食道胃接合部癌とBarrett食道癌の鑑別は必要か─臨床の立場から

Is Differential Diagnosis of Barrett's Esophageal Adenocarcinoma and Gastric Cardia Cancer Necessary?

要旨●SSBE由来Barrett食道癌の多くは食道胃接合部癌に該当し，噴門部胃癌との鑑別が問題となる．病理組織学的に大きな違いはないとする報告もある一方で，発癌の経路が異なる可能性も示唆されている．Barrett食道癌症例は若く，右側に多くみられる．また，食道裂孔ヘルニアや逆流性食道炎が多く，H. pylori感染や胃粘膜萎縮は少ないという点で，Barrett食道癌以外の食道胃接合部腺癌と明らかに背景が異なっていた．術前にBarrett食道癌を鑑別することはある程度可能であり，やはり食道胃接合部の注意深い内視鏡観察を行い，Barrett粘膜の有無および食道胃接合部腺癌の由来を評価することは重要と思われる．

　In most cases, Barrett's esophageal adenocarcinoma derived from SSBE（short-segment Barrett's esophagus）corresponds to carcinoma of the EGJ（esophagogastric junction）. With carcinoma of EGJ, it is sometimes difficult to distinguish superficial Barrett's esophageal adenocarcinoma from gastric cardia cancer. Some studies have reported that there is little pathological difference between Barrett's esophageal adenocarcinoma and gastric cardia cancer. On the other hand, some articles have suggested a possible difference in the mechanism of carcinogenesis between Barrett's esophageal adenocarcinoma and gastric cardia cancer. In the present study, patients with Barrett's esophageal adenocarcinoma were younger and their lesions tended to be located on the right side of EGJ compared with those with gastric cardia cancer. In addition, the incidence of esophageal hiatal hernia and gastroesophageal reflux disease in these patients was greater, and there was less H. pylori infection and atrophy of the gastric mucosa. These characteristics of patients with Barrett's esophageal adenocarcinoma obviously differed from those with gastric cardia cancer. Endoscopic diagnosis of Barrett's esophageal adenocarcinoma is possible to a certain extent. It is thus important to carefully observe EGJ for evidence of carcinoma and evaluate the existence of Barrett's esophagus in the surrounding mucosa.