Abstract
A case of Cushing's syndrome due to ACTH-independent bilateral macronodular adrenal hyperplasia is reported. A 46-year-old male was admitted to our hospital for further examination of hypertension. He was diagnosed as suffering from hypertension for the first time at the age of 44. Antihypertensive drug therapy with a calcium-channel antagonist or a beta blocker was tried but both had little effect. Physical examination revealed moon face and central obesity.
Complete blood counts and blood chemistry were within normal ranges but endocrinological studies showed that plasma cortisol was high (24.0μg/dl) with a lack of diurnal rhythm, and plasma ACTH was suppressed (<5pg/ml). Two or 8 mg of dexamethasone did not suppress the plasma cortisol levels. Intravenous infusion of ACTH (0.25mg) greatly raised plasma cotrisol level (380%of control). Scintigraphic imaging with 131I-adosterol revealed abnormal uptakes of bilateral adrenal glands, and computed tomography also demonstrated abnormal nodules at bilateral adrenal glands. Brain CT and MRI had no abnormal findings.
He was diagnosed as Cushing's syndrome with bilateral adrenal hyperplasia, and bilateral adrenalectomy was performed. Right and left adrenal glands were 95g and 70g, respectively, and were occupied by yellow nodular lesions. Histologically, hyperplastic lesions were composed of clear cells. Finally he was diagnosed as ACTH-independent bilateral adrenocortical macronodular hyperplasia (AIMAH).
