Three cases of clinical or preclinical Cushing's syndrome due to adrenocorticotropic hormone-independent bilateral adrenocortical macronodular hyperplasia: pituitary-adrenocortical function and immunohistochemistry.

We performed pituitary-adrenocortical function test and analysis of plasma steroids in three cases of adrenocorticotropic hormone-independent bilateral adrenocortical macronodular hyperplasia, and examined the plasma cortisol response to meal and oral glucose in two cases. On pathological examination, nodules were mainly composed of clear cells and some nests of compact cells were observed. Immunohistochemistry of steroidogenic enzymes showed positive P-450C17 only in the compact cells and positive 3 beta-hydroxysteroid dehydrogenase only in the clear cells. These cases were similar to clinical or preclinical Cushing's syndrome due to adenoma in both pituitary-adrenocortical function and plasma steroid patterns, but different from adenoma cases in the distribution of steroidogenic enzymes.