噴門部の微小な衝突癌の1例―低分化型扁平上皮癌smと腺管腺癌m

Collision Carcinoma at the Cardia Diagnosed by Endoscopy, Report of a Case

要旨　患者は52歳の男性で，上部消化管X線検査および内視鏡検査により滑脱型食道裂孔ヘルニアが発見され，そのヘルニア内にⅡc＋Ⅱaおよびその後壁側に小さなⅡcを認め，内視鏡下生検により，それぞれ扁平上皮癌と腺管腺癌と診断された．手術標本の病理組織学的検索では，粘膜下層まで浸潤した低分化型扁平上皮癌（19×15mm）の辺縁帯に接して，粘膜層内にとどまる腺管腺癌（9×6mm）があった．更に精査したところ組織学的に両者が衝突している部位が確認された．衝突部位では粘膜表層の一部に腺管腺癌が存在し，粘膜深層から粘膜下層まで低分化型扁平上皮癌が浸潤し，両者の間に形態的移行像は認められなかった．以上の所見から噴門部における衝突癌と診断した．

　A 52-year-old man was admitted to our hospital complaining of epigastric pain. Upper gastrointestinal series and endoscopic examination showed a Ⅱc ＋ Ⅱa lesion bordering on a small Ⅱc lesion at the cardia of the stomach with sliding hernia (Fig. 1 and 3). Biopsy specimens obtained from the Ⅱc ＋ Ⅱa and small Ⅱc lesions demonstrated squamous cell carcinoma and adenocarcinoma respectively (Fig. 4).

　Proximal gastrectomy with partial esophagectomy was performed and examination of the resected specimen showed a Ⅱc ＋ Ⅱa lesion measuring 19×15 mm and a Ⅱc lesion measuring 9×6 mm located close to each other (Fig. 6). Histologically, the Ⅱc ＋ Ⅱa lesion consisted of squamous cell carcinoma infiltrating into the submucosa, whereas the small Ⅱc lesion was composed of adenocarcinoma localized in the mucosa. The serial sections revealed the area where these two carcinomas collide with each other, and there was no histological transition between them (Fig. 7).

　Thus, these histological findings of the two cancerous lesions fit well with the concept of collision carcinoma.