<prompt> Commonest cause of Cushing syndrome isAdrenal adenomaCarcinomaAtrophyHyperplasia  <response>: MC cause of Cushings syndrome is iatrogenic exogenous administration of steroids. MC endogenous cause of Cushings syndrome is bilateral adrenal hyperplasia secondary to hypersecretion of ACTH from pituitary or from an ectopic non-pituitary source 