<prompt> Ectopic ACTH is commonly secreted by:September 2007Small cell carcinoma of the lungsPancreatic carcinomaGall bladder malignancyMedullary carcinoma of thyroid  <response>: Ans. A: Small cell carcinoma of the lungsEndogenous Cushings syndrome results from some derangement of the bodys own system of secreting coisol. Normally, ACTH is released from the pituitary gland when necessary to stimulate the release of coisol from the adrenal glands.In pituitary Cushings, a benign pituitary adenoma secretes ACTH. This is also known as Cushings disease and is responsible for 65 of endogenous Cushings syndrome.In adrenal Cushings, excess coisol is produced by adrenal gland tumors, hyperplastic adrenal glands, or adrenal glands with nodular adrenal hyperplasia.Finally, tumors outside the normal pituitary-adrenal system can produce ACTH that affects the adrenal glands. This final etiology is called ectopic or paraneoplastic Cushings syndrome and is seen in diseases like small cell lung cancer. 