A 42-year-old company executive presents with sudden upper GI bleed (5 litres) of bright red blood, with no significant previous history. The diagnosis is-

Both esophageal varices and duodenal ulcer are causes of massive upper GI bleed. Although it is difficult to reach a diagnosis by clinical history and physical examination alone, variceal bleed is less likely as there are no stigmata of chronic liver disease or portal hypertension.