Clinical and Metabolic Outcomes of Adrenalectomy Versus Conservative Management in Mild Autonomous Cortisol Secretion.

Adrenalectomy and conservative management are therapeutic approaches for mild autonomous cortisol secretion; however, their comparative clinical impact in routine practice remains uncertain. We aimed to evaluate real-world hormonal, clinical, and metabolic outcomes according to the treatment strategy in patients with mild autonomous cortisol secretion. This single-center retrospective observational study included consecutive patients with adrenal incidentaloma fulfilling guideline-based diagnostic criteria for mild autonomous cortisol secretion between January 2015 and December 2024. Sixty-five patients with complete hormonal evaluation and follow-up data were analyzed and classified into surgery (n=23) and conservative (n=42) groups. Demographic characteristics, adenoma features, comorbidities, hormonal parameters, and metabolic outcomes were assessed at baseline and at the final follow-up. The median follow-up duration was approximately 3 years and similar between groups (p>0.05). At baseline, the body mass index, adenoma size, and cortisol levels after the 1-mg dexamethasone suppression test were significantly higher, while adrenocorticotropic hormone levels were lower in the surgery group (p=0.02, p=0.02, p=0.036, and p<0.01, respectively). During the follow-up, adrenocorticotropic hormone levels increased and post-dexamethasone suppression test cortisol levels significantly decreased after adrenalectomy (p=0.001 and p=0.036, respectively), whereas metabolic parameters and comorbidity profiles remained largely unchanged. In the conservative group, total cholesterol increased modestly over time (p=0.048), with no significant changes in other clinical outcomes. No significant difference in comorbidity progression was observed between treatment strategies. In this real-world cohort, adrenalectomy resulted in clear hormonal improvement without parallel short-term metabolic or clinical benefits compared with conservative management. These findings highlight the heterogeneous clinical expression of mild autonomous cortisol secretion and underscore the importance of individualized patient selection for surgery.