DefinitionCushing's disease is a condition in which the pituitary gland releases too much adrenocorticotropic hormone (ATCH). The pituitary gland is an organ of the endocrine system.Cushing's disease is a form of Cushing syndrome.Alternative NamesPituitary Cushing's diseaseCauses, incidence, and risk factorsCushing's disease is caused by a tumor or excess growth (hyperplasia) of the pituitary gland. This gland is located at the base of the brain.People with Cushing's disease have too much ACTH. ACTH stimulates the production and release of cortisol, a stress hormone. Too much ACTH means too much cortisol.Cortisol is normally released during stressful situations. It controls the body's use of carbohydrates, fats, and proteins and also helps reduce the immune system's response to swelling (i