[Diagnostics and surgery of mild autonomous cortisol secretion (MACS)]

Mild autonomous cortisol secretion (MACS) is diagnosed in up to 50% of benign hormonally active adrenal tumors. Due to a growing number of detected adrenal incidentalomas a thorough diagnostic work-up is needed to critically decide on conservative or surgical treatment. In incidentalomas > 1 cm the 1 mg dexamethasone suppression test is recommended along with a native computed tomography scan. Patients without overt Cushing's symptoms but pathological results in dexamethasone suppression test (cortisol > 1.8 µg/dl) are labelled MACS. In these patients both mortality and prevalence of diabetes mellitus, arterial hypertension and dyslipidemia are elevated. In unilateral adenomas and the presence of comorbidities adrenalectomy should be discussed in an interdisciplinary panel. Postoperatively, an endocrinological follow-up is required to control the hypopituitary-adrenal axis. With a conservative approach endocrinological control is only recommended with deterioration of comorbidities. After adrenalectomy, improvement of arterial hypertension and bone mineral density have been shown in meta-analyses.