For ectopic adrenocorticotropic hormone (ACTH) syndrome (EAS), when surgery is not feasible, or in cases of severe biochemical disturbances, immunosuppression or mental instability, medical therapy with agents such as etomidate is indicated. We present our experience in using etomidate for a 41-year old female with EAS secondary to a malignant mediastinal paraganglioma. We were able to demonstrate that etomidate can be used effectively to control severe hypercortisolism in a lower dose than previously described.