ADRENOCORTICOTROPIN-INDEPENDENT BILATERAL MACRONODULAR ADRENOCORTICALHYPERPLASIA - IMMUNOHISTOCHEMICAL STUDIES OF STEROIDOGENIC ENZYMES AND POSTOPERATIVE COURSE IN 2 MEN

We treated two men with Cushing's syndrome due to adrenocorticotropin (ACTH)-independent bilateral macronodular adrenocortical hyperplasia ( AIMAH). In both patients, plasma ACTH was low and plasma cortisol was not suppressed by a high dose of dexamethasone (8 mg) but was remarkab ly responsive to exogenous ACTH. The adrenal glands were extremely enl arged and contained multiple nodules composed of large clear cells and small compact cells. The immunoreactivity of P-450(17 alpha) was pred ominant in the small compact cells, while that of 3 beta-hydroxysteroi d dehydrogenase (3 beta-HSD) was observed exclusively in the large cle ar cells. Among various adrenocortical disorders, differential express ion of 3 beta-HSD and P-450(17 alpha) in clear and compact cells has h eretofore been demonstrated only in AIMAH. Total adrenalectomy was don e for one patient, and partial adrenalectomy for the other. In the for mer patient, the normal diurnal rhythm of plasma ACTH was restored 11 months postoperatively. In the latter patient, the normal dynamics in the hypothalamic-pituitary-adrenal axis became evident 15 months after surgery. Thus AIMAH is apparently a primary adrenocortical disorder a nd is not due to abnormalities of the hypothalamus or pituitary.