Role of adrenal venous sampling in the differential diagnosis of ACTH-independent Cushing’s syndrome with bilateral adrenal mass

Purpose: The diagnosis and management of corticotropin-independent Cushing’s syndrome (AICS) with bilateral adrenal mass remain challenging. Some studies have explored the value of adrenal vein sampling (AVS) in patients with AICS; however, more investigations are needed to assess its benefits for diagnosis and treatment planning in this population. Methods: Ten patients with imaging and biochemical evidence of AICS received AVS at our institution from 2017-2021, and their data, including demographics, laboratory results, adrenal mass and clinical characteristics, were analyzed. Serum cortisol and plasma aldosterone concentrations of the adrenal vein and inferior vena cava were measured. AVS-guided adrenalectomy was performed. Histology and immunohistochemistry of the adrenal tissues were analyzed. The prognosis was evaluated based on symptomatic improvement, serum cortisol normalization or both. Results: : Bilateral adrenal mass were noted via computed tomography imaging in ten patients. The mean (± SD) maximal diameter of the adrenal mass was 1.84±0.93 cm (0.4-3.4 cm). Blood samples were successfully collected from both adrenal veins and inferior vena cava in seven patients, with lateralization index values ranging from 1.00-3.38. Blood from the right adrenal vein was not collected in three patients; instead of the lateralization index, their left adrenal vein to inferior vena cava cortisol gradient was analyzed. The AVS and postoperative pathological results were consistent. During the mean follow-up of 45.7 months, all ten patients achieved clinical improvement. Conclusion: Our study suggested that AVS helps distinguish unilateral disease from bilateral disease and localize autonomous hypercortisolism glands, thereby improving therapeutic strategy selection for patients with AICS and bilateral adrenal mass.