Latent Autonomous Cortisol Secretion From Apparently Nonfunctioning Adrenal Tumor in Nonlateralized Hyperaldosteronism

CONTEXT: Adrenal tumors (ATs), even those diagnosed as nonfunctioning, may cause metabolic disorders. Some primary aldosteronism (PA) patients with ATs are diagnosed with bilateral PA based on adrenal venous sampling (AVS), and their ATs are apparently nonfunctioning. OBJECTIVE: To clarify the influence of apparently nonfunctioning ATs, we compared hormone levels and clinical complications between bilateral PA cases with and without ATs. DESIGN, SETTING, AND PARTICIPANTS: After retrospectively assessing 2814 patients with PA in the multicenter Japan PA study, bilateral PA cases on AVS were divided into cases with and without ATs by computed tomography findings. Importantly, patients with cortisol levels >1.8 µg/dL after the 1-mg dexamethasone suppression test (DST) were excluded. Clinical characteristics and biochemical data were compared between them. The correlation between AT size and hormone levels was also analyzed. MAIN OUTCOME MEASURES: Analyzed were 196 bilateral PA patients with ATs and 331 those without ATs. Although basal cortisol and aldosterone levels were similar between them, cortisol levels after the 1-mg DST and the prevalences of diabetes mellitus and proteinuria were significantly higher and ACTH levels and plasma renin activity were significantly lower in cases with ATs than in those without. After adjusting for patients' backgrounds, cortisol levels after the 1-mg DST and plasma renin activity remained significantly different between them. Moreover, cortisol levels after the 1-mg DST and ACTH levels correlated with AT size. CONCLUSIONS: Apparently nonfunctioning ATs in bilateral PA cases may cause latent autonomous cortisol secretion, inducing diabetes and proteinuria.