Endocrine Abstracts

Background: ACTH-independent Cushing syndrome (CS) accounts for 15–20% of endogenous CS. Approximately 10% of these patients have bilateral adrenal lesions where the differential diagnoses are primary bilateral adrenal macronodular hyperplasia (PBMAH), primary pigmented nodular adrenal disease (PPNAD), bilateral cortisol producing adenomas or a unilateral cortisol producing adenoma with a contralateral nonfunctioning adenoma. Also, the prevalence of subclinical CS is high in patients with bilateral incidentalomas. Management of these patients is challenging since the distinction between functioning and non-functioning adrenal masses cannot be determined by imaging. Adrenal venous sampling is the “gold standard” for distinguishing unilateral from bilateral aldosterone production. The role of the adrenal venous sampling (AVS) in patients with ACTH independent CS and bilateral adrenal lesions or normal adrenal glands is still not determined.

Methods: This was a retrospective analysis of 11 consecutive patients evaluated for ACTH-independent CS who were subjected to AVS at our institution between 2009 and 2017.

Results: Eight patients were referred for evaluation of bilateral adrenal incidentalomas, five of whom had subclinical CS and three overt CS. Three additional patients were referred due to overt CS. Thus, in total six patients had overt CS. Overt Cushing’s syndrome: three patients had bilateral adrenal lesions. One of them had a unilateral dominant cortisol production and underwent left adrenalectomy. Two patients had bilateral cortisol production. One of them underwent bilateral adrenalectomy and histopathological diagnosis showed PBMAH. The other patient had a mild CS and was treated medically. Two patients had normal adrenal glands and bilateral cortisol production on AVS. Both underwent bilateral adrenalectomy and the histopathological examination showed PPNAD. The last patient, after extensive investigation, did not have ACTH-independent CS, but cyclic Cushing’s disease. Subclinical CS: all patients had bilateral adrenal lesions. One patient had unilateral dominant cortisol production underwent unilateral adrenalectomy and developed adrenal insufficiency. The histopathological diagnosis was benign adrenal adenoma.

Conclusion: AVS distinctly contributed to appropriate choice of treatment in two of 11 patients. The role of AVS is limited in patients with CS, but may in some cases assist in the management decision of patients with ACTH independent CS and bilateral adrenal lesions or normal adrenal glands.