Although hypothalamic-pituitary-adrenal suppression can be caused by cortisol-producing adrenocortical tumors, even in patients with preoperative hypercortisolism (e.g., clinical and subclinical Cushing syndrome), unilateral adrenalectomy rarely causes long-term irreversible adrenal insufficiency.[3] However, Yokoyama and Tanaka[2] have reported that unilateral adrenalectomy might cause irreversible impairment of adrenocortical function, and that patients had markedly elevated ACTH levels and normal serum cortisol levels after ipsilateral adrenalectomy and radical nephrectomy for RCC. This evidence concerns the gene POMC and Adrenal insufficiency.