Ectopic ACTH is commonly secreted by: September 2007

Ans. A: Small cell carcinoma of the lungs Endogenous Cushing's syndrome results from some derangement of the body's 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 Cushing's, a benign pituitary adenoma secretes ACTH. This is also known as Cushing's disease and is responsible for 65% of endogenous Cushing's syndrome. In adrenal Cushing's, 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 Cushing's syndrome and is seen in diseases like small cell lung cancer.