Cushing disease, the most common form of ACTH-dependent CS (80–90%), is also known as corticotroph pituitary adenoma or corticotropinoma.[9] Non-pituitary ACTH-secreting tumors (ectopic ACTH secretion) represent 10% to 20% of ACTH-dependent cases. The gene discussed is POMC; the disease is ACTH-producing pituitary gland adenoma.