Primary Aldosteronism Caused by a Unilateral Adrenal Adenoma Accompanied by Autonomous Cortisol Secretion

Abstract

A 35-year-old Japanese woman was referred for further examination of persistent hypertension with hypokalemia. Her serum aldosterone levels were high and her plasma renin activity markedly suppressed. Radiological examinations revealed the presence of a 3-cm diameter left adrenal tumor. (131)I-adosterol was specifically accumulated in the left adrenal tumor, whereas the accumulation in the right adrenal was completely suppressed. Low-dose dexamethasone failed to suppress cortisol secretion although the serum cortisol levels were within the normal range. Urinary excretion of 17-hydroxycorticosteroids but not 17-ketosteroids was increased. Levels of plasma adrenocorticotropin (ACTH) and serum dehydroepiandrosterone sulfate (DHEAS) were decreased. Upon diagnosis of left aldosteronoma with autonomous secretion of cortisol, left adrenalectomy was performed by laparoscopy. In the resected adenoma tissues, clear cells expressed P450c17 protein and the ratio of CYP17/CYP11B2 mRNA evaluated by quantitative real-time polymerase chain reaction (PCR) was apparently higher than that of typical aldosteronomas. Based on the corticotropin-releasing hormone (CRH) loading tests, the contra-lateral adrenal functions were restored 3 months after surgery. These results indicate that evaluation for autonomy of cortisol secretion and contra-lateral adrenal function is clinically important to avoid the risk of adrenal failure after surgery for primary aldosteronism.