POMC and Cushing syndrome: Ectopic adrenocorticotropic hormone (ACTH) secretion syndrome is a rare clinical manifestation, but is responsible for 15% of all cases of Cushing syndrome.1 The most common ectopic ACTH‐producing tumors are thoracic (bronchial and thymic) and gastroenteropancreatic neuroendocrine tumors (NET), followed by medullary thyroid carcinoma, small cell lung cancer, and pheochromocytoma.2, 3, 4