A 20 year old man without a significant medical history presents to the emergency room with hematemesis. The emergency department stabilizes him hemodynamically and GI is consulted to scope him. He reports no alcohol abuse, no smoking, no NSAID use. In the endoscopy, this lesion is seen:
The gastroenterologist says, "Aha! This is not peptic ulcer disease, esophageal varices, or an arteriovenous malformation."
Challenge: Well, in that case, what is it?
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