隆起型胃癌と鑑別を要する非腫瘍性病変

Study of Non-neoplastic Lesions Resembling Protruded Type Gastric Cancers

要旨　内視鏡による胃癌拾い上げ検査は満足のいくものとはなっていない．1997年から2000年までに当施設で行った“拾い上げ目的”の胃内視鏡検査のうち13,717件に生検が付加され，そのうち内視鏡医が下した診断と生検診断が不一致であったものが427例認められた．胃癌拾い上げにおける内視鏡医の観察診断精度は，偽陰性率36.4％，陽性適中度48.6％，有効度96.8％と算出された．偽陽性例270例の内訳は陥凹型病変128例，微細病変105例，隆起型病変36例，びまん型病変1例であった．隆起型胃癌と鑑別を要する非腫瘍性病変として重要なものは，過形成性ポリープ，gastritis cystica polyposa，異所性胃粘膜，inflammatory fibroid polyp，疣状胃炎，食道胃接合部のpseudosarcomatous granulation，胃底腺ポリープなどが挙げられた．これらの病変の特徴を理解して，検査に臨む必要がある．

　Gastric endoscopy is considered to be the standard method for detecting gastric cancer, but we are not satisfied with its detection accuracy. A total of 13,717 gastroscopic examinations with gastric biopsy were carried out at our institution between 1997 and 2000. In 427 examinations endoscopic diagnoses differed from histological diagnoses of biopsy specimens. Regarding endoscopic diagnosis, the false negative rate, positive predictive value and efficiency were 36.4%, 48.6% and 96.8%, respectively. Among 270 false positive cases, depressed lesions, minimal lesions, protruded lesions and diffuse lesions were 128, 105, 36 and 1, respectively. We consider hyperplastic polyps, gastritis cystica polyposa, submucosal heterotopia of gastric glands, inflammatory fibroid polyps, verrucous gastritis, pseudosarcomatous granulation of the esophagogastric junction and fundic gland polyps to be important non-neoplastic lesions resembling protruded-type gastric cancers. Endoscopists should understand the macroscopic features of these lesions in order to distinguish them from protruded-type gastric cancers.