Endocrine Abstracts

Introduction: Adrenal Cushing’s syndrome accounts for 15-20% of all the causes of endogenous hypercortisolism, mainly due to unilateral adenomas and adrenal cancer. Approximately 9-17% of patients with ACTH-independent Cushing’s syndrome have bilateral adrenal adenomas. Subsequently, their management is quite demanding. The main difficulty lies in distinguishing between a functional and a non-functional adrenal mass, since this cannot be reliably achieved by routine imaging and laboratory tests. Although adrenal-venous-sampling(AVS) is a widely used method for the diagnosis of primary hyperaldosteronism, it’s utility in distinguishing bilateral or unilateral cortisol overproduction, has only been evaluated by a few studies.

Case Report: A 68-year-old man, was referred to our department due to severe osteoporosis and vertebral fractures. The patient had a history of 4.5 cm right adrenal adenoma known for the past 15 years. At that time, according to the clinical evaluation and laboratory findings, no adrenal dysfunction was detected and the possibility of malignancy was ruled out. For this reason, despite medical recommendations, he did not wish to be operated on. However, 3 years ago, a slight increase in the size of the adenoma (5.5×5.4 cm) and a marginally increased urinary-free-cortisol (UFC) 160 μg/24 h (20-90) were found. During the next months he reported low back pain, steadily worsening proximal muscle wasting and weakness, while the diagnosis of severe osteoporosis and vertebral fractures was made. Upon his arrival at our department, he had typical signs of hypercortisolism. New imaging and laboratory tests were performed. The Computed-Tomography (CT) showed the known adenoma, as well as the presence of a 1 cm adenoma in the left adrenal gland. Both, baseline and overnight 1 mg Dexamethasone-suppression-test (DST), cortisol and ACTH values, established the diagnosis of Cushing’s syndrome. The patient underwent adrenal-venous-sampling (AVS), to determine the location of cortisol hypersecretion, because bilateral adrenalectomy was extremely likely. Adrenaline was used as reference hormone for Selectivity-Index(SI) and Lateralization- index (LI), and the results were compatible with hypersecretion of the right adenoma, therefore a right adrenalectomy was performed. The patient’s postoperative course was satisfactory, with a gradual improvement of all the affected metabolic factors(especially bone metabolism). He continues to need hormone replacement with hydrocortisone one year after surgery.

Conclusion: Adrenal venous sampling (AVS), in patients with Cushing’s syndrome and bilateral adrenal adenomas, is a useful tool, for distinguishing between bilateral and unilateral cortisol hypersecretion. However, the results require careful evaluation, along with clinical, biochemical and imaging findings. Larger studies are needed, to establish a specific method of performing and interpreting this test.