Hypercortisolism, is a condition characterized by high levels of the hormone cortisol in the body. In some cases, hypercortisolism may be caused by a benign tumor on one of the adrenal glands, which are responsible for producing cortisol. These tumors are usually small and non-cancerous, but they can lead to excessive cortisol production and a range of symptoms, including weight gain, muscle weakness, and high blood pressure.