ADRENOCORTICOTROPIC HORMONE-INDEPENDENT BILATERAL ADRENOCORTICAL MACRONODULAR HYPERPLASIA - A CASE-REPORT AND IMMUNOHISTOCHEMICAL STUDIES

A 55-year-old woman developed Cushing's syndrome due to ACTH-independe nt bilateral adrenocortical macronodular hyperplasia. Plasma ACTH was undetectable, and was not stimulated by administration of metyrapone, CRH, or insulin. Hypercortisolism was not suppressed by a high dose of dexamethasone, but was responsive to ACTH. Both adrenal glands were e nlarged with a total weight of 200 g, and contained multiple nodules c omposed of two cell types (large clear cells and small compact cells). In immunohistochemical studies, P450c17 immunoreactivity was predomin antly observed in small compact cortical cells, while that of 3 beta H SD was observed exclusively in large clear cortical cells. This patter n of expression of steroidogenic enzymes as well as histological and c linical features is considered to be unique to ACTH-independent bilate ral adrenocortical macronodular hyperplasia.