These tumors give off their own cortisol which impacts many functions of the body including hormone production. In my daughter's case she had symptoms of missed periods and then no ovulation at all due to imbalance of estrogen and testotrone, weight gain to face and abdomen - basic Cushing's syndrome but there are other symptoms as well such as fatigue, muscle weakness and unwanted facial hair. I haven't learned about the fatal effects except in what I have read which is prognosises that are in the single digits- I believe mostly because it isn't caught until its too late to operate or worse.