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What is Ectopic ACTH syndrome is seen most commonly with and explain in detail?
* Ectopic ACTH production is predominantly caused by occult carcinoid tumors, most frequently in the lung, but also in thymus or pancreas. * Advanced small cell lung cancer can cause ectopic ACTH production. In rare cases, ectopic ACTH production has been found to originate from medullary thyroid carcinoma or pheochromocytoma, the latter co-secreting catecholamines and ACTH.