Detecting Mild Autonomous Cortisol Secretion in Patients With Adrenal Incidentaloma

Mild Autonomous cortisol secretion (MACS) is defined as the hypersecretion of cortisol by the adrenal glands, independent of Adrenocorticotropic Hormone (ACTH) regulation. MACS can be a challenging diagnosis for clinicians to make. It is commonly associated with adrenal incidentalomas (AI), the incidental finding of adrenal gland masses on cross-sectional imaging. There are a variety of adverse clinical conditions associated with MACS, including central obesity, hypertension, impaired fasting glucose due to insulin resistance, and dyslipidemia, which together comprise the "metabolic syndrome," as well as type 2 diabetes mellitus, cardiovascular disease, osteoporosis with vertebral fractures, and early mortality. Androulakis et al. concluded that patients with AI, even without hypertension, diabetes, and/or dyslipidemia, may still have adverse cardiovascular outcomes, possibly due to increased insulin resistance and endothelial dysfunction linked to subtle cortisol excess. There is also a reported association of non-alcoholic fatty liver disease (NAFLD), an increasingly significant cause of morbidity and mortality, with the metabolic syndrome and diabetes, as well as hypercortisolism. However, the link between MACS and NAFLD has not been well delineated, nor has the effect of treatment with MACS on NAFLD been explored.

Given the findings cited above, there may be benefit in treating patients with AI and MACS with medical therapy. Therefore, identifying those individuals who have the metabolic syndrome or its components, bone disease, NAFLD, or increased cardiovascular risk related to excess cortisol secretion is essential but difficult.