A 64-year-old man with diabetes and chronic kidney disease presents with hematemesis/coffee-ground emesis and hypotension/shock (after urosepsis or severe dehydration). Labs show anemia, leukocytosis, and acute kidney injury.
Urgent upper endoscopy shows diffuse circumferential black discoloration of the distal two-thirds of the esophagus with a sharp cutoff at the gastroesophageal (GE) junction.
What is the diagnosis?