Ectopic ACTH syndrome is seen most commonly with: (A) Renal cell carcinoma, (B) Lymphoma, (C) Bronchogenic carcinoma, (D) Pituitary adenoma
Answer is C. * 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.