Malin Dollinger, MD, Ernest H. Rosenbaum, MD, and Orlo H. Clark, MD
Adapted for the Canadian edition by Richard Hasselback, MD
Tumors in the pituitary gland, which is located at the base of the brain ( see Areas in the brain ), are benign (adenomas) and curable over 90 percent of the time. But these tumors can become large enough to damage nearby nerves and brain tissue , sometimes permanently. By pressing on the nerves to the eyes, a pituitary tumor can cause progressive vision loss and even blindness. In some cases, the tumor compresses the pituitary gland, preventing it from producing the normal amount of hormones . Hypothyroidism, adrenal insufficiency and a deficiency in growth hormone can result.
Types Many pituitary adenomas produce excess hormones, causing significant symptoms. The increased production of growth hormone can produce a disease called acromegaly. Excess prolactin can cause impotence in men and the loss of menstrual periods and breast secretion in women. Excess ACTH (adrenocorticotropic hormone) can result in Cushing's disease. Some tumors, such as chromophobe adenomas, are non-functional but may lead to hormone deficiency by compressing the normal pituitary.
