Primary aldosteronism associated with subclinical Cushing syndrome

Background: Recently, it has been reported that the incidence of primary aldosteronism (PA) among patients with hypertension is much more frequent than previously reorted. Aim: In the present study, we investigated the frequency and features of PA associated with subclinical Cushing syndrome (SCS). Material and methods: Subjects included consecutive patients (no.=39) who were diagnosed as PA and performed adrenal venous sampling between 2003 and 2011 in our institute. Results: In 39 subjects who were diagnosed as PA, 29 patients were operated and 5 cases (12.8%) showed no suppression in low-dose dexamethasone suppression test. Four cases of them were demonstrated to be associated with SCS, and one was associated with overt Cushing syndrome (CS). Post-operatively, 3 cases received replacement therapy of hydrocortisone, while others did not. Pathological findings indicated the diagnosis of aldosterone-producing adenoma in 4 cases associated with SCS, and of idiopathic hyperaldosteronismin in one case associated with overt CS. In all 5 cases, immunohistochemical analysis demonstrated the immunoreactivities of both 3βHSD and P450c17 in the adrenocortical tumors, the marked cortical atrophy in the zona fasciculata and reticularis , the decreased dehydroepiandrosterone sulfotransferase expression, and suppression of hypothalamo-pituitary-adrenal axis indicating the autonomous secretion of cortisol from the tumor. Conclusions: The present study suggests that PA is frequently associated with SCS with prevalence of more than 10%, justifying the routine examinations for SCS in PA cases.