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Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
Peptic ulceration occurs at all the following sites except -
assistant
The correct answer is  Peptic ulcer

Ulcers are defined histologically as a breach in the mucosa of the alimentary tract that extends through the muscular mucosa into the submucosa or deep.
Peptic ulcers are chronic, most often solitary lesions that occur in any portion of the gastrointestinal tract exposed to the aggressive action of acid/peptic juice.

Peptic ulcers located in the following sites, in order of decreasing frequency :

Duodenum, 1st portion
Stomach, usually antrum
At the gastro - esophageal junction in the setting of gastroesophageal reflux or Barrett's esophagus.
Within the margins of a gastrojejunostomy.
In the duodenum, stomach or jejunum of patients with Zollinger -Ellison Syndrome.
Within or adjacent to Meckel's diverticulum that contains ectopic gastric mucosa.