<prompt> Most common cause of Cushings syndrome isExogenous coicosteroidsPituitary tumorAdrenal adenomaAdrenal carcinoma  <response>: Causes of Cushing Syndrome: - Exogenous : External supplementation of glucocoicoids - Most common cause - Endogenous : Pituitary adenoma Ectopic ACTH secretion - Small cell lung cancer; Medullary thyroid cancer etc Adrenal causes - Adrenal hyperplasia adenoma cancer 