POMC and pituitary tumor: A recent expert consensus recommended that radiological evidence of corticotroph tumour progression or new detection of a radiologically visible pituitary tumour after BLA should be considered as the primary criterion for the definition and diagnosis of NS [given that modern imaging methods (especially MRI) allow earlier detection of tumour growth (even before clinical manifestations become evident)]; hyperpigmentation and progressive increase of plasma ACTH levels after BLA should be considered as non-mandatory secondary criteria for the diagnosis (Table 1) [2].