Ectopic ACTH Syndrome: Possibilities of Modern Diagnostics

The ectopic ACTH syndrome (EAS) is a constellation of clinical signs and symptoms caused by chronic excess production of cortisol by the adrenal glands due to stimulation by adrenocorticotropic hormone (ACTH) of extrapituitary origin. EAS is a rare pathology, it accounts for approximately 20% of all cases of ACTH-dependent hypercortisolism and up to 10% of all causes of endogenous autonomic cortisol production, however, it is often associated with severe hypercortisolism and is a life-threatening condition. The sources of ectopic secretion of ACTH are neuroendocrine tumors (NET), which differ in histological type, malignant potential, clinical course, and also have different, often difficult to detect localization. Early identification of ACTH -producing NET reduces the risk of death of the patient both from severe hypercortisolism and the tumor itself. The paper describes the features of the course of EAS, the possibilities of its diagnosis, and presents an algorithm for EAS diagnosis, created on the basis of the latest achievements of Russian and world medicine.