Causes Of Cushing's Syndrome

Ectopic ACTH Secretion

Ectopic ACTH secretion is an exceedingly rare occurrence. It happens when a tumor located at a site other than the pituitary gland starts producing too much ACTH. This causes the adrenal glands to produce cortisol which builds up to excessive levels. As with pituitary gland tumors, ectopic ACTH secretion is considered an ACTH-dependent disease because it is controlled by the ACTH hormone. Typically, the non-pituitary tumors that are responsible for the ectopic secretion of ACTH are found in the lungs and the thymus gland. Documented cases of these types of tumors in the thyroid, pancreas, ovaries, adrenal glands, and liver have also been reported.