H. pylori未感染胃上皮性腫瘍の内視鏡的特徴—印環細胞癌

Clinical and Pathological Characteristics of Helicobacter pylori-uninfected Signet-ring Cell Cancer of the Stomach ; an Analysis of Case Series

要旨●近年報告が増加しているH. pylori未感染胃癌のうち，特徴的な病態の一つである印環細胞癌について自験例を検証した．2007年4月〜2019年12月の期間に経験した症例は28例で，26例が褪色調ないし白色調平坦型の粘膜癌であった．好発部位は胃角部〜前庭部に集中し，胃底腺と幽門腺の境界領域に相当した．典型例の病理組織像は，粘膜腺頸部に粘液豊富な印環細胞癌が間質を伴わず密に存在しており，粘膜固有層内で腫瘍量が増した症例はみられるが浸潤癌はまれであった．類似の形態と病理組織像を呈した除菌後発見胃癌症例も存在し，本疾患がH. pylori感染により浸潤癌に進展するポテンシャルを有するのか，H. pylori感染に依存しない増殖活性の低い独立した病態であるのか，今後の検討課題と考える．

　We examined all cases at our institute of gastric signet-ring cell carcinoma, which is among the characteristic types of gastric carcinoma without H. pylori infection. Between April 2007 and December 2019, 28 cases were encountered, 26 of which were mucosal carcinomas with characteristic white flat appearance. All cases were observed in the transition zone of the gastric body and the antrum, corresponding to the boundary between the fundic gland and pyloric gland. One typical histopathological finding shows a densely present, mucin-rich signet-ring cell carcinoma in the mucous neck region. In some cases, tumor volume increased in the lamina propria, but invasive carcinoma was rare. We consider future research to discern whether this disease has the potential to progress to invasive carcinoma following H. pylori infection, or if it represents a novel clinical entity as a slow-growing cancer which is independent of H. pylori infection.