Ectopic ACTH secretion

Hypercortisolism may also be due to ectopic secretion of ACTH usually by tumors, most commonly Small-Cell Lung Cancer, thymoma, carcinoid tumors, pheochromocytomas, and medullary thyroid carcinoma. In addition to findings of Cushing’s syndrome, patients are typically cachectic due to the malignancy which is usually rapidly fatal.

Ectopic adrenocorticotropic hormone secretion (EAS) is responsible for approximately 10-15% cases of Cushing's syndrome. EAS is associated with various tumors such as small cell lung cancer and well-differentiated bronchial or gastrointestinal neuroendocrine tumors. Hormonal diagnostics include assessments in basic conditions as well as dynamic tests, such as the high-dose dexamethasone suppression test and corticotrophin releasing hormone (CRH) stimulation test. Treatment selection depends on the type of tumor and its extent. In the case of neuroendocrine tumors, the main treatments are surgery and administration of somatostatin analogs that may be additionally radiolabeled for targeted radiotherapy. The tumor histology and the presence and control of hypercortisolemia and metastases are of major importance in prognosis ¹⁾.