Case of adrenocorticotropic hormone-independent macronodular adrenal hyperplasia with possible adrenal hypersensitivity to angiotensin II

With increasing case reports, it has been indicated that some cases with ad renocorticotropic hormone (ACTH)-independent macronodular adrenal hyperplas ia (AIMAH) show abnormal responses in cortisol to various stimulation tests . Here we report a case of AIMAH that showed an aberrant response to angiot ensin II via AT1 receptor in cortisol hypersecretion. A 53-yr-old man was a dmitted to our division seeking further examinations for the possible diagn osis of Cushing's syndrome. He had hypertension, diabetes mellitus, and phy sical stigmata, such as moon face and central obesity. His plasma ACTH leve l was undetectable, and plasma cortisol level was high. Plasma cortisol sho wed no normal diurnal rhythm and was not suppressed after the administratio n of 8 mg of dexamethasone. Abdominal computed tomography demonstrated nodu lar enlargement of bilateral adrenal glands. He was diagnosed with Cushing' s syndrome owing to AIMAH. An injection of arginine vasopressin (AVP) incre ased plasma cortisol and aldosterone levels, whereas ACTH remained undetect able. After 4 h in an upright position, plasma cortisol and aldosterone lev els were increased. Pretreatment with candesartan, angiotensin II receptor ATI antagonist, blocked the increase in plasma cortisol level. These result s suggested a possibility of adrenal hypersensitivity to angiotensin II and AVP in cortisol secretion. Bilateral laparoscopic adrenalectomy was perfor med. The histological findings of the specimen were compatible with AIMAH. In summary, we have made the first report on a case of AIMAH with possible hypersensitivity to angiotensin II.