The role of unilateral adrenalectomy in ACTH-independent macronodular adrenal hyperplasia (AIMAH)

Background ACTH-independent macronodular adrenal hyperplasia (AIMAH) is a rare cause of Cushing's syndrome. Bilateral adrenalectomy is considered the treatment of choice, with subsequent lifetime steroid replacement, but unilateral adrenalectomy has been recently proposed to reduce the secreting tissue. This prospective study was designed to evaluate the long-term results of unilateral adrenalectomy in AIMAH concerning the main laboratory and clinical abnormalities and the patient's quality of life. Methods Seven consecutive patients with confirmed AIMAH underwent unilateral adrenalectomy of the largest gland. ACTH and cortisol levels, arterial blood pressure (BP), glycometabolic parameters, and patient's subjective perception of health-related quality of life (by the SF-36 questionnaire) were measured preoperatively and postoperatively. Results No surgery-related morbidity occurred. One patient with a large contralateral adrenal enlargement required a completion adrenalectomy after 7 months because of persistent hypercortisolism. At a median follow-up of 53 (range, 27-68) months, the remaining six patients were cured, because serum and urinary free cortisol levels significantly decreased and ACTH increased, thus regaining the normal range. Both systolic and diastolic BP levels significantly reduced: 50% of patients definitively became normotensive, and the remaining patients reduced the need for antihypertensive treatment; 40% of patients suffering from preoperative diabetes were cured, whereas 40% reduced the need for hypoglycemizing drug. SF-36 evaluation of the health-related quality of life confirmed a significant amelioration. Conclusions Unilateral adrenalectomy of the largest gland can be an effective and safe treatment for AIMAH in case of asymmetric involvement. It may achieve long-term remission of Cushing's syndrome and improve BP values, glycemic control, and patient's quality of life.