Most common cause of Cushing's syndrome is -

Ans. is 'a' i.e., Pituitary adenoma o ACTH-secreting pituitary adenomas account for approximately 70% of cases of endogenous hypercortisolism (Cushing's syndrome).Endogenous Causes of Cushing SyndromeCauseRelative Frequency (%)Ratio of Females to MalesACTH-DEPENDENT# Cushing disease (pituitary' adenoma; rarely CRH dependent pituitary hyperplasia)# Ectopic corticotropin syndrome (ACTH-secreting pulmonary' small cell carcinoma, bronchial carcinoid).703[?]5:1[?]0101:1ACTH-IN DEPENDENT# Adrenal adenoma# Adrenal carcinoma# Macronodular hyperplasia (ectopic expression of hormone receptors, including GIPR, LHR, vasopressin and serotonin receptors).# Primary' pigmented nodular adrenal disease (PRKARIA and PDE11 mutations).# McCune-Albright syndrome (GNAS mutations)105<24:11:11:1<21:1<21:1