The Role of Unilateral Adrenalectomy in Corticotropin-Independent Bilateral Adrenocortical Hyperplasias

The objective of the present study was twofold: to demonstrate our experience with unilateral adrenalectomy in the treatment of adrenocorticotropic hormone (ACTH)-independent Cushing syndrome (CS) caused by bilateral adrenocortical hyperplasias, and to evaluate the long-term results as evidenced by the main laboratory and clinical findings. From February 2000 to August 2009, unilateral adrenalectomy was performed on 27 patients with ACTH-independent CS and bilateral adrenocortical hyperplasias, including 14 patients with ACTH-independent macronodular adrenal hyperplasia (AIMAH) and 13 patients with primary pigmented nodular adrenocortical disease (PPNAD). Signs and symptoms of CS, endocrine examinations, and radiographic imaging were evaluated preoperatively and postoperatively. At a median follow-up of 69 months (range: 23-120 months) for AIMAH and 47 months (range: 16-113 months) for PPNAD, 25 patients were cured by unilateral adrenalectomy. Serum cortisol level, daily urinary free cortisol (UFC), and plasma ACTH regained the normal range in both AIMAH and PPNAD patients at monthly follow-up visits; the circadian serum cortisol rhythm returned to normal, and a normal responsiveness to overnight low-dose dexamethasone administration (LDDST) became obvious. Both systolic and diastolic blood pressure (BP) levels were significantly reduced: 85 % of patients recovered normal BP levels, and the remaining patients need antihypertensive drugs, but at a reduced dose. No surgery-related morbidity occurred, and there was no sign of further enlargement of the residual adrenal gland after successful unilateral adrenalectomy. One patient with PPNAD and another patient with AIMAH with similar weights and sizes of the bilateral adrenals needed contralateral adrenalectomy. Unilateral adrenalectomy may be the suitable treatment for selected patients with AIMAH and PPNAD. It can achieve long-term remission of CS and improve glycemic control and BP values.