[Subclinical Cushing's syndrome in adrenal incidentalomas]

In the heyday of high-tech medicine, the incidental discovery of an adrenal mass is a frequent event owing to the routine use of sophisticated radiological techniques. The potential harm to health associated with incidentally discovered cortical adenoma, the most frequent tumor among adrenal incidentalomas, is unclear at present. Incidentally discovered adrenal adenoma may secrete cortisol autonomously, in a way that is no longer under close control by pituitary feedback, in 5 to 20% of cases. At present, data are insufficient to estimate the outcome of patients with subclinical Cushing's syndrome. However, evidence is gathering that subclinical Cushing's syndrome may contribute to develop the phenotype of insulin resistance thus portending to atherosclerosis and relevant cardiovascular complications. It is tempting to speculate that subclinical Cushing's syndrome represents a very mild variant of endogenous glucocorticoid excess syndrome. Even if progression to overt glucocorticoid excess is rare, subclinical Cushing's syndrome has the potential to carry an adverse prognosis. At present, data are insufficient to indicate the superiority of a surgical or nonsurgical approach to manage patients with subclinical hyperfunctioning adrenal cortical adenoma. It is of the utmost importance to establish collaborative prospective studies with clearly defined entry criteria and standardized evaluation protocols and treatment modalities to appraise the natural history and long-term morbidity of clinically inapparent adrenal adenoma and subclinical Cushing's syndrome.