The clinical conundrum of corticotropin-independent autonomous cortisol secretion in patients with bilateral adrenal masses

Background: Management of patients with bilateral adrenal masses and corticotropin (ACTH)-independent Cushing syndrome (CS) or subclinical CS is problematic. We report our experience with adrenal venous sampling (AVS) in the evaluation of 10 patients with bilateral masses who had ACTH-independent CS or subclinical CS. Patients and Methods: Ten patients (9 women, 1 man, mean age 56.4 years) with bilateral adrenal masses and ACTH-independent CS (n = 3) or subclinical CS (n = 7) underwent AVS. Autonomous cortisol secretion was documented in all cases with suppressed serum ACTH concentrations and lack of cortisol suppression with dexamethasone administration. Adrenal venous sampling was performed on the second day of dexamethasone administration. Cortisol and epinephrine levels were measured from each adrenal vein (AV) and from a peripheral vein (PV). Results: Mean (± SD) maximal diameter of the adrenal masses on computed tomography was 3.3 ± 1.3 cm (range: 1.2-6.0 cm). Successful catheterization was confirmed with AV:PV epinephrine gradients. A cortisol AV:PV gradient >6.5 was consistent with a cortisol-secreting adenoma in 11 adrenal glands; 5 patients had clinically important bilateral autonomous cortisol hypersecretion, 3 had bilateral cortisol-secreting adenomas, and 2 had ACTH-independent macronodular adrenal hyperplasia. Adrenal venous sampling-guided adrenalectomy was completed in all 10 patients-2 patients had total bilateral adrenalectomy and 2 others had subtotal bilateral adrenalectomy. During a mean follow-up of 36.1 months (range: 0.7-123 months), CS or clinically important cortisol secretory autonomy did not recur. Conclusions: Adrenal venous sampling contributed to the localization of autonomous hypercortisolism in the setting of ACTH-independent CS or subclinical CS in patients with bilateral adrenal masses.