胃底腺型胃癌と胃底腺粘膜型胃癌の通常内視鏡・NBI併用拡大内視鏡所見

M-NBI Findings of Gastric Adenocarcinoma of Fundic Gland Type and Adenocarcinoma with Differentiation towards the Fundic Mucosa

要旨●2007年9月〜2015年3月までに内視鏡的・外科的に切除した早期胃癌852病変のうち，病理組織学的に胃底腺型胃癌あるいは胃底腺粘膜型胃癌と診断され，NBI併用拡大内視鏡を施行した病変を抽出した．これらの6病変の通常内視鏡・NBI併用拡大内視鏡所見の特徴を詳細に検討した．胃底腺型胃癌においては，上山ら^4）が既に報告した所見と大差なかったが，胃底腺粘膜型胃癌においては，既報と異なる特徴的なNBI併用拡大内視鏡所見を認めた．胃底腺粘膜型の2例においては，明瞭なDLが同定され，その内側にirregular MV patternかつ/またはirregular MS patternを認めた．すなわち，VS classificationによる癌の診断基準を満たしていた．本研究により，胃底腺粘膜型胃癌は，胃底腺型胃癌と異なる通常内視鏡・NBI併用拡大内視鏡所見を呈することが初めて明らかになった．

　Among the 852 early gastric cancer lesions, which were resected either endoscopically or surgically between September 2007 and March 2015, six lesions were histologically diagnosed as either gastric adenocarcinoma of fundic gland type or adenocarcinoma with differentiation towards fundic mucosa. Conventional and Magnifying endoscopy with narrow-band imaging（M-NBI）was performed, and an investigation was conducted regarding the detailed characteristics of the findings, based on conventional endoscopy and M-NBI. Although no major differences were found compared with the findings already reported by Ueyama et al. for gastric adenocarcinoma of fundic gland type, characteristic M-NBI findings differing from the previously reported findings were seen for adenocarcinoma with differentiation towards the fundic mucosa. In the two cases of adenocarcinoma with differentiation towards the fundic mucosa, a clear demarcation line was observed. Within the demarcation line an irregular MV pattern and or an irregular MS pattern was present. Accordingly, these cases met the diagnostic criteria for cancer based on the vessel plus surface classification system.

　The present study showed for the first time that adenocarcinoma with differentiation towards the fundic mucosa represents different findings on conventional endoscopy and M-NBI from those of the gastric adenocarcinoma of fundic gland type.