BARRETT'S OESOPHAGUS= also known as columnar lined oesophagus. Def-whn metaplastic change occur in lining mucosa of oesophagus, thn it is called barrett's oesophagus.. It is premalingnant lesion n ulcer in barrett's clo is barrett's ulcer. B)PATHOGENESIS= repeated reflux results in shifting of oesephagogastric junction upwards wich increases reflux resultimg in intestinal metaplasia of middle n lower oesophagus. C)pathological types= 1- gastric type wid chief n parietal cells. 2-intestinal type..3- junbtional type.. D)clinical types..= 1-long segment..2-short segment.. E)incidence of malignancy= 25 times more prone to CA lower n middle oesophagus.. F)types of dysphasia= 1-low grade..2-high grade.. G)carcinoma in barrett's oesophagus= 1- it wil b invasive..2- it is more proximal.. 3- carries poor prognosis. 4- 25 times increased risk. H) TREATMENT= 1-laser photodynamic therapy..2-argon beam plasma coagulation..3- high dose proton pump inhibitors for 8 wks. 4- oesophagectomy in cases of high grade dysplasia.. I)COMPLICATIONS= 1- oesophageal ulber..2-oesophageal stricture..3-dysplasia ..4-adenocarcinoma..