(… OH-muh) A rare tumor that makes the hormone adrenocorticotropin (ACTH), which causes the adrenal glands to make too much cortisol. ACTHomas can lead to Cushing syndrome. Signs and symptoms of ACTHomas and Cushing syndrome include a round face, thin arms and legs, severe fatigue and muscle weakness, high blood pressure, high blood sugar, purple or pink stretch marks on the skin, and weight gain, especially in the abdomen. ACTHomas usually form in the pituitary gland or in the islet cells of the pancreas, but they may also form in other organs, including the lung, thyroid, and thymus. ACTHomas may be benign (not cancer) or malignant (cancer). Also called adrenocorticotropic-secreting tumor.