[Cushing's syndrome due to huge bilateral adrenocortical multinodular hyperplasia--ACTH-independent bilateral adrenocortical macronodular hyperplasia(AIMAH)].

Six cases with ACTH-independent bilateral adrenocortical macronodular hyperplasia (AIMAH) were presented, and 21 reported cases were reviewed. Bilateral adrenal glands in AIMAH were greater than those in any other subtype of nodular hyperplasia. They were greater than 72 g in combined weight and were occupied by numerous yellow nodular/subnodular lesions. Histologically, hyperplastic lesions were composed of small compact, small clear, and usual clear cells. All of these three elements contained cells positive for PCNA but were negative for HLA-DR alpha. Small compact cells often showed positive staining for vimentin. Small cells showed underdeveloped organelles with rare nuclear grooving and were poor in lipochrome. The results are consistent with the view that AIMAH is primarily a nodular hyperplasia of the upper zona fasciculata and that it is a distinct subtype of Cushing's syndrome. Image analyses may play a major role on preoperative diagnosis of AIMAH. Bilateral adrenalectomy is the treatment of choice.