Functioning tumors of the adrenal gland are rare but incidentally discovered benign tumors involving the adrenal gland are discovered by CT scanning usually done for another purpose in 1.5 to 8 percent of patients.
The two glands, located just above each kidney ( see Kidney cancer ), produce a variety of hormones that are essential for life. The central part of the glandóthe medullaó produces norepinephrine (noradrenaline), a substance necessary for the transmission of nerve impulses, and epinephrine. The outer partóthe cortexóproduces four hormones: aldosterone, which regulates salt and water balance; hydrocortisone, which is essential for body metabolism; and both androgens and estrogens , which are the sex hormones in males and females respectively.
When excessive amounts of these hormones are produced, a variety of clinical symptoms can result, including feminization in men, masculinization in women and the signs of excessive hydrocortisone production (Cushing's syndrome). Tumors of the cortex (aldosteronoma) or of the medulla (pheochromocytoma) produce excessive amounts of aldosterone or norepinephrine, respectively causing sustained or intermittent hypertension. Tumors that produce more than one hormone are frequently malignant .
