Tumours in the adrenal glands, usually noncancerous, that may produce excess adrenal hormones
Tumours of the adrenal glands are rare, and in 9 out of 10 cases they are noncancerous. In almost all cases, tumours occur in only one adrenal gland, and their effects depend on which part of the gland is affected. Most adrenal tumours secrete excessive amounts of one or more of the adrenal hormones, which can upset metabolism (the chemical reactions constantly occurring in the body) and water balance and may alter the body’s response to physical stress such as injury.
Adrenal tumours can develop in either the cortex (outer layer) or the medulla (centre) of the adrenal gland.
Adrenal tumours in the cortex may secrete corticosteroids, aldosterone, or androgens (male sex hormones). Over-production of corticosteroids leads to changes in physical appearance as well as in body chemistry (see Cushing’s syndrome) and may cause serious complications. An excess of the hormone aldosterone, a condition known as hyperaldosteronism, disturbs the body’s salt and water balance and is a rare cause of high blood pressure (see Hypertension). A high level of androgens in women may lead to the development of male characteristics (see Virilization); in males, an excess often goes unnoticed.
Tumours that develop in the adrenal medulla are known as phaeochromocytomas. These tumours produce large amounts of either or both of the hormones epinephrine (adrenaline) and norepinephrine (noradrenaline), excessive levels of which cause sweating, high blood pressure, and palpitations.
Adrenal tumours are usually diagnosed by detecting abnormal levels of adrenal hormones in the blood. Imaging tests, such as MRI and CT scanning, may also be carried out to look for abnormalities in the adrenal glands.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.