Yamada T, Fukuoka H, Hosokawa Y, et al. - Researchers undertook this retrospective single-center, cross-sectional analysis to evaluate the plasma renin activity (PRA), plasma aldosterone concentration, as well as aldosterone renin ratio (ARR) in patients suffering from pheochromocytoma (PCC), relative to those in patients with subclinical Cushing’s syndrome (SCS) and non-functioning adrenal adenoma (NFA). This study involved 67 consecutive patients with adrenal tumors (PCC (n = 18), SCS (n = 18), and NFA (n = 31)). Patients with PCC had significantly higher PRA, vs those with SCS and NFA. In receiver operating characteristic curve analysis, a sensitivity of 70.0% and specificity of 80.6% was afforded by PRA > 1.55 ng/mL/h for distinguishing PCC from NFA. A sensitivity of 83.3% and specificity of 86.7% was demonstrated by ARR < 95.4. Overall, findings revealed reduced ARR in patients with PCC, and showed a greater sensitivity of ARR compared with PRA as a marker.