質的診断・深達度診断に苦慮した内反性増殖を呈した早期胃癌の1例

A Challenging Case of Early Gastric Cancer with an Inverted Growth Pattern for Qualitative Diagnosis and Depth Assessment

要旨●患者は70歳代，男性．X年に噴門部後壁に粘液が強固に付着し，開口部様の所見を伴う10mm大のわずかに隆起した病変を認めた．生検はGroup 1の診断で，以降，毎年EGDで観察されていた．X＋6年にH. pylori除菌が施行された後，付着粘液の減少が観察された．病変の形態変化は乏しかったが，X＋9年に再生検が施行され，高分化管状腺癌の診断となった．EUSでは第3層に境界明瞭な低エコー腫瘤を認めた．診断的治療目的にESDを施行した．病理組織学的診断は内反性増殖を示した腺癌で，わずかな粘膜筋板の断裂を認め，深達度はSM1であった．開口部様の所見を伴う癌は，内反性増殖性病変の可能性があり，深達度診断の際には注意が必要と考えられた．

　This study reports the case of a male patient in his 70s who had early gastric cancer. In year X, a 10-mm slightly elevated lesion with an orifice-like appearance and strong mucus adhesion was detected on the posterior wall of the gastric cardia. A biopsy of this lesion was performed and it was diagnosed as Group1. The lesion was monitored annually by endoscopy. In year X＋6, Helicobacter pylori eradication was performed, which resulted in a decrease in mucus adhesion. However, the morphology of the lesion did not change much. In year X＋9, another biopsy was performed and a well-differentiated tubular adenocarcinoma was diagnosed. Although endoscopic ultrasonography revealed a hypoechoic tumor in the third layer, endoscopic submucosal dissection was performed for diagnostic and therapeutic purposes. The pathological findings revealed an adenocarcinoma with inverted growth, and the tumor depth was diagnosed as SM1 with a slight rupture of the muscularis mucosae. The presence of an orifice-like appearance in cancer indicates the possibility of an inverted growth pattern, which should be taken into account when assessing the tumor depth by endoscopic ultrasonography.