POMC and adenoma: CS can be classified in ACTH-dependent and ACTH-independent forms; the ACTH-dependent forms are due to the presence of an ACTH-secreting pituitary tumour (70% of cases), named Cushing’s disease (CD), or an ACTH-secreting or corticotropin-releasing hormone-secreting ectopic tumour (10% of cases), named ectopic CS, whereas the ACTH-independent forms are due to the presence of a cortisol-secreting adrenal lesion, including bilateral adrenal hyperplasia or dysplasia, adenoma or carcinoma (20% of cases), named adrenal CS [1, 2].