ACTH-independent macronodular adrenal hyperplasia: report of 12 cases

Abstract

Objective To explore the diagnosis and treatment of adrenocorticotropin-independent macronodular adrenal hyperplasia (AIMAH). Methods The clinical symptoms, endocrinological and radiological characteristics, treatment modalities, and postoperative clinical course of 12 AIMAH patients were retrospectively reviewed. There were 5 men and 7 women with an average age of 48 years old. Results All cases had some clinical features and biochemical evidence of Cushing's syndrome. The circadian rhythm of serum cortisol was abnormal. Low- and high-dose dexamethasone suppression tests failed to suppress cortisol secretion. CT or MRI scan showed bilateral enlargement of the adrenal glands with multiple macronodules. Bilateral adrenalectomy was performed in three patients and unilateral adrenalectomy combined with contralateral subtotal adrenalectomy was performed in one patient. Seven patients underwent unilateral adrenalectomy of the larger gland. The removed adrenal glands weighted within 8-96 g range and pathologic diagnoses were nodular or adenomatoid hyperplasia of adrenal cortex. The duration of postoperative follow-up was 14 to 124 months. Clinical symptoms of Cushing's syndrome disappeared after surgery in all cases and there was no Nelson's syndrome after bilateral adrenalectomy. Urinary free cortisol and serum cortisol were within normal ranges. No further enlargement of the contralateral gland has been noticed in patients who received unilateral adrenalectomy during the follow-up.Conclusions AIMAH had unique endocrinological and pathological features. Unilateral adrenalectomy appears to be an effective and safe alternative treatment for AIMAH. Bilateral adrenalectomy or unilateral adrenalectomy combined with contralateral subtotal adrenalectomy may be performed if the symptoms had not been improved or recurred after unilateral adrenalectomy. Key words: Cushing's syndrome; Corticotropin; Macronodular adrenal hyperplasia