An 18-year-old woman develops weakness, weight gain, amenorrhea, abdominal striae, and behavioral abnormalities. Physical examination reveals lateral visual field loss. Which of the following is the most likely diagnosis?: (A) a functional pituitary tumor, (B) adrenal hyperplasia, (C) anorexia nervosa with bulimia, (D) glioblastoma multiforme
Answer is A. The patient has Cushing's syndrome secondary to an adrenocorticotropic hormone (ACTH)-secreting pituitary tumor. Relatively few of such patients have a large pituitary tumor that affects the visual pathways. Over 50% have a microadenoma, which is under 5 mm in diameter.