非乳頭部十二指腸SM浸潤癌の臨床病理学的特徴—内視鏡切除例を中心に

Clinicopathologic Features of Nonpapillary Duodenal Submucosal Invasive Carcinoma：A Focus on Endoscopically Resected Cases

要旨●非乳頭部十二指腸上皮性腫瘍の粘膜下浸潤（SM）癌はまれであるが，SM癌ではリンパ節転移のリスクが高く，正確な深達度診断を行っていくことが求められている．文献や当院の症例では，SM癌は局在として主乳頭部より口側に多く，腫瘍径はM癌と差はなかった．肉眼型ではM癌と比較してSM癌は混合型（Type 0-IIa＋IIc型）やSMT様隆起を伴うことが多かった．NBI拡大内視鏡観察では，白色不透明物質（WOS）の消失を認めた．病理組織学的には，SM癌では脈管侵襲の割合が多かった．また，粘液形質ではSM癌では胃型形質が多いと報告されている．胃型形質の腫瘍は悪性度が高いと報告されており，主乳頭より口側，WOSの消失など胃型の形質を疑う所見を認めた場合にはSM癌の可能性を考慮する必要がある．

　Although submucosal（SM）carcinoma of the nonpapillary duodenal epithelial tumor is rare, it carries a high risk of lymph node metastasis and requires a precise depth diagnosis. Both in previously reported cases and our case, SM carcinoma was more localized on the oral side of the papilla and did not differ from M carcinoma in terms of tumor diameter. Compared with M carcinoma, SM carcinoma was more often mixed（Type 0-IIa＋IIc）or accompanied by SMT-like elevations in its gross appearance. Magnified endoscopy revealed the disappearance of a white opaque substance（WOS）. Pathologically, SM carcinomas had a high vascular invasion rate. Additionally, the gastric phenotype was more commonly observed in SM carcinomas. Tumors with a gastric phenotype are more likely to be malignant ; therefore, the possibility of SM carcinoma should be considered in cases with findings suggestive of a gastric phenotype, such as localization on the oral side of the papilla and disappearance of WOS.