What causes Cushing’s syndrome and Cushing’s disease?
Cushing’s syndrome can be caused by medication or by a tumor. Sometimes, there is a tumor of the adrenal gland that makes too much cortisol. It may also be caused by a tumor in the pituitary gland (a small gland under the brain that produces hormones that in turn regulate the body’s other hormone glands).
Some pituitary tumors produce a hormone called adrenocorticotropic hormone (ACTH), which stimulates the adrenal glands and causes them to make too much cortisol. This is termed Cushing’s disease. ACTH-producing tumors can also originate elsewhere in the body and these are referred to as ectopic tumors.
See Figure 1 for an illustration of the differences between these three situations. It is important to note that pituitary tumors are almost never cancerous.
View Figure 1: The various causes of Cushing’s syndrome (this will open in a new browser window)
