Proliferating cell nuclear antigen in ACTH-independent bilateral macronodular adrenal hyperplasia

ACTH-independent bilateral macronodular adrenal hyperplasia (AIMAH) has been recently described as a rare cause of Cushing's syndrome and it is an unusual process of unknown etiology. This report describes a case of a 59-year-old man with AIMAH. The proliferating cell nuclear antigen (PCNA) has been implicated in the process of cell proliferation and is detectable throughout most of the cell cycle. This report also describes the expression of PCNA in AIMAH by immunohistochemical staining. Most of the positive expression was seen in the greater part of the epithelial cells of the cortical lesion, but not in the interstitial cells. These data suggest that some effective factor, specific for adrenal cortical cell growth, might be produced in AIMAH.