Extra-pituitary ACTH hypersecretion commonly occurs in neuroendocrine tumors of various tissue types, including small-cell lung carcinomas (SCLCs), bronchial carcinoids, thymic neuroendocrine neoplasms (NENs), pheochromocytomas, and medullary thyroid carcinomas [111,112,113,114,115,116,117,118,119,120,121]. This evidence concerns the gene POMC and hereditary pheochromocytoma-paraganglioma.