Tumors that occur on one or both of the adrenal glands.
The two small adrenal glands, one located just above each kidney, are among the many endocrine (hormone-secreting) glands in the body. All endocrine glands make and store hormones. Hormones are chemical messages that are sent from an endocrine gland and are received by an organ or a cell to trigger a specific reaction. When the body requires hormone levels to rise, endocrine glands secrete them into the bloodstream. Adrenal gland tumors often cause overproduction of one or a combination of the adrenal hormones.
An adrenal gland has two parts, each of which secretes different hormones. The inner part is called the adrenal medulla, and the outer part is the adrenal cortex.
The adrenal medulla secretes the hormones epinephrine and norepinephrine. These hormones help maintain normal blood pressure. In high-stress situations, they help prepare the body for quick action by increasing heartbeat and breathing rate, increasing the flow of blood to the heart and lungs, and increasing blood pressure.
The adrenal cortex secretes aldosterone and cortisol. They also make small amounts of androgens, which affect the expression of female and male sex characteristics.
Aldosterone helps maintain normal salt levels in the blood and the normal functioning of the kidneys. Cortisol (also called hydrocortisone) is the major adrenal hormone.
Cortisol is a steroid, an organic compound that affects metabolism. Many hormones and drugs used to relieve swelling and inflammation are steroids. Cortisol helps maintain blood pressure and is crucial in the breakdown of proteins, carbohydrates, and fats. It also raises blood sugar (glucose) when levels are too low, thus providing needed energy for the body's activities. Cortisol also prevents inflammation and is important for the normal response to stress.
The level of cortisol in the blood is carefully controlled. When the body needs cortisol, a small area of the brain called the hypothalamus releases coricotripoin-releasing hormone (CRH). The pituitary gland, located at the base of the brain, receives the message from the hypothalamus and begins secreting adrenocorticotropic hormone (ACTH). ACTH is received by the cortex of the adrenal glands, which responds by producing cortisol. When the level of cortisol meets the body's need, the pituitary stops producing ACTH, which then stops the adrenal cortex from secreting cortisol.
About 8% of people worldwide develop benign (noncancerous) adrenal tumors. Malignant (cancerous) tumors are very rare, occurring in two out of every one million people worldwide, and this cancer is more common in women than in men.
It is often difficult for a pathologist to distinguish between a benign and a malignant adrenal tumor. Several criteria are used to make a diagnosis, including the size and weight of the tumor, whether hormones are produced, and what hormones are produced. A benign tumor (adenoma) is usually less than 4-6 centimeters (1.57-2.3 inches) in diameter and likely causes changes in the blood level of only one hormone or may cause no changes at all. A malignant tumor is larger and may alter the level of several adrenal hormones. One reliable indicator for a malignant tumor is evidence that the cancer has spread (metastasis).
Monica McGee M.S., The Gale Group Inc., Gale, Detroit,