Inappropriate ACTH secretion syndrome, also known as ectopic Cushing syndrome, is a medical condition characterized by abnormal and excessive production of adrenocorticotropic hormone (ACTH) from non-pituitary tumors or cells. ACTH is normally secreted by the pituitary gland and plays a crucial role in regulating the production and release of cortisol from the adrenal glands.
In cases of inappropriate ACTH secretion syndrome, an ectopic tumor or cells outside of the pituitary gland begin to produce and secrete ACTH. This abnormal ACTH production leads to an overstimulation of the adrenal glands, causing them to produce excessive amounts of cortisol. As a result, the levels of cortisol in the blood become elevated, leading to the development of symptoms commonly associated with Cushing syndrome.
The primary cause of inappropriate ACTH secretion syndrome is the presence of non-pituitary tumors, such as small cell lung cancer, carcinoid tumors, pancreatic neuroendocrine tumors, or medullary thyroid cancer. These tumors or cells possess receptors that are sensitive to ACTH, leading to its uncontrolled production and release.
The symptoms of inappropriate ACTH secretion syndrome typically include weight gain, particularly in the face, neck, and trunk, fatty deposits in the upper back (buffalo hump), purple or pink stretch marks on the skin, thinning of the skin, muscle weakness, increased blood pressure, glucose intolerance or diabetes, mood swings, and menstrual irregularities in women.
Treatment for inappropriate ACTH secretion syndrome involves identifying and treating the underlying non-pituitary tumor. Surgical removal, chemotherapy, radiation therapy, or targeted drug therapies may be employed depending on the nature and location of the tumor. Additionally, medications that block the production or action of cortisol may be prescribed to manage the
