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 reported. 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.