Endocrine Abstracts

Background: ACTH-independent Cushing’s syndrome (AICS) due to bilateral adrenal lesions (BAL) is a challenge as determining whether autonomous cortisol secretion is unilateral or bilateral is crucial in guiding the treatment strategy.

Aim: To analyse the usefulness of adrenal venous sampling (AVS) in differentiating between unilateral and bilateral cortisol secretion in patients with AICS and BAL.

Methods: We performed a retrospective single center analysis of 6 patient cases with AICS who had AVS done at Vilnius University Hospital Santaros Klinikos between 2018 and 2023. AICS diagnosis was clarified by 1 mg dexamethasone suppression test as well as testing late night cortisol, 24 h urine cortisol and ACTH. Successful cannulation was defined as adrenal to peripheral vein ratio of aldosterone >2. Unilateral cortisol secretion was defined as side-to-side lateralization index >2 using aldosterone as a reference hormone.

Results: Concomitant diseases were diagnosed as follows: hypertension – in all 6 patients, dyslipidemia – in 4, osteoporosis – in 2 (with multiple fractures in one case), cardiovascular diseases – in 1, diabetes – in 1 patient. Two out of six patients presented with overt Cushing’s syndrome. Both had BAL on computed tomography (CT). Based on the AVS results, one of these patients had unilateral secretion and percutaneous radiofrequency ablation of the functioning tumor was performed. Following the ablation the patient developed transient adrenal insufficiency and was treated with hydrocortisone for two years. The other patient underwent bilateral adrenalectomy. Mild autonomous cortisol secretion was diagnosed in four other patients – all of which showed BAL on CT. One of these patients had unilateral cortisol secretion based on the AVS results and is scheduled for a unilateral adrenalectomy. The remaining three patients had different treatment strategies - one of them underwent unilateral adrenalectomy which did not result in adrenal insufficiency. Furthermore, this led to the discontinuation of antihypertensive treatment as blood pressure normalized. The second patient underwent a two-stage bilateral laparoscopic adrenalectomy with a break of 3 months between operations when hypercortisolism remained after the first one. The third patient had bilateral adrenalectomy.

Conclusions: AVS is an important procedure that may contribute to appropriate treatment in patients with AICS and BAL. In our case, AVS helped to avoid unnecessary bilateral adrenalectomies in 2 out of 4 cases. However, the rare clinical scenario of BAL needs an individualised treatment approach based on the agreement of both the patient and the medical team.