Subclinical Cushing's syndrome

The routine use of abdominal procedure has significantly increased the incidental finding of adrenal masses. The prevalence of these tumors, commonly defined as adrenal incidentalomas, ranges between 2-3% in autopsy and 4% in radiological series, reaching 5-8% in oncological studies and increasing with patients age. Although clinically silent, in 5-20% of cases, adrenal incidentalomas are responsible for a subtle cortisol overproduction, commonly defined as "subclinical Cushing's syndrome" (SCS). This term is used to describe autonomous cortisol secretion in patients who don't have the typical signs and symptoms of hypercortisolism. The optimal strategy for identification and management of SCS is unknown; the standard biochemical tests used to screen for overt Cushing's syndrome are generally ill-suited to the assessment of patients who have no, or only very mild signs of cortisol excess, then many tests aimed to study the hypothalamus-pituitary-adrenal axis (HPA) axis do not have sufficient sensitivity to recognize very mild degree of cortisol excess. An increased frequency of hypertension, central obesity, impaired glucose tolerance or diabetes, hyperlipemia and osteoporosis has been described in patients with SCS since patients are exposed to a chronic albeit slight, cortisol excess; however, there is not evidence-based demonstration of long term complications and, consequently, the management of this condition is largely empirical. Adrenalectomy or medical management of associated disease has been indicated as therapeutic options due to lack of data demonstrating the superiority of a surgical or non-surgical treatment.