表面陥凹型胃癌と鑑別を要する炎症性疾患―内視鏡的鑑別を中心に

Gastric Inflammatory Diseases which Requie Differential Diagnosis from Superficial Depressed Type Early Gastric Cancer-Endoscopic Differential Diagnosis

要旨　表面陥凹型胃癌と鑑別を要する炎症性疾患としてびらん性胃炎，萎縮性胃炎および腸上皮化生を取り上げ，内視鏡所見からの鑑別点を中心に述べた．びらんを鑑別する際には，陥凹部→境界部→辺縁部と内側から外に向かって順序よく見ていくと所見を捉えやすい．そして，悪性びらんの所見が1つでもあれば生検を行うべきである．また，多発性びらんの場合は，形態や大きさが他のびらんと比べて著しく異なっていたり，繊襲上の配列から逸れているびらんは生検をしておくほうが無難である．当施設での診断能を検討したところ，内視鏡的に良性びらんと判断した746病変中9病変（1.2％）がGroup Ⅴであった．一方，内視鏡的にⅡc型早期癌と診断した39病変中3病変（7.7％）は良性病変であった．萎縮の起こっていない胃底腺領域内に，孤立性あるいは限局性に斑状の萎縮粘膜域が存在することがあり，未分化型癌との鑑別が必要である．腸上皮化生性粘膜が広範に拡がってくると，化生していない萎縮性粘膜の部分が浅い陥凹として映り，一見ⅡC型早期胃癌のような様相を示す．これが多発すると1つ1つを鑑別していくのは大変で，大きさや色調などが他の部分と比べて著しく異なっている部位を生検して対処せざるを得ない．

　Endoscopic differential diagnosis of gastric inflammatory diseases, which included erosive gastritis, atrophic gastritis and intestinal metaplasia, and superficial depressed type (Ⅱc type) early gastric cancer was reviewed. In order to make a differential diagnosis of the erosion, it is instructive to observe the erosion from the depressed area to the margin and surrounding area. When even one malignant finding is observed, forceps biopsy is mandatory. In the case of multiple erosions, forceps biopsy is necessary when their size and/or color is clearly different from other erosions, and when their locations deviate from their longitudinal arrangement on the gastric folds. A prospective study was carried out to evaluate the diagnostic accuracy. Of the 746 lesions of which the diagnosis of benign erosion was made endoscopically, 9 lesons (1.2%) yielded the histological diagnosis of Group Ⅴ. On the other hand, of the 39 lesions of which the diagnosis of early gastric cancer was made endoscopically, 3 lesons (7.7%) yielded the histological diagnosis of Group Ⅰ or Ⅱ. In the case of a solitary focal atrophic mucosa located in the fundic gland area, it is necessary to make the differential diagnosis of undifferentiated type cancer. In the cases of widely spreading intestinal metaplasia, the non-metaplastic area may resemble Ⅱc type early cancer, so differential diagnosis is required. The non-metaplastic area of which the size and/or color is clearly different from others should be examined by forceps biopsy.