Q: Based on laboratory tests and X-rays, my doctor has told me that I have a pituitary tumor that is producing too much growth hormone. It is hard for me to believe this diagnosis when I am not even 6 feet tall while newspapers and magazines describe 8- and 9-foot giants with pituitary tumors.
A: Prior to puberty, when linear growth of the arms and legs is still possible, overproduction of growth hormone by one type of pituitary tumor can lead to extremely tall stature, sometimes called gigantism.
More often, such tumors occur in adults, who can no longer grow taller, and instead develop progressively enlarged hands, feet, head and jaw. Other indications of excessive growth hormone in adults include coarsening of facial features, thickening of the skin, painful arthritis involving the back and knees, increased sweating and body hair, numbness and tingling of the hands, hypertension and often diabetes. The changes in appearance usually come about so slowly that they may go unnoticed.
The diagnosis can be suspected when there is an increase in the glove, shoe or hat size or upon comparing old photographs with current appearance. In addition to these effects of overproduction of growth hormone, pressure from an expanding pituitary tumor can cause headaches, and impingement on the optic nerves, which cross close to the pituitary, can cause visual field defects.
Pituitary tumors often compress and destroy adjacent pituitary tissue and interfere with the production of hormones that ordinarily stimulate the thyroid, adrenal, ovaries and testes -- a condition called hypopituitarism.
Hypopituitarism is treated by replacement of the deficient thyroid or adrenal steroid hormone.
The diagnosis of a growth-hormone-producing pituitary tumor can be made by measuring an elevated blood level of growth hormone that does not fall to very low levels, as it does in normal individuals, after the ingestion of glucose.
The size of the tumor can be determined by a nuclear magnetic resonance scan. Pituitary tumors, which are rarely malignant, can be removed by surgery or treated by radiation or a combination of surgery and radiation.
Dr. Margolis is professor of medicine and biological chemistry at the Johns Hopkins School of Medicine.