Preferential repair by squamous epithelium of thermal induced injury to the proximal stomach in patients undergoing ablation of Barrett's esophagus

Background: The presence of extensions of squamous epithelium into the prox imal stomach in patients undergoing routine upper endoscopy has recently be en described. The factors that may favor development of squamous epithelium within the proximal stomach remain unknown. Methods: Patients with Barrett's esophagus who agreed to undergo ablation o f Barrett's epithelium by using multipolar electrocoagulation were included . Patients were treated with a high dose of a proton pump inhibitor. The co lumnar-appearing mucosa was systematically treated. Occasionally, thermal i njury was inadvertently induced in the proximal stomach. On endoscopy perfo rmed 4 to 6 weeks after treatment, the presence of squamous epithelium exte nding into the proximal stomach was documented. The use of Lugol's stain as sisted in confirming the squamous nature of the abnormal tissue, which was confirmed histologically by cytokeratin immunohistochemistry. Results: The 12 patients included in the study had a mean length of Barrett 's epithelium of 3.8 +/- 0.7 cm. Patients were treated with omeprazole, mea n dose 66 +/- :6.0 mg, and had a mean percent total time that the pH was le ss than 4 of 1.9 +/- 0.8. The mean length and width of gastric squamous ext ensions were 1.7 +/- 0.2 cm and 0.8 +/- 0.1 cm, respectively. None of the s quamous extensions into the stomach were documented before mucosal ablation . The extensions stained positively for cytokeratin 13 and negatively for c ytokeratin 8, thereby confirming their squamous nature. Conclusions: Thermal injury to the proximal stomach in patients undergoing ablation of Barrett's epithelium and profound acid suppression results in r epair by squamous epithelium. Recognition of this lesion is essential becau se it may lead to confusion as to the location of the esophagogastric junct ion in subsequent endoscopic evaluations.