Question: A 45-year-old lady presented with history of difficulty in swallowing solid foods intermittently for the past one year. There was no history of regurgitation, chest pain, heartburn, vomiting, loss of weight, or atopy. She had no significant past medical history. Her physical examination was unremarkable. The laboratory parameters were within normal limits. The chest radiography and electrocardiograph were normal. The examination of throat did not reveal any abnormality. The barium swallow study (Figure A) revealed a prominent indentation on the posterior aspect of the upper thoracic esophagus.