POMC and adenoma: In NSS, adrenalectomy removes cortisol-mediated negative feedback on the adenoma remnant, which may rapidly progress and yield a large adrenocorticotropic hormone (ACTH)-secreting macroadenoma and, in the classic description, precipitating visual field deficits from chiasmatic compression, and skin hyperpigmentation from the marked increase in circulating alpha-melanocyte-stimulating hormone-a metabolic byproduct of ACTH synthesis.