What is the significance of high cortisol levels?

Adrenal or Pituitary. Excessive production of cortisol may result from a tumor in pituitary producing a hormone that stimulates the adrenal gland. Lesions in the adrenal gland, hyperplasia, adenoma, carcinoma, may also cause increase in cortisol levels. You need to consult your doctor and/or an endocrinologist.