POMC and pituitary gland adenoma: In around 80% of cases, the pathognomonic glucocorticoid excess is due to an inappropriate secretion of adrenocorticotropic hormone (ACTH) by a pituitary adenoma, whereas ectopic and adrenal tumours (with concomitant ACTH- or cortisol-over-secretion) are responsible for 10% of cases each [1, 2].