A 55-year-old woman comes to the office due to
difficulty swallowing for the past 2 months. The patient describes intermittent difficulty swallowing solids which improves with water or by
chewing her food more. She also reports feeling more tired during this time period. Medical history is noncontributory. Temperature is 36.5°C (97.7°F),
pulse is 110/min, and
blood pressure is 135/85 mmHg. Physical examination reveals pale conjunctiva. Which of the following may be seen on further evaluation of this patient?