Case Study Patient: Mr. Khan, a 52-year-old businessman from Lahore, Pakistan. Presenting Complaint: Mr. Khan presented with a three-month history of severe heartburn, frequent vomiting, and persistent epigastric pain. He also reported unintentional weight loss and worsening fatigue. Medical History: No significant medical history, except occasional indigestion treated with over-the-counter medications. Examination: Upper endoscopy revealed...