Improved methods and systems for diagnosing and for treating Cushings syndrome and Cushings Disease are provided herein, including methods and systems for concurrently treating Cushings syndrome and differentially diagnosing Cushings Disease from Ectopic Cushings Syndrome in a patient with an established diagnosis of ACTH-dependent Cushings syndrome. Treatment methods can use glucocorticoid receptor antagonists (GRAs), which differentially affect the ratio of cortisol to ACTH levels in patients having Cushings Disease versus patients having Ectopic Cushings Syndrome. Methods for concurrently treating and differentially diagnosing Cushings Disease from Ectopic Cushings Syndrome include obtaining baseline cortisol and ACTH levels of a patient, treating the patient with a GRA according to a protocol that would typically substantially elevate cortisol levels, obtaining post-treatment cortisol and ACTH levels of the patient, determining a differential relationship between baseline cortisol and ACTH levels and post-treatment cortisol and ACTH levels and providing a positive diagnosis based on the differential relationship.
