食道胃接合部腺癌の病理学的特徴

Pathological Characteristics of Adenocarcinoma of the Gastroesophageal Junction

要旨●食道胃接合部癌は，その中心が接合部上下2cm以内に存在する腫瘍と定義された．この腫瘍は単一の病態ではなく，胃噴門部癌とBarrett粘膜，特にSSBEに発生した食道下部腺癌が含まれている．診断するうえで，食道胃接合部を同定すること，発生母地としての食道・胃の同定が重要である．食道であることの診断には，固有食道腺とその導管，扁平上皮島，100μm以上の径を有する組織学的柵状血管，粘膜筋板の二重化が指標となる．内視鏡的切除検体でも複数の標本を作製して観察すれば，ほぼ全例で上記指標が認められる．食道胃接合部癌の定義が明記されてからまだ十分な期間を経ておらず，この腫瘍の病態を明らかにするために，接合部癌の診断，さらにはBarrett食道腺癌または胃噴門癌の鑑別診断を正確に行い，症例を集積することが必要である．

　Adenocarcinoma of the EGJ（esophagogastric junction）is defined as a tumor wherein the center of the tumor is located between 2cm above and 2cm below EGJ. These tumors are not uniform neoplasms but are composed of gastric cardiac adenocarcinoma and adenocarcinoma of Barrett's esophagus, particularly short-segment Barrett's esophagus. The identification of EGJ and gastric or esophageal mucosa as a background mucosa is the most important diagnostic criterion. To diagnose the esophageal origin of the tumor, the following criteria are pathognomonic : the esophageal gland proper and its duct, squamous islands, palisade vessels measuring more than 100μm in the lamina propria, and double muscularis mucosae. These features can be observed in almost all patients with Barrett's adenocarcinoma, even in endoscopically resected specimens. Several years have passed since EGJ cancer was clearly defined. To further clarify the clinicopathologic features of EGJ cancer, we need to collect further specimens of EGJ tumors to assist its correct diagnosis in future.