[Barrett's esophagus: characteristics and evaluation of risk of malignancy]

Barrett's esophagus (B.E.) is defined the replacement of the distal malpighian epithelium of the esophagus by a columnar type epithelium which is considered a precancerous condition. Its aetiology is supposed to derive from the damage induced by esophagitis. We recognize three endoscopic aspects of columnar replacement: flames or tongues of columnar epithelium in continuity to the gastric mucosa (I type), irregular cuff with malpighian islets (II type), complete circumferential cuff with displaced Z line (III type). The evolution of this epithelium into cancer is still debated (prevalence from 0 to 46%), but seems to be particularly elevated in presence of incomplete intestinal metaplasia (I.M.) in which the development of dysplasia is more frequent. The endoscopic examination is essential in the diagnosis and follow-up of B.E. Endoscopy permits other methodological approaches such as histological, chemical, ultrastructural examination aiming to obtain good results in the study of prevalence and incidence of esophagitis, B.E. and adenocarcinoma. It is also possible to perform functional examination. Many Authors joined international protocols to study B.E. in order to obtain uniform data about this condition. A second point of interest is represented by the evaluation of the efficacy of medical treatment to reduce the extension of Barrett's metaplasia and to control the esophagitis. Finally it is possible to detect fluorescence in the dysplastic tissues by laser irradiation using hematoporphyrin derivative and to evaluate their non surgical treatment with photodynamic therapy.