Abnormal gastrointestinal tract morphology Gastrointestinal ulcer 2022-05-22T14:16:09Z Gastrointestinal ulcers result from the tissue necrosis triggered by mucosal ischemia, ree radical formation and cessation of nutrient delivery, all caused by vascular and microvascular injury such as thrombi, constriction, or other occlusion. A deep defect in the esophageal, gastric, duodenal or intestinal wall involving the entire mucosal thickness and penetrating through the muscularis mucosae.