Adrenocorticotropic hormone-independent bilateral macronodular adrenocortical hyperplasia associated with Cushing's syndrome.

A case of adrenocorticotropic hormone independent bilateral adrenocortical macronodular hyperplasia (AIMAH) is reported. A 59 year old male was admitted to hospital because of hypertension. Subsequently, hypercortisolism, low plasma adrenocorticotropic hormone (ACTH), loss of diurnal rhythm of ACTH, lack of suppression with high dose dexamethasone were found and bilateral adrenal enlargement was detected by abdominal computerized tomography and adrenal scintigraphy. Bilateral total adrenalectomy was performed under a diagnosis of bilateral adrenal hyperplasia associated with Cushing's syndrome. Both adrenal glands were enlarged in size and weight. Bulging nodules were found at the cut section. Microscopically, a variegated histologic pattern including trabecular, adenoid and zona glomerulosa-like (ZG-like) structures was revealed in the nodules. Immunohistochemical examination disclosed positive staining of cytochrome P-450 17 alpha, negative of 3 beta-HSD in the ZG-like structure. Ultrastructurally, the cells composing the ZG-like structure were similar to those of the ZG in normal adrenal cortex. The authors agree that AIMAH is one of the entities causing Cushing's syndrome, and advise pathologists to keep this disorder in mind when they examine the adrenals in Cushing's syndrome.