Cameron Lesions in Hiatal Hernia

A 71-year-old woman with a 10-year history of GERD and a known large hiatal hernia (>5 cm) presents with transfusion-dependent iron-deficiency anemia (Hb 8.6 g/dL, MCV 71, ferritin 6 ng/mL). Upper endoscopy reveals linear erosions and shallow ulcers on the crests of gastric mucosal folds at the diaphragmatic indentation within the hernia sac, as marked **B** in the diagram. Two prior colonoscopies were unremarkable, and biopsies exclude malignancy and H. pylori infection. Which of the following best describes the pathophysiological mechanism underlying the lesions marked **B**?