Pituitary Tumors

Types

Pituitary tumors (adenomas) are almost always noncancerous (benign). The majority of pituitary tumors do not spread outside the skull and usually are confined to the pituitary gland or nearby brain tissues. However, pituitary tumors impact the function of other organs in the body because they can cause several glands to secrete hormones.

Nonfunctioning Pituitary Tumors

Noncancerous (benign), nonfunctioning pituitary tumors do not produce excess hormones as functioning tumors do. They typically grow slowly and cause few symptoms. When they spread outside the pituitary gland, nonfunctioning pituitary tumors can press on the nerves of the eye, causing vision problems and headaches. A nonfunctioning pituitary tumor also can press on the pituitary gland and stop its normal production of hormones.

Functioning Pituitary Tumors

Functioning tumors cause an overproduction of hormones. They include prolactin-producing hormones, adrenocorticotropic hormone-producing tumors, growth hormone-producing tumors and thyroid-stimulating hormone-producing tumors.

Adrenocorticotropic hormone-producing tumors

This type of pituitary tumor produces adrenocorticotropic hormone, which causes the adrenal glands to create the hormone cortisol. Cushing's syndrome develops when the adrenal glands produce too much cortisol. The syndrome causes weight gain, exaggerated facial roundness, skin thinning, a hump on the upper back, high blood pressure, muscle weakness, bruising and stretch marks.

Growth hormone-producing tumors

These tumors produce excess amounts of growth hormone. Overproduction of this hormone can cause coarsened facial features, enlarged hands and feet, excess sweating, high blood pressure and heart problems. It also can aggravate other medical conditions such as diabetes, heart disease and hypertension.

Prolactin-producing tumors

Excess secretion of prolactin by the body can cause a decrease in the levels of the hormone estrogen in women and the hormone testosterone in men. Women may stop experiencing menstrual periods, while men may have impotence and a decreased sex drive.

Thyroid-stimulating hormone-producing tumors

Thyroid-stimulating hormone causes the thyroid gland to excrete extra amounts of the hormone thyroxine. Overactive thyroid disease (hyperthyroidism) can occur as a result. Side effects of hyperthyroidism include increased metabolism, sudden weight loss, an irregular heartbeat, and irritability or nervousness.