High cortisol level in evening , high acth level131pg...mild hypertension.., no mass in suprarenal gland , cuahing appearance..cause?

Possible pituitary: Having a high cortisol with a high acth level is indicative of acth dependent cushings disease. This is a rare disorder due to a pituitary adenoma making too much acth. You may or may not be able to see an abnormality on ct scan or MRI of the pituitary. You should do Dexamethasone suppression testing to confirm the diagnosis. Sometimes the acth is coming from a source outside of the pituitary.