ACTH-independent bilateral macronodular adrenocortical hyperplasia caused Cushing's syndrome.

A 53-year-old man who had been followed up for the treatment of hypertension presented with a bilateral adrenal mass during a screening CT scan. Other imaging studies and biochemical tests suggested Cushing's syndrome caused by a pituitary-independent and adrenal-dependent bilateral adrenal tumor. A total adrenalectomy was performed and the pathological appearance of the surgical specimen showed adrenal hyperplasia. Therefore, these findings were considered to be consistent with ACTH-independent bilateral macronodular adrenal hyperplasia (AIMAH). This tumor is quite rare and its etiology still remains controversial. We herein report this incidentally found AIMAH and also review the pertinent literature.