Barrett食道の病理組織学的定義

Histologic Examination of Barrett's Esophagus

要旨　Barrett食道は，正常状態では一致している食道胃接合部（EGJ）と扁平上皮円柱上皮接合部（SCJ）とが乖離（SCJが口側に移動）し，これらの間が円柱上皮粘膜で被覆された状態である．SCJの同定は容易であるが，固有筋層もしくは柵状血管で定義されるEGJを病理組織学的に決定するのは困難である．食道であることの指標（食道腺，食道腺導管，扁平上皮島，粘膜筋板の二重化）と参考所見（扁平上皮化生様変化，噴門腺粘膜，胃底腺粘膜の分布）とを総合的に判断し，EGJが存在し得る領域を狭めていき，真のEGJに近づけてゆく必要がある．接合部癌の病理診断ではSCJの肛門側に上述した食道の指標が確認できるか否かが重要であるが，病理組織診断の限界を知り臨床所見を合わせた総合的な診断が望まれる．

　Barrett's esophagus is an abnormal condition in which the squamocolumnar junction（SCJ）is located proximal to the esophagogastric junction（EGJ）, whereas EGJ and SCJ is the same level in normal conditions. The tissue between EGJ and SCJ is lined by columnar epithelium in the Barrett's esophagus. It is easy to identify the SCJ histologically, but it is difficult to histologically determine the line of EGJ defined as the anatomical muscular boundary or the lower end of palisading vessels. Meanwhile we can identify the region of EGJ in reference to histologically reliable markers（esophageal glands and their ducts, esophageal islands, and double muscularis mucosae）indicating the esophageal origin and helpful markers（multilayered epithelium, cardiac glands, and fundic glands）. We should know the limitations of histologic examination and take account of clinical information especially when diagnosing junctional cancers.