分化型癌—H. pylori現感染と除菌後の比較

The Endoscopic and Pathological Characteristics of Tubular Adenocarcinoma in Comparison between Helicobacter pylori Infected and Eradicated Patients

要旨●H. pylori現感染と既感染における早期胃癌の範囲診断困難例について検討した．当院の検討では，H. pylori除菌後胃癌は現感染胃癌と比べ，境界が不明瞭である病変が多く，非腫瘍粘膜の被覆や混在を認める割合が高かった．またH. pylori除菌後胃癌の中でもより境界不明瞭となる病変は，0-IIc型が多く，背景粘膜が腸上皮化生であることが少ないという特徴が判明した．境界不明瞭な病変の範囲診断を行う際，white zoneの幅に着目した観察が大切である．また，非腫瘍粘膜の被覆を疑うときは，粘膜構造内に不整な血管がないかを観察することが必要である．さらには，背景粘膜に腸上皮化生を認めない場合，腫瘍を非腫瘍粘膜が被覆する割合が高くなるため，範囲診断には特に慎重な観察が求められる．

　EGC（Early gastric cancer）occurring after successful Helicobacter pylori eradication is difficult to diagnose because of non-neoplastic epithelia covering the periphery of the cancerous surfaces. This might result in an unclear demarcation of the cancer when observed with magnifying endoscopy and narrow-band imaging. EGC that occurs in an area, where the background mucosa contains fundic or pyloric glands, tends to be peripherally covered with non-neoplastic epithelia. Therefore, more careful observation is required when observing EGC located in the areas of fundic or pyloric glands than in the areas of intestinal metaplasia. If an enlarged mucosal structure is found around the tumor margin, it must be suspected that the surface of the cancerous area is covered with non-neoplastic epithelium. Furthermore, it is important to determine whether irregular blood vessels are present in the enlarged mucosal structure.