inverted growthを呈した巨大早期胃癌をESDで切除した1例

An Early Gastric Cancer with Inverted Growth that was Treatable by Endoscopic Submucosal Dissection, Report of a Case

要旨　患者は62歳，男性．高度貧血による意識消失で来院した．上部消化管精査で十二指腸球部へ逸脱する巨大な胃隆起性病変が認められた．隆起は丈が高く非常に柔軟で，基部は広範な扁平隆起を呈していた．内視鏡的粘膜下層剥離術（ESD）を施行した結果，高分化管状腺癌，SM1であった．隆起部では癌の内反性増殖（inverted growth）がみられ，粘膜内の腫瘍腺管が機械的刺激で生じた粘膜筋板の断裂部から粘膜下へ侵入，増殖したと推測した．

　A 62-year-old man visited Shizuoka Hospital with an episode of consciousness loss. Regular check up showed anemia, which led to a demonstration of a gastric polypoid lesion extending from the body, through the pylorus, into the duodenum. Further examination on endoscopy showed a wide-spreading mucosal base, without deep invasion, and an erosion on the top. We judged this lesion was resectable with ESD（endoscopic submucosal dissection）, which was successfully carried out. Histologically the lesion was a well differentiated tubular adenocarcinoma with minimal invasion of the submucosal tissue despite a huge and massive mucosal component（inverted growth）. We think this morphology was made by misplacement of the tumor by chronic mechanical stimuli, resulting in thickening and disruption of the muscularis mucosae.