Role of adrenal venous sampling in the differential diagnosis and treatment protocol of ACTH-independent Cushing's syndrome with bilateral adrenal lesions

Abstract

Purpose: The diagnosis and management of adrenocorticotropic hormone-independent Cushing's syndrome (AICS) with bilateral adrenal lesions 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: Thirteen patients with clinical, biochemical and imaging evidence of AICS with bilateral adrenal lesions underwent AVS in our department from 2017-2022 were recruited. Only the data from nine patients for whom AVS succeeded were finally included in this study and further analyzed. Blood samples were successfully collected from both adrenal veins (AV) and inferior vena cava (IVC) in these nine patients, and the levels of plasma total cortisol (PTC) and plasma aldosterone concentrations (PAC) were measured. The ratio of the PAC of the AV to the IVC was calculated, and the PTC to PAC ratios were compared between AV. The surgical strategy was chosen according to the results of AVS. Postoperative histology and immunohistochemistry of the adrenal tissues were performed. The prognosis was evaluated based on the improvement of clinical symptoms and biochemical parameters (including PTC and ACTH measurements).

Results: Patients with AICS were clinically diagnosed based on clinical signs, results of functional tests and the presence of bilateral adrenal lesions as observed on computed tomography imaging. An AV to IVC PAC ratio greater than 2 confirmed successful AVS. The PTC to PAC ratio (high side to low side) was greater than 2 in four patients, and less than 2 in five patients. The postoperative pathological results were consistent with clinical diagnosis and AVS. During the mean follow-up of 33 months, all nine patients achieved varying degrees of clinical improvement.

Conclusion: Our study showed that AVS helped to distinguish unilateral and bilateral lesions, identify the laterality of the autonomous hypercortisolism, and improve therapeutic strategy selection in patients with AICS and bilateral adrenal lesions.

Keywords: ACTH-independent Cushing’s syndrome (AICS); Adrenal vein sampling (AVS); Bilateral adrenal lesions; Differential diagnosis; Treatment protocol.