Table 1.

Various evidences to support the congenital and acquired theories

Evidences	Congenital theory	Acquired theory
Epidemiological	1 Cases in children 2 Cases without demonstrated reflux	1 Association with gastroesophageal reflux 2 Usual occurrence after middle age
Morphological	1 Neonate with columnar-lined esophagus 2 Adult with involvement of entire esophagus 3 Islands of heterotopic/ectopic gastric mucosa 4 Cases with squamous epithelium interposed between Barrett's and gastric mucosa 5 Cases with linear, smooth squamo-columnar junction 6 Presence of parietal and chief cells in Barrett's mucosa	1 Absence of typical cases in fetuses 2 Presence of intestinal-type goblet cells and sulphomucins. 3 Absence of gastrin-containing cells. 4 Endoscopic demonstration of upwards migration of Barrett's mucosa with ongoing gastroesophageal reflux
Experimental	1 Failure of experimental models 2 Absence of reversion to squamous epithelium after antireflux operation	1 Animal models. 2 Regression after successful antireflux surgery. 3 Acquisition of Barrett's mucosa after onset of reflux following esophagogastrostomy, Heller myotomy and esophagojejunostomy.

Modified from Hamilton SR. Pathogenesis of columnar cell-lined (Barrett's) esophagus. In: Spechler S J, Goyal R K, (Eds.) Barrett's esophagus: Pathophysiology, diagnosis, and management. New York: Elsevier Science, 1985: 29-37.