Objective: To review the challenges encountered in the diagnostic work-up and management of patients with subclinical Cushing's syndrome (SCS) and bilateral adrenal masses to aid in the case description of a patient with SCS and adrenocorticotropic hormone (ACTH)-independent macronodular adrenal hyperplasia (AIMAH).
Methods: We describe our experience managing a patient with AIMAH and SCS. This case report is followed by an extensive review of the literature regarding differential diagnoses, work-up including adrenal venous sampling (AVS), and treatment of SCS with bilateral adrenal masses.
Results: A 51-year-old female who was diagnosed with recent onset hypertension and diabetes mellitus type 2 was evaluated for adrenal masses discovered incidentally on computed tomography (CT). She did not have any Cushingoid features. Magnetic resonance imaging (MRI) of abdomen was performed for further evaluation. Hormonal evaluation came back consistent with SCS. The AVS results were consistent with bilateral autonomous cortisol hypersecretion without lateralization. Collectively, the findings favored the diagnosis of bilateral AIMAH. A left adrenalectomy was performed, and the patient's clinical response was favorable with improvement in blood pressure (BP) accompanied by significant weight loss. Follow-up hormonal testing for autonomous cortisol hypersecretion was within the target range.
Conclusions: AIMAH is a rare cause of SCS. AVS is a useful diagnostic tool that helps localize the source of autonomous cortisol hypersecretion in ACTH-independent SCS with bilateral adrenal masses, especially if radiological features are inconclusive. Patients undergoing unilateral adrenalectomy should be followed for monitoring of clinical response, as well as progression of AIMAH in the contralateral adrenal gland.