protect the patient's vision.

Pituitary Adenoma

These are common tumors that arise from the pituitary gland located at the base of the brain. If they grow large enough, they can compress the optic nerves causing serious vision problems. Such tumors are called macroadenomas.


Smaller tumors are known as microadenomas. Some pituitary tumors produce excessive amounts of hormones that can disrupt the body's metabolism. Pituitary tumors compress the normal pituitary gland and can adversely affect its function. Some pituitary tumors can be treated medically with drugs like bromocryptine and octreotide. Others must be treated surgically. For some patients, conventional radiation therapy and gamma knife (radiosurgery) can be used effectively as well.

Craniopharyngioma

This tumor grows at the base of the brain and arises from the band of tissue that connects the part of the brain known as the hypothalamus to the pituitary gland. They can grow to a large size and disrupt hormonal function and cause severe impairment of vision and other neurological functions. Craniopharyngiomas occur in both adults and in children and generally consist of solid tumor tissue and a fluid-filled tumor cyst. Treatment usually involves microneurosurgery; however, radiation therapy and gamma knife (radiosurgery) may be used in some cases as well.