Pathology General 46c5946b Most common cause of Cushing's syndrome is? A Pitutary adenoma B Adrenal adenoma C Adrenal carcinoma D McCune Albright syndrome High-Yield Explanation Ans. is 'a' i.e., Pitutary adenoma ACTH-secreting pituitary adenomas account for approximately 70% of cases of endogenous hypercoisolism (Cushing's syndrome).