POMC and Cushing syndrome: Naturally occurring Cushing's syndrome, hereby referred to as Cushing's syndrome, is an endocrine disorder that results from chronic excessive production of glucocorticoids, due to an adrenocorticotropic hormone (ACTH) secreting pituitary mass, a glucocorticoid secreting adrenal tumour, or other rarer aetiologies (Behrend et al. 2013, Nelson & Couto 2014).