An unusual cause of dysphagia

David, a 53-year-old male office clerk of Chinese descent, presents with a three-month history of progressive swallowing difficulty.
David reports having experienced difficulty with solid foods initially, consequently changing his diet to ‘soft foods’.
His symptoms have worsened over the past two weeks; he feels liquids get ‘held up’ in his chest, resulting in projectile vomiting.
There is no associated haematemesis or coffee-ground vomitus.